山田 幸生

名誉教授・その他関係者名誉教授
脳・医工学研究センター客員教授
  • プロフィール:
    1.高温熱交換器の研究
    2.散乱吸収媒体内の放射エネルギー輸送の研究
    3.生体内熱輸送の研究
    4.生体内光伝播の研究
    5.近赤外光による生体の光断層イメージングの研究
    6.近赤外分光による無侵襲血糖値測定の研究
    7.近赤外分光による水を含む流体の温度測定に関する研究
    8.近赤外蛍光による生体内情報の計測

学位

  • 工学士, 東京工業大学
  • Bachelor of Engineering, Tokyo Insititute of Technology
  • 工学修士, 東京工業大学
  • Master of Engineering, Tokyo Institute of Technology
  • 工学博士, 東京工業大学
  • Doctor of Engineering, Tokyo Institute of Technology

研究キーワード

  • Radiation heat transfer
  • Near infrared spectroscopy
  • Noninvasive measurement of blood glucose level
  • Diffuse optical tomography
  • Optical tissue diagnosis
  • Biomedical engineering
  • 放射伝熱
  • 近赤外分光
  • 無侵襲血糖値測定
  • 光断層イメージング
  • 生体光診断
  • 生体医用工学

研究分野

  • ものづくり技術(機械・電気電子・化学工学), 熱工学
  • ライフサイエンス, 生体材料学
  • ライフサイエンス, 生体医工学

経歴

  • 2013年04月01日 - 2020年03月31日
    国立研究開発法人 産業技術総合研究所, 健康工学研究部門, 客員研究員
  • 2019年09月01日
    東京大学, 大学院新領域創成科学研究科 人間環境学専攻, 特任研究員
  • 2019年04月01日
    電気通信大学, 脳・医工学研究センター, 客員教授
  • 2013年06月01日 - 2019年03月31日
    日本大学, 工学部, 客員教員
  • 2013年04月01日 - 2019年03月31日
    電気通信大学, 脳科学ライフサポート研究センター, 特任教授
  • 2013年04月01日 - 2014年03月31日
    電気通信大学, 大学院情報理工学研究科、情報理工学部, 特命教授
  • 2013年04月01日
    電気通信大学, 名誉教授
  • 2013年04月01日
    脳科学ライフサポート研究センター, 特任教授
  • 2001年04月01日 - 2013年03月31日
    電気通信大学, 電気通信学部知能機械工学科, 教授
  • 1998年05月01日 - 2001年03月31日
    工業技術院機械技術研究所, 基礎技術部, 基礎技術部長
  • 1993年04月01日 - 1998年04月30日
    工業技術院機械技術研究所, 基礎技術部バイオメカニクス研究室, バイオメカニクス研究室長
  • 1991年04月01日 - 1993年03月31日
    工業技術院機械技術研究所, エネルギー部熱工学課, 熱工学課長
  • 1974年04月01日 - 1991年03月31日
    工業技術院機械技術研究所, エネルギー部熱工学課, 研究員および主任研究官

学歴

  • 1973年03月
    東京工業大学, 理工学研究科, 機械工学専攻
  • 1970年03月
    東京工業大学, 理工学部, 機械工学科
  • 1963年04月 - 1966年03月
    山形県立米沢興譲館高等学校, 普通科, 日本国

委員歴

  • 2011年08月 - 2012年07月
    大会長, 日本光脳機能イメージング研究会, 学協会
  • 2009年05月 - 2010年05月
    副会長, 日本伝熱学会, 学協会
  • 2006年01月 - 2009年12月
    Editorial Board Member for Physics in Medicine and Biology, Institute of Physics, 学協会
  • 2006年01月 - 2009年12月
    学術雑誌「医学および生物学の物理」の編集委員, 英国物理学会, 学協会
  • 2006年05月 - 2008年05月
    監事, 日本伝熱学会, 学協会
  • 2006年01月 - 2008年03月
    Journal of Thermal Science and Technology編集委員会, 日本機械学会, 学協会
  • 2005年10月 - 2008年02月
    110周年記念事業委員会式典小委員会, 日本機械学会, 学協会
  • 2005年04月 - 2007年03月
    バイオエンジニアリング部門総務委員長, 日本機械学会, 学協会
  • 2005年04月
    Fellow, Japan Society of Mechanical Engineers, 学協会
  • 2005年04月
    フェロー, 日本機械学会, 学協会
  • 2004年11月
    fellow, Institute of Physics, 学協会
  • 2004年11月
    フェロー, 英国物理学会, 学協会
  • 2002年04月 - 2004年03月
    熱工学部門運営委員, 日本機械学会, 学協会
  • 2002年04月 - 2004年03月
    表彰部会, 日本機械学会, 学協会
  • 2001年04月 - 2003年03月
    国際交流委員会, 日本機械学会, 学協会
  • 2002年04月
    世話人, 日本光脳機能イメージング研究会, 学協会
  • 1996年 - 2002年
    Program Committee Member, Biomedical Topical Meeting, Optical Society of America, 学協会
  • 1996年 - 2002年
    生体医用光学トピカルミーティング・プログラム委員, 米国光学会, 学協会
  • 1997年05月 - 1999年05月
    「生体内輸送・伝播に関する研究会」幹事, 日本伝熱学会, 学協会
  • 1996年05月 - 1998年05月
    理事, 日本伝熱学会, 学協会

受賞

  • 受賞日 2015年01月
    日本機械学会 バイオエンジニアリング部門
    功績賞(第19回 2014年度), 山田幸生
    その他の賞, 日本国
  • 受賞日 2015年01月
    日本機械学会 バイオエンジニアリング部門
    日本機械学会 バイオエンジニアリング部門 功績賞(第19回 2014年度), 山田幸生
    その他の賞, 日本国
  • 受賞日 2014年05月
    日本伝熱学会
    名誉会員, 山田幸生
    その他の賞, 日本国
  • 受賞日 2014年05月
    日本伝熱学会
    日本伝熱学会 名誉会員, 山田幸生
    その他の賞, 日本国
  • 受賞日 2011年11月
    (社)日本伝熱学会
    日本伝熱学会創立50周年記念功労者表彰
  • 受賞日 2011年06月
    日本伝熱学会
    近赤外分光法を応用した微量水溶液の温度イメージング
    日本伝熱学会学術賞, 角田直人;近藤克哉;尾崎敦之;有本英伸;山田幸生
    学会誌・学術雑誌による顕彰
  • 受賞日 2005年04月
    日本機械学会賞(論文)"Anatomical and Functional Images for in vitro and in vivo Tissues by NIR Time-domain Diffuse Optical Tomography"
  • 受賞日 2005年04月
    日本機械学会賞(論文), 趙 会娟;高 峰;谷川ゆかり;本間一弘;小野寺陽一;山田幸生
    学会誌・学術雑誌による顕彰
  • 受賞日 2005年01月
    日本機械学会バイオエンジニアリング部門 第13回業績賞「光を用いた生体計測に関する基礎研究ほかの優れた業績」
  • 受賞日 2005年01月
    光を用いた生体計測に関する基礎研究ほかの優れた業績
    日本機械学会バイオエンジニアリング部門 第13回業績賞
    その他の賞
  • 受賞日 2002年12月
    Singapore
    Outstanding Paper Award: "LIGHT PROPAGATION IN BIOLOGICAL TISSUES AND OPTICAL DIAGNOSTICS BY IMAGING AND SPECTROSCOPY," ICBME 2002 (International Congress on Biological and Medical Engineering 2002)
    シンガポール共和国
  • 受賞日 2002年12月
    Singapore
    Outstanding Paper Award, ICBME 2002 (International Congress on Biological and Medical Engineering 2002)
    国際学会・会議・シンポジウム等の賞
  • 受賞日 2000年04月
    科学技術庁
    生体の光学ファントム作製法
    注目発明選定, 山田幸生;谷川ゆかり
    その他の賞
  • 受賞日 1996年04月
    科学技術庁長官賞,研究功績者表彰:「光断層イメージングシステム」
  • 受賞日 1996年04月
    科学技術庁
    光断層イメージングシステム
    科学技術庁長官賞,研究功績者表彰
    その他の賞
  • 受賞日 1994年08月
    工業技術院機械技術研究所
    生体熱工学と光断層イメージングシステムに関する研究
    機械技術研究所長賞 研究業績賞, 山田幸生
    その他の賞
  • 受賞日 1993年04月
    科学技術庁長官
    光CT装置
    注目発明選定, 山田幸生
    その他の賞

論文

  • Determination of the absorption and reduced scattering coefficients by CW spatially resolved spectroscopy with long source-detector distances at high and low internal reflections
    Yukio Yamada; Hiroshi Kawaguchi; Toru Yamada
    Progress in Biomedical Optics and Imaging - Proceedings of SPIE, 12376巻, 出版日 2023年, Many studies on CW spatially resolved spectroscopy (CW-SRS) have been conducted to noninvasively determine the optical properties, particularly the absorption and reduced scattering coefficients, μa and μs′, of biological tissues. To determine both μa and μs′, conventional CW-SRS employs measurements of the diffuse reflectances at short source-detector (SD) distances in the non-diffusion regime. In contrast, CW-SRS with long SD distances in the diffusion regime can determine only the effective attenuation coefficients, μeff = (3μaμs′)1/2 without separating μa and μs′. This study proposes a new method to separately determine μa and μs′ using CW-SRS with long SD distances, extending to conditions with high and low internal reflection at the boundary of homogeneous semi-infinite media. The proposed method used two ratios of the diffuse reflectances at two long SD distances, and μa and μs′ were determined by fitting the theoretical ratios to the measured values. Numerical simulations were conducted to validate the proposed method. As a light propagation model, the analytical solution of the time-dependent photon diffusion equation under the partial-current boundary condition (TD-DE-PCBC), which is verified for high internal reflection, was employed. Simulated measurements of the two ratios were compared with the calculated ratios (so-called look-up tables) using the TD-DE-PCBC to determine both μa and μs of the media. Simulation results demonstrate the validity of the proposed method. The effects of deviations in the SD distances and internal reflection coefficients were evaluated. Changes in the light propagation paths in the medium are discussed, and methods to realize the proposed method are suggested.
    研究論文(国際会議プロシーディングス)
  • A comparative study of the delta-Eddington and Galerkin quadrature methods for highly forward scattering of photons in random media
    H. Fujii; G. Chiba; Y. Yamada; Y. Hoshi; K. Kobayashi; M. Watanabe
    Journal of Computational Physics, Elsevier, Vol. 423巻, Paper No. 109825号, 掲載ページ 1-14, 出版日 2020年09月, 査読付
    研究論文(学術雑誌), 英語
  • Erratum: Near-infrared measurement of water temperature near a 1-mm-diameter magnetic sphere and its heat generation rate under induction heating (Journal of Applied Physics (2017) 122 (044901) DOI: 10.1063/1.4995284)
    Naoto Kakuta; Keisuke Nishijima; Katsuya Kondo; Yukio Yamada
    Journal of Applied Physics, American Institute of Physics Inc., 126巻, 23号, 出版日 2019年12月21日, In Sec. II A of the above published paper,1 we showed α = 4.1 × 10−3K−1mm−1 and αf = 4.0 × 10−3K−1mm−1. However, these values were incorrect. We mistakenly put the values used for the wavelength of 1412 nm. The correct values for 1150 nm in this paper are 2.9 × 10−4K−1mm−1 and 2.8 × 10−4K−1mm−1, respectively. These corrections do not affect the results because the correct values were used in the calculation.
    研究論文(学術雑誌), 英語
  • Numerical treatment of highly forward scattering on radiative transfer using the delta-M approximation and Galerkin quadrature method
    藤井 宏之; 千葉 豪; 山田 幸生; 星 詳子; 小林 一道; 渡部 正夫
    Proceedings of the 9th International Symposium on Radiative Transfer, RAD-19, SM05号, 掲載ページ 261-268, 出版日 2019年09月, 査読付
    研究論文(国際会議プロシーディングス), 英語
  • Numerical errors of light propagation in the two-dimensional human neck model using the time-dependent radiative transfer equation with renormalized phase functions
    藤井 宏之; 山田 幸生; 星 詳子; 小林 一道; 渡部 正夫
    AIP Conference Proceedings (ICNAAM2018), 2116巻, 450037号, 掲載ページ 1-4, 出版日 2019年07月, 査読付
    研究論文(国際会議プロシーディングス), 英語
  • Effects of Aging, Cognitive Dysfunction, Brain Atrophy on Hemoglobin Concentrations and Optical Pathlength at Rest in the Prefrontal Cortex: A Time-Resolved Spectroscopy Study
    Kaoru Sakatani; Lizhen Hu; Katsunori Oyama; Yukio Yamada
    Applied Sciences, MDPI, Vol. 9巻, Paper No. 2209号, 掲載ページ 1-11, 出版日 2019年05月, 査読付
    研究論文(学術雑誌), 英語
  • Light propagation models of the human neck for photoacoustic imaging of thyroid cancer
    田林 孝介; 藤井 宏之; 大川 晋平; 小林 一道; 山田 幸生; 星 詳子; 渡部 正夫
    CMBE Proceedings (6th International Conference on Computational & Mathematical Biomedical Engineering), A5号, 掲載ページ 161-164, 出版日 2019年05月, 査読付
    研究論文(国際会議プロシーディングス), 英語
  • Time-Domain Near-Infrared Spectroscopy and Imaging: A Review
    Yukio Yamada; Hiroaki Suzuki; Yutaka Yamashita
    Applied Sciences, MDPI, Vol. 9巻, Paper No. 1127号, 掲載ページ 1-53, 出版日 2019年03月, 査読付, 招待
    研究論文(学術雑誌), 英語
  • Accurate and efficient computation of the 3D radiative transfer equation in highly forward-peaked scattering media using a renormalization approach
    藤井 宏之; 山田 幸生; 千葉 豪; 星 詳子; 小林 一道; 渡部 正夫
    Journal of Computational Physics, 374巻, 掲載ページ 591-604, 出版日 2018年12月, 査読付
    研究論文(学術雑誌), 英語
  • Near-infrared temperature measurement technique for water surrounding an induction-heated small magnetic sphere
    Naoto Kakuta; Keisuke Nishijima; van Cuong Han; Yuki Arakawa; Katsuya Kondo; Yukio Yamada
    Journal of Visualized Experiments, Journal of Visualized Experiments, 2018巻, 134号, 掲載ページ 1-10, 出版日 2018年04月30日, 査読付, A technique to measure the temperature of water and non-turbid aqueous media surrounding an induction-heated small magnetic sphere is presented. This technique utilizes wavelengths of 1150 and 1412 nm, at which the absorption coefficient of water is dependent on temperature. Water or a non-turbid aqueous gel containing a 2.0-mm- or 0.5-mm-diameter magnetic sphere is irradiated with 1150 nm or 1412 nm incident light, as selected using a narrow bandpass filter
    additionally, two-dimensional absorbance images, which are the transverse projections of the absorption coefficient, are acquired via a near-infrared camera. When the three-dimensional distributions of temperature can be assumed to be spherically symmetric, they are estimated by applying inverse Abel transforms to the absorbance profiles. The temperatures were observed to consistently change according to time and the induction heating power.
    研究論文(学術雑誌), 英語
  • Light propagation model of titanium dioxide suspensions in water using the radiative transfer equation
    H. Fujii; Y. Yamada; Y. Hoshi; S. Okawa; K. Kobayashi; M. Watanabe
    Reaction Kinetics, Mechanisms and Catalysis, 123巻, 2号, 掲載ページ 439-453, 出版日 2018年04月, 査読付
    研究論文(学術雑誌), 英語
  • Measurement of temperature-dependent diffusion coefficients of aqueous solutions by near-infrared simultaneous imaging of temperature and concentration
    Hiroki Yamashita; Naoto Kakuta; Daisuke Kawashima; Yukio Yamada
    Biomedical Physics and Engineering Express, Institute of Physics, 4巻, 3号, 掲載ページ 1-12, 出版日 2018年04月, 査読付, © 2018 IOP Publishing Ltd. The diffusion coefficients of methanol, ethanol, ethylene glycol, and glucose in water, and their temperature dependence are measured by analysing the simultaneously acquired temperature and concentration images. Simultaneous imaging is achieved using two wavelengths, 1905 nm and 1935 nm, in the ν 2 + ν 3 absorption band of water. In the band, the absorbance at 1905 nm is the most sensitive to temperature, whereas that at 1935 nm is independent of the temperature but strongly dependent on the concentration. To measure the diffusion coefficients, the time evolutions of the diffusion lengths are obtained by fitting the analytical solutions of the two-dimensional steady-state diffusion equation to the transverse concentration profiles in a Y-shaped microfluidic channel. The measured diffusion coefficients and their temperature dependence are verified by comparison with literature values.
    研究論文(学術雑誌), 英語
  • Aspiration Risk Detection Using Oral Administration of Fluorescent Food --- Preliminary Experiments Using Meat Phantoms ---
    Takahiro SUZUKI; Ryohei SAITO; Nobuo KITADA; Takuji KOIKE; Shojiro MAKI; Yukihiro MICHIWAKI; Goro NISHIMURA; Haruki NIWA; Yukio YAMADA
    2017 IEEE International Conference on Cyborg and Bionic Systems (CBS 2017), IEEE, 1巻, 出版日 2017年10月17日, 査読付
    研究論文(国際会議プロシーディングス), 英語
  • Near-infrared measurement of water temperature near a 1-mm-diameter magnetic sphere and its heat generation rate under induction heating
    Naoto Kakuta; Keisuke Nishijima; Katsuya Kondo; Yukio Yamada
    JOURNAL OF APPLIED PHYSICS, AMER INST PHYSICS, 122巻, 4号, 出版日 2017年07月, 査読付, This paper presents a method of measuring the temperature of water near a 1-mm-diameter magnetic sphere under induction heating. The method is based on the temperature dependence of the absorption coefficient of water at a wavelength of 1150 nm. In this study, two-dimensional images of the absorbance, which is the transverse projection of the absorption coefficient of water, were acquired by a near-infrared camera through a telecentric lens, and three-dimensional radial profiles of the temperature were then generated by applying inverse Abel transforms (IATs) to the absorbance profiles. To ensure the spherical symmetry of the temperature and the parallelity of the light rays, which are the conditions necessary to apply an IAT, the onset of free convection and the angles of deflection were evaluated. This paper also presents a method of estimating the heat generation rate in a sphere by fitting the numerical solutions of the thermal conduction equation to the measured temperatures. The temperatures and heat generation rates were observed to change consistently with the changes in the magnetic field intensity. Published by AIP Publishing.
    研究論文(学術雑誌), 英語
  • Modeling of light propagation in the human neck for diagnoses of thyroid cancers by diffuse optical tomography
    H. Fujii; Y. Yamada; K. Kobayashi; M. Watanabe; Y. Hoshi
    INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING, WILEY, 33巻, 5号, 出版日 2017年05月, 査読付, Diffuse optical tomography using near-infrared light in a wavelength range from 700 to 1000nm has the potential to enable non-invasive diagnoses of thyroid cancers; some of which are difficult to detect by conventional methods such as ultrasound tomography. Diffuse optical tomography needs to be based on a physically accurate model of light propagation in the neck, because it reconstructs tomographic images of the optical properties in the human neck by inverse analysis. Our objective here was to investigate the effects of three factors on light propagation in the neck using the 2D time-dependent radiative transfer equation: (1) the presence of the trachea, (2) the refractive-index mismatch at the trachea-tissue interface, and (3) the effect of neck organs other than the trachea (spine, spinal cord, and blood vessels). There was a significant influence of reflection and refraction at the trachea-tissue interface on the light intensities in the region between the trachea and the front of the neck surface. Organs other than the trachea showed little effect on the light intensities measured at the front of the neck surface although these organs affected the light intensities locally. These results indicated the necessity of modeling the refractive-index mismatch at the trachea-tissue interface and the possibility of modeling other neck organs simply as a homogeneous medium when the source and detectors were far from large blood vessels.
    研究論文(学術雑誌), 英語
  • Normalization method of highly forward-peaked scattering phase function using the double exponential formula for radiative transfer
    藤井 宏之; 大川 晋平; 山田 幸生; 星 詳子; 渡部 正夫
    AIP Conference Proceedings (ICCMSE2016), 1790巻, 050002号, 掲載ページ 1-4, 出版日 2016年12月, 査読付
    研究論文(国際会議プロシーディングス), 英語
  • Renormalization of the highly forward-peaked phase function using the double exponential formula for radiative transfer
    Hiroyuki Fujii; Shinpei Okawa; Yukio Yamada; Yoko Hoshi; Masao Watanabe
    JOURNAL OF MATHEMATICAL CHEMISTRY, SPRINGER, 54巻, 10号, 掲載ページ 2048-2061, 出版日 2016年11月, 査読付, Numerical calculation of photon migration in biological tissue using the radiative transfer equation (RTE) has attracted great interests in biomedical optics and imaging. Because biological tissue is a highly forward-peaked scattering medium, renormalization of the phase function in numerical calculation of the RTE is crucial. This paper proposes a simple approach of renormalizing the phase function by the double exponential formula, which was heuristically modified from the original one. Firstly, the validity of the proposed approach was tested by comparing numerical results for an average cosine of the polar scattering angle calculated by the proposed approach with those by the conventional approach in highly forward-peaked scattering. The results show that calculation of the average cosine converged faster using the proposed approach than using the conventional one as a total number of discrete angular directions increases. Next, the accuracy of the numerical solutions of the RTE using the proposed approach was examined by comparing the numerical solutions with the analytical solutions of the RTE in a homogeneous medium with highly forward-peaked scattering. It was found that the proposed approach reduced the errors of the numerical solutions from those using the conventional one especially at a small value of the total number of the directions. This result suggests that the proposed approach has a possibility to improve the accuracy for the numerical results of the RTE in the highly scattering medium.
    研究論文(学術雑誌), 英語
  • Simultaneous imaging of temperature and concentration of ethanol–water mixtures in microchannel using near-infrared dual-wavelength absorption technique
    Naoto Kakuta; Hiroki Yamashita; Daisuke Kawashima; Katsuya Kondo; Hidenobu Arimoto; Yukio Yamada
    Measurement Science and Technology, IOP Publishing, 27巻, 11号, 掲載ページ 1-12, 出版日 2016年11月, 査読付, This paper presents a simultaneous imaging method of temperature and ethanol concentration of ethanol-water mixtures in microfluidic channels. The principle is based on the facts that the absorbance at a wavelength of 1905 nm is dependent on the temperature of water and that the absorbance at 1935 nm is independent of the temperature but strongly dependent on the molar concentration of water, which is reciprocal to the molar concentration of ethanol in the mixture. The absorbance images at the two wavelengths were acquired alternately, each at 50 frames per second, by an alternate irradiation system and near-infrared (NIR) camera, and then converted to the temperature and concentration images by a linear regression model. The imaging method was applied to a dilute ethanol-water mixture with an ethanol concentration of 0.43M and water flowing side by side in a temperature-controlled Y-channel. The concentration images clearly showed differences between the mixture and water streams, and that the transverse concentration gradient between the two streams decreased downstream by mutual diffusion. It was also confirmed that the mutual diffusion coefficient increased as the temperature increased. The temperature images showed that uniform distributions were immediately formed due to heat transfer between the fluid and channel materials.
    研究論文(学術雑誌), 英語
  • Overview of diffuse optical tomography and its clinical applications
    Yoko Hoshi; Yukio Yamada
    JOURNAL OF BIOMEDICAL OPTICS, SPIE-SOC PHOTO-OPTICAL INSTRUMENTATION ENGINEERS, 21巻, 9号, 掲載ページ 091312-1-091312-12, 出版日 2016年09月, 査読付, 招待, Near-infrared diffuse optical tomography (DOT), one of the most sophisticated optical imaging techniques for observations through biological tissue, allows 3-D quantitative imaging of optical properties, which include functional and anatomical information. With DOT, it is expected to be possible to overcome the limitations of conventional near-infrared spectroscopy (NIRS) as well as offering the potential for diagnostic optical imaging. However, DOT has been under development for more than 30 years, and the difficulties in development are attributed to the fact that light is strongly scattered and that diffusive photons are used for the image reconstruction. The DOT algorithm is based on the techniques of inverse problems. The radiative transfer equation accurately describes photon propagation in biological tissue, while, because of its high computation load, the diffusion equation (DE) is often used as the forward model. However, the DE is invalid in low-scattering and/or highly absorbing regions and in the vicinity of light sources. The inverse problem is inherently ill-posed and highly undetermined. Here, we first summarize NIRS and then describe various approaches in the efforts to develop accurate and efficient DOT algorithms and present some examples of clinical applications. Finally, we discuss the future prospects of DOT. (C) The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication
    研究論文(学術雑誌), 英語
  • 近赤外域の単一波長を利用した中和反応で生成する塩濃度の可視化
    川嶋 大介; 角田 直人; 有本 英伸; 近藤 克哉; 山田 幸生
    可視化情報学会論文集, 社団法人 可視化情報学会, 36巻, 12号, 掲載ページ 62-70, 出版日 2016年,

    本論文では,マイクロ流路チップ内において酸・アルカリ水溶液の中和反応より生成する塩濃度を可視化するため,近赤外域の単一波長を利用した新しいイメージング技術を提案する.本イメージング法は,水のν1+ν3吸収バンド内にある波長1520 nmの吸収特性を利用する.波長1520 nmは,酸やアルカリ水溶液特有の等吸収点であり,これらの溶質濃度の増減によって吸光度が変化しない.一方,塩濃度に関しては吸収感度があるため,この波長の吸光度測定により塩濃度を見積もることができる.単一波長を利用した本手法を評価するため,T字型マイクロ流路を用いて,(i)水とNaClの混合および(ii) 塩酸と水酸化ナトリウム水溶液の反応拡散の2条件についてNaCl濃度の可視化実験を行った.測定したNaCl濃度は数値解析結果と比較してよく一致しており,提案手法の有効性を示した.


    英語
  • Numerical modeling of photon migration in human neck based on the radiative transport equation
    Hiroyuki Fujii; Shinpei Okawa; Ken Nadamoto; Eiji Okada; Yukio Yamada; Yoko Hoshi; Masao Watanabe
    Journal of Applied Nonlinear Dynamics, L and H Scientific Publishing, LLC, 5巻, 1号, 掲載ページ 117-125, 出版日 2016年, 査読付, Biomedical optical imaging has a possibility of a comprehensive di- agnosis of thyroid cancer in conjunction with ultrasound imaging. For improvement of the optical imaging, this study develops a higher order scheme for solving the time-dependent radiative transport equa- tion (RTE) by use of the finite-difference and discrete-ordinate meth- ods. The accuracy and efficiency of the developed scheme are ex- amined by comparison with the analytical solutions of the RTE in homogeneous media. Then, the developed scheme is applied to de- scribing photon migration in the human neck model. The numerical simulations show complex behaviors of photon migration in the hu- man neck model due to multiple diffusive reflection near the trachea.
    研究論文(学術雑誌), 英語
  • Numerical analysis of photon migration in three-dimensional turbid media using the delta-Eddington approximation
    Hiroyuki Fujii; Shinpei Okawa; Ken Nadamoto; Eiji Okada; Yukio Yamada; Yoko Hoshi; Masao Watanabe
    Proceedings of the 9th ICME International Conference on Complex Medical Engineering (CME 2015), ICME, 1巻, 1号, 掲載ページ 1-2, 出版日 2015年06月19日, 査読付, 招待
    研究論文(国際会議プロシーディングス), 英語
  • Near-infrared noninvasive blood glucose prediction without using multivariate analyses: introduction of imaginary spectra due to scattering change in the skin
    Katsuhiko Maruo; Yukio Yamada
    JOURNAL OF BIOMEDICAL OPTICS, SPIE-SOC PHOTO-OPTICAL INSTRUMENTATION ENGINEERS, 20巻, 4号, 掲載ページ No. 047003-No. 047003, 出版日 2015年04月, 査読付, A noninvasive measurement method is proposed and examined to continuously predict blood glucose contents using near-infrared diffuse reflection difference spectra measured at the skin tissue without using multivariate analyses. Using the modified Beer's law, the difference spectra are assumed to be synthesized from four major components in the human skin (water, protein, glucose, and fat) and a scattering equivalent component called baseline. As a result, one of the origins of the errors in blood glucose prediction using near-infrared is found to be the similarity of the shapes of the absorption spectrum between glucose and baseline. After separating the glucose contributions from the difference spectra at the characteristic wavelengths of baseline and fat, an imaginary component combining baseline and fat is introduced by considering that both the change in the fat contribution and the generation of baseline originate from the change in scattering in the skin. The imaginary component enables us to reduce the errors in blood glucose prediction. In contrast to the methods using multivariate analyses, the calculation process of the blood glucose contents from the measured reflection spectra is clear in this method, thus, it is easy to estimate the origins of the changes and contributions of the components in the measured difference spectra. The proposed method may become a useful tool for realization of noninvasive blood glucose prediction using near-infrared spectroscopy. (C) 2015 Society of Photo-Optical Instrumentation Engineers (SPIE)
    研究論文(学術雑誌), 英語
  • Numerical modeling of photon migration in the cerebral cortex of the living rat using the radiative transport equation
    藤井 宏之; 大川 晋平; 灘本 健; 岡田 英史; 山田 幸生; 星 詳子; 渡部 正夫
    Proceedings of SPIE, Biomedical Applications of Light Scattering IX, 9333巻, 933313号, 掲載ページ 1-6, 出版日 2015年03月, 査読付
    研究論文(国際会議プロシーディングス), 英語
  • A coupling model of the radiative transport equation for calculating photon migration in biological tissue
    Hiroyuki Fujii; Shinpei Okawa; Yukio Yamada; Yoko Hoshi; Masao Watanabe
    Progress in Biomedical Optics and Imaging - Proceedings of SPIE, SPIE, 9792巻, 出版日 2015年, 査読付, Development of a physically accurate and computationally efficient photon migration model for turbid media is crucial for optical computed tomography such as diffuse optical tomography. For the development, this paper constructs a space-time coupling model of the radiative transport equation with the photon diffusion equation. In the coupling model, a space-time regime of the photon migration is divided into the ballistic and diffusive regimes with the interaction between the both regimes to improve the accuracy of the results and the efficiency of computation. The coupling model provides an accurate description of the photon migration in various turbid media in a wide range of the optical properties, and reduces computational loads when compared with those of full calculation of the RTE.
    研究論文(国際会議プロシーディングス), 英語
  • A coupling model of the radiative transport equation for calculating photon migration in biological tissue
    Hiroyuki Fujii; Shinpei Okawa; Yukio Yamada; Yoko Hoshi; Masao Watanabe
    BIOPHOTONICS JAPAN 2015, SPIE-INT SOC OPTICAL ENGINEERING, 9792巻, Paper No. 979214号, 掲載ページ 1-5, 出版日 2015年, 査読付, Development of a physically accurate and computationally efficient photon migration model for turbid media is crucial for optical computed tomography such as diffuse optical tomography. For the development, this paper constructs a space-time coupling model of the radiative transport equation with the photon diffusion equation. In the coupling model, a space-time regime of the photon migration is divided into the ballistic and diffusive regimes with the interaction between the both regimes to improve the accuracy of the results and the efficiency of computation. The coupling model provides an accurate description of the photon migration in various turbid media in a wide range of the optical properties, and reduces computational loads when compared with those of full calculation of the RTE.
    研究論文(国際会議プロシーディングス), 英語
  • Hybrid model of light propagation in random media based on the time-dependent radiative transfer and diffusion equations
    Hiroyuki Fujii; Shinpei Okawa; Yukio Yamada; Yoko Hoshi
    JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER, PERGAMON-ELSEVIER SCIENCE LTD, 147巻, 掲載ページ 145-154, 出版日 2014年11月, 査読付, Numerical modeling of light propagation in random media has been an important issue for biomedical imaging, including diffuse optical tomography (DOT). For high resolution DOT, accurate and fast computation of light propagation in biological tissue is desirable. This paper proposes a space-time hybrid model for numerical modeling based on the radiative transfer and diffusion equations (RTE and DE, respectively) in random media under refractive-index mismatching. In the proposed model, the RTE and DE regions are separated into space and time by using a crossover length and the time from the ballistic regime to the diffusive regime, rho(DA) similar to 10/mu(t)' and t(DA) similar to 20/v mu(t)' where mu(t)' and v represent a reduced transport coefficient and light velocity, respectively. The present model succeeds in describing light propagation accurately and reduces computational load by a quarter compared with full computation of the RTE. (C) 2014 Elsevier Ltd. All rights reserved.
    研究論文(学術雑誌), 英語
  • Reconstruction of cross-sectional temperature distributions of water around a thin heating wire by inverse Abel transform of near-infrared absorption images
    Naoto Kakuta; Katsuya Kondo; Hidenobu Arimoto; Yukio Yamada
    INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER, PERGAMON-ELSEVIER SCIENCE LTD, 77巻, 掲載ページ 852-859, 出版日 2014年10月, 査読付, A reconstruction method of temperature distributions of water around a thin heating wire is presented. This method is based on the temperature dependence of the absorption coefficient of water at the wavelength of 1412 nm. In the case that the temperature distribution is assumed to be axisymmetric with respect to the wire, this radial distribution can be determined by applying the inverse Abel transform (IAT) to a one-dimensional profile of the absorbance which is the projection of the absorption coefficient. To perform the IAT robustly, the measured absorbance profiles are approximated by multi-Gaussian functions because the IATs of these functions are obtained analytically. This paper shows a time series of cross-sectional temperature images of water around a heating wire with a diameter of 0.05 mm. They clearly indicate changes in the temperature distribution with a resolution of less than 0.1 K when the heat generation rate varies. These results are verified by comparison with numerically simulated results. (C) 2014 Elsevier Ltd. All rights reserved.
    研究論文(学術雑誌), 英語
  • A 3D-visualization of fluorescence target in deep human tissue by means of time-domain optical tomography
    Goro Nishimura; Yukio Yamada; Hideo Saji; Yasuomi Ouchi
    Transactions of Japanese Society for Medical and Biological Engineering, Japan Soc. of Med. Electronics and Biol. Engineering, 52巻, 掲載ページ 62-SY-63, 出版日 2014年08月17日, 査読付, It is difficult to visualize the fluorescence object buried into the biological tissue more than a few millimeters deep due to the strong scattering and absorption properties. To recover the lost spatial information, we have studied on a 3-dimensional reconstruction using data from time-domain measurements of the fluorescence and excitation. In this study, we have employed a method, fluorescence-assisted diffuse optical tomography (FA-DOT), to quantify the absorption of the fluorescence object. We also have developed a simple targeting method for the practical way in clinical application. We conducted some phantom measurements to clarify the experimental artifact and analyze the effect on the reconstruction to establish the robust 3D reconstruction method.
    研究論文(学術雑誌), 英語
  • Temperature Imaging of Water Around a Small Heated Sphere Using a Nera-Infrared Absorption Technique
    Naoto Kakuta; Kenta Yamada; Ryota Fujioka; Katsuya Kondo; Hidenobu Armoto; Yukio Yamada
    The 15th International Heat Transfer Conference, Proceedings巻, 出版日 2014年08月10日, 査読付
    研究論文(国際会議プロシーディングス), 英語
  • Reconstruction of localized fluorescent target from multi-view continuous-wave surface images of small animal with l(p) sparsity regularization
    Shinpei Okawa; Tatsuya Ikehara; Ichiro Oda; Yukio Yamada
    BIOMEDICAL OPTICS EXPRESS, OPTICAL SOC AMER, 5巻, 6号, 掲載ページ 1839-1860, 出版日 2014年06月, 査読付, Fluorescence diffuse optical tomography using a multi-view continuous-wave and non-contact measurement system and an algorithm incorporating the l(p) (0 < p <= 1) sparsity regularization reconstructs a localized fluorescent target in a small animal. The measurement system provides a total of 25 fluorescence surface 2D-images of an object, which are acquired by a CCD camera from five different angles of view with excitation from five different angles. Fluorescence surface emissions from five different angles of view are simultaneously imaged on the CCD sensor, thus leading to fast acquisition of the 25 images within three minutes. The distributions of the fluorophore are reconstructed by solving the inverse problem based on the photon diffusion equations. In the reconstruction process incorporating the lp sparsity regularization, the regularization term is reformulated as a differentiable function for gradient-based non-linear optimization. Numerical simulations and phantom experiments show that the use of the l(p) sparsity regularization improves the localization of the target and quantitativeness of the fluorophore concentration. A mouse experiment demonstrates that a localized fluorescent target in a mouse is successfully reconstructed. (C) 2014 Optical Society of America
    研究論文(学術雑誌), 英語
  • Diffuse Optical Tomography: Present Status and Its Future
    Yukio Yamada; Shinpei Okawa
    OPTICAL REVIEW, OPTICAL SOC JAPAN, 21巻, 3号, 掲載ページ 185-205, 出版日 2014年05月, 査読付, 招待, Diffuse optical tomography (DOT) is one of the emerging modalities for the non-invasive imaging of thick biological tissues using near-infrared (NIR) light. This article reviews the fundamentals and development of DOT technology since its advent in the early 1990s, including the modeling of light propagation in biological tissues which strongly scatter and weakly absorb NIR light, the optical properties of biological tissues in the NIR wavelength range, three typical measurement methods, image reconstruction algorithms, and so forth. Then various studies are referred to for improvement of the DOT images, which are essentially low in quality due to the ill-conditioned and underdetermined problem. Studies and clinical applications presently attracting much attention are discussed in some detail. Finally, the expected future developments are summarized. (C) 2014 The Japan Society of Applied Physics
    研究論文(学術雑誌), 英語
  • Understanding near infrared radiation propagation in pig skin reflectance measurements
    Eduardo Zamora-Rojas; Ana Garrido-Varo; Ben Aernouts; Dolores Perez-Marin; Wouter Saeys; Yukio Yamada; Jose Emilio Guerrero-Ginel
    INNOVATIVE FOOD SCIENCE & EMERGING TECHNOLOGIES, ELSEVIER SCI LTD, 22巻, 掲載ページ 137-146, 出版日 2014年04月, 査読付, Non-invasive and non-destructive analysis based on Near Infrared Reflectance Spectroscopy (NIRS) sensors are used for the development of quality control systems in numerous in situ/on-line applications in different fields. However, few studies have been published investigating and trying to understand how light propagates through agri-food tissues. In this paper, diffuse reflectance spectra of Iberian pig skin were simulated for different source-detector distances in the wavelength range from 1150 nm to 1850 nm. The average photon visit depth and the fraction of absorbed energy indicated that most of the light was absorbed by the dermis layer. Nevertheless, larger source-detector distances enabled to acquire information from deeper in the skin tissue and to maximize the sensitivity of the captured signal to the subcutaneous adipose tissue. These simulation results were experimentally validated using spatially resolved reflectance spectroscopy, and a good agreement was obtained between the simulations and measurements.
    Industrial relevance: A stochastic approach such as Monte Carlo method is used for investigating and characterizing non-destructive and non-invasive diffuse reflectance NIR spectroscopy measurements of Iberian pigs in the 1150-1850 nm wavelength range. Different source detector distances have been evaluated in order to optimize the optical configuration of NIRS instruments and maximize the spectral information detected from the subcutaneous adipose tissue. This study helps to understand how the light is propagated in pig tissues, which is relevant to design new spectrometers that can be used as non-destructive in situ/in vivo quality control system or support-decision making system. (C) 2014 Elsevier Ltd. All rights reserved.
    研究論文(学術雑誌), 英語
  • Image errors of time-resolved optical tomography based on the radiative transfer and diffusion equations
    藤井宏之; 大川晋平; 吉永哲哉; 山田幸生; 星詳子
    ODF'14 Technical Digest (9th International Conference on Optics-photonics Design and Fabrication), 13PDb-20巻, 掲載ページ 1-2, 出版日 2014年02月, 査読付
    研究論文(国際会議プロシーディングス), 英語
  • cortex
    Rei Murata; Yuki Takada; Hiroyuki Takuwa; Hiroshi Kawaguchi; Hiroshi Ito; Iwao Kanno; Naotomo Tottori; Yukio Yamada; Yutaka Tomita; Yoshiaki Itoh; Norihiro Suzuki; Katsuya Yamada; Kazuto Masamoto
    Advances in Experimental Medicine and Biology, Springer New York LLC, 812巻, 掲載ページ 241-246, 出版日 2014年, 査読付, The present study examined glucose transfer in the cellular scale of mouse brain microvasculature in vivo using two-photon microscopy and fl uorescent glucose analogue (2-NBDG). The 2-NBDG was intravenously injected (0.04 mL/ min) in the anesthetized Tie2-GFP mice in which the vascular endothelium expressed fl uorescent protein. Time-lapse imaging was conducted on the cortical parenchyma, while the time–intensity change of the injected 2-NBDG was analysed in respective vascular compartments (artery, capillary, and vein). We observed that 2-NBDG signal increased monotonically in the vasculature during the period of the injection, and rapidly declined following its cessation. In tissue compartment, however, the signal intensity gradually increased even after cessation of the injection. Spatiotemporal analysis of the 2-NBDG intensity over the cross-sections of the vessels further showed distinct change of the 2-NBDG intensity across the vessel wall (endothelium), which may represents a regulation site of tissue glucose infl ux.
    研究論文(学術雑誌), 英語
  • Vessel Specific Imaging of Glucose Transfer with Fluorescent Glucose Analogue in Anesthetized Mouse Cortex
    Rei Murata; Yuki Takada; Hiroyuki Takuwa; Hiroshi Kawaguchi; Hiroshi Ito; Iwao Kanno; Naotomo Tottori; Yukio Yamada; Yutaka Tomita; Yoshiaki Itoh; Norihiro Suzuki; Katsuya Yamada; Kazuto Masamoto
    OXYGEN TRANSPORT TO TISSUE XXXVI, SPRINGER, 812巻, 掲載ページ 241-246, 出版日 2014年, 査読付, The present study examined glucose transfer in the cellular scale of mouse brain microvasculature in vivo using two-photon microscopy and fluorescent glucose analogue (2-NBDG). The 2-NBDG was intravenously injected (0.04 mL/min) in the anesthetized Tie2-GFP mice in which the vascular endothelium expressed fluorescent protein. Time-lapse imaging was conducted on the cortical parenchyma, while the time-intensity change of the injected 2-NBDG was analysed in respective vascular compartments (artery, capillary, and vein). We observed that 2-NBDG signal increased monotonically in the vasculature during the period of the injection, and rapidly declined following its cessation. In tissue compartment, however, the signal intensity gradually increased even after cessation of the injection. Spatiotemporal analysis of the 2-NBDG intensity over the cross-sections of the vessels further showed distinct change of the 2-NBDG intensity across the vessel wall (endothelium), which may represents a regulation site of tissue glucose influx.
    研究論文(学術雑誌), 英語
  • Automated Image Analysis for Diameters and Branching Points of Cerebral Penetrating Arteries and Veins Captured with Two-Photon Microscopy
    Takuma Sugashi; Kouichi Yoshihara; Hiroshi Kawaguchi; Hiroyuki Takuwa; Hiroshi Ito; Iwao Kanno; Yukio Yamada; Kazuto Masamoto
    OXYGEN TRANSPORT TO TISSUE XXXVI, SPRINGER, 812巻, 掲載ページ 209-215, 出版日 2014年, 査読付, The present study was aimed to characterize 3-dimensional (3D) morphology of the cortical microvasculature (e. g., penetrating artery and emerging vein), using two-photon microscopy and automated analysis for their cross-sectional diameters and branching positions in the mouse cortex. We observed that both artery and vein had variable cross-sectional diameters across cortical depths. The mean diameter was similar for both artery (17 +/- 5 mu m) and vein (15 +/- 5 mu m), and there were no detectable differences over depths of 50-400 mu m. On the other hand, the number of branches was slightly increased up to 400-mu m depth for both the artery and vein. The mean number of branches per 0.1 mm vessel length was 1.7 +/- 1.2 and 3.8 +/- 1.6 for the artery and vein, respectively. This method allows for quantification of the large volume data of microvascular images captured with two-photon microscopy. This will contribute to the morphometric analysis of the cortical microvasculature in functioning brains.
    研究論文(学術雑誌), 英語
  • Visualization and analysis of heat and mass transfer with chemical reactions in microchannels
    D. Kawashima; N. Kakuta; K. Kondo; H. Arimoto; Y. Yamada
    Proceedings of the 15th International Heat Transfer Conference, IHTC 2014, Proceedings巻, 出版日 2014年, 査読付, Micro-sensing techniques of temperature and concentration are essential to investigate mixing, chemical reaction, and matter generation processes in micro-reactor technology. We have developed a simultaneous imaging method of the temperature and solute concentrations of aqueous solutions in microchannels using two different wavelengths in near-infrared (NIR); one is 1412 nm at which the absorbance is sensitive to the temperature of water and the other is 1442 nm at which the absorbance is insensitive to the temperature and dependent only upon solute concentrations. In this study, when two aqueous solutions of hydrochloric acid (HCl) and sodium hydroxide (NaOH) flow at a flow rate of 60 μL·min-1 and merge in a Y-shaped channel with a depth of 0.5 mm, absorption variations at the two wavelengths are investigated. The absorbance difference images indicate that the concentrations ratio of the two solutions determine the merging condition. Particularly in the case that the molar fraction of hydrochloric acid is 0.67 (HCl:NaOH = 2 M: 1 M), an interface between the solutions is formed. The interface, however, disappears and mixture area appears at the other molar fractions. Also, the absorbance images is converted to solute concentration ones of HCl and NaOH by a multiple regression analysis on the absorbance difference spectra of the two solutions.
    研究論文(国際会議プロシーディングス), 英語
  • 水の近赤外吸収特性を利用した非接触温度イメージング
    角田直人; 近藤克哉; 有本英伸; 山田幸生
    システム制御情報学会誌, Japan Society of Physiological Anthropology, 57巻, 12号, 掲載ページ 493-498, 出版日 2013年12月, 査読付, In order to predict airflow and suspended substance concentration around a human body, we developed a geometric model of the human form and generated grids around it for Computational Fluid Dynamics (CFD). According to a CFSV model proposed by us we made a domain that included a geometric human model and generated the grids within this domain. By using this model with the grids and the developed CFD program, it is possible to simulate the airflow and the transfer of a suspended substance around the body. The simulated airflow provided a different velocity profile for each region of the body due to the characteristics of the body shape. The simulated distribution of the suspended substance concentration demonstrates how usable the present model is for quantifying a substance in any exposed region of the body. J Physiol Anthropol 21 (5): 215-222, 2002 http://www.jstage.jst.go.jp/en/
    研究論文(学術雑誌), 日本語
  • Phantom and mouse experiments of time-domain fluorescence tomography using total light approach
    Shinpei Okawa; Akira Yano; Kazuki Uchida; Yohei Mitsui; Masaki Yoshida; Masashi Takekoshi; Andhi Marjono; Feng Gao; Yoko Hoshi; Ikuhiro Kida; Kazuto Masamoto; Yukio Yamada
    BIOMEDICAL OPTICS EXPRESS, OPTICAL SOC AMER, 4巻, 4号, 掲載ページ 635-651, 出版日 2013年04月, 査読付, Phantom and mouse experiments of time-domain fluorescence tomography were conducted to demonstrate the total light approach which was previously proposed by authors. The total light approach reduces the computation time to solve the forward model for light propagation. Time-resolved temporal profiles were acquired for cylindrical phantoms having single or double targets containing indocyanine green (ICG) solutions. The reconstructed images of ICG concentration reflected the true distributions of ICG concentration with a spatial resolution of about 10 mm. In vivo experiments were conducted using a mouse in which an ICG capsule was embedded beneath the skin in the abdomen. The reconstructed image of the ICG concentration again reflected the true distribution of ICG although artifacts due to autofluorescence appeared in the vicinity of the skin. The effectiveness of the total light approach was demonstrated by the phantom and mouse experiments. (C) 2013 Optical Society of America
    研究論文(学術雑誌), 英語
  • A coupling model of light propagation based on the radiative transfer and diffusion equations
    藤井 宏之; 星 詳子; 大川 晋平; 吉永 哲哉; 河野 理; 山田 幸生
    AIP Conference Proceedings (ICNAAM 2013), 1558巻, 掲載ページ 2528-2531, 出版日 2013年, 査読付, Recently, transport phenomena of photon energy have been attractive topics due to the applications of the biomedical imaging such as diffuse optical tomography (DOT). For improvement of numerical modeling in DOT, accurate and fast calculations of light propagations in biological tissues are necessary. This paper proposes a light propagation model based on the radiative transfer and diffusion equations (RTE and DE) in random media. Numerical calculations of light propagation using the both equations provide the condition for the DE to be valid. Length and time scales for the validity of the DE are estimated to be about 10lm and 20lm/ν, respectively, where l m is the mean free path of photon and v is the light velocity. The proposed model can provide accurate descriptions of spatial and temporal profiles of light propagation in random media subject to the refractive-index mismatched boundary condition. Also, it can appropriately reduce computation time by an order of magnitude when compared with that fully computing the RTE. © 2013 AIP Publishing LLC.
    研究論文(国際会議プロシーディングス), 英語
  • In vivo Time-resolved DOT measurement and image reconstruction of human forearm under exercises
    Y. Tanikawa; F. Gao; M. Miyakawa; T. Kiryu; T. Kizuka; S. Okawa; Y. Yamada
    2013 35TH ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY (EMBC), IEEE, Proceedings巻, 掲載ページ 1811-1814, 出版日 2013年, 査読付, In vivo measurement of time-resolved diffuse optical tomography (TR-DOT) were performed for human forearms under the exercises. The DOT images of oxygenation state were reconstructed, and the activities of the inner muscles were assessed.
    研究論文(国際会議プロシーディングス), 英語
  • Influences of Blood Flow Changes in Cerebrospinal Fluid and Skin Layers on Optical Mapping
    Shuping Wang; Yoko Hoshi; Yukio Yamada
    2013 35TH ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY (EMBC), IEEE, Proceedings巻, 掲載ページ 2632-2635, 出版日 2013年, 査読付, In optical mapping for imaging brain activity, the effect of blood flow changes in superficial tissues such as the cerebrospinal fluid (CSF) and skin layers should be considered. However, it is difficult to know those changes in in vivo experiments. To investigate the influence of blood flow changes in CSF and skin layers on optical mapping, we perform numerical simulations of optical mapping by solving the photon diffusion equation for layered-models simulating human heads using the finite element method (FEM). The results show that mapping images of activated region in the gray matter layer are affected by the existence of blood vessels in CSF layer and by the blood flow changes in the skin layer. The increases in both the vessel size and vessel absorption coefficient reduce the sensitivity of the mapping images to the brain activity in the gray matter. On the other hand, the increase in the vessel volume fraction in the skin layer increases the sensitivity of the mapping images.
    研究論文(国際会議プロシーディングス), 英語
  • 3D Analysis of Intracortical Microvasculature During Chronic Hypoxia in Mouse Brains
    Kouichi Yoshihara; Hiroyuki Takuwa; Iwao Kanno; Shinpei Okawa; Yukio Yamada; Kazuto Masamoto
    OXYGEN TRANSPORT TO TISSUE XXXIV, SPRINGER, 765巻, 掲載ページ 357-363, 出版日 2013年, 査読付, The purpose of this study is to determine when and where the brain microvasculature changes its network in response to chronic hypoxia. To identify the hypoxia-induced structural adaptation, we longitudinally imaged cortical microvasculature at the same location within a mouse somatosensory cortex with two-photon microscopy repeatedly for up to 1 month during continuous exposure to hypoxia (either 8 or 10% oxygen conditions). The two-photon microscopy approach made it possible to track a 3D pathway from a cortical surface arteriole to a venule up to a depth of 0.8 mm from the cortical surface. The network pathway was then divided into individual vessel segments at the branches, and their diameters and lengths were measured. We observed 3-11 vessel segments between the penetrating arteriole and the emerging vein over the depths of 20-460 mu m within the 3D reconstructed image (0.46 x 0.46 x 0.80 mm(3)). The average length of the individual capillaries (<7 mu m in diameter) was 67 + 46 mu m, which was not in fluenced by hypoxia. In contrast, 1.4 +/- 0.3 and 1.2 +/- 0.2 fold increases of the capillary diameter were observed 1 week after exposure to 8 % and 10% hypoxia, respectively. At 3 weeks from the exposure, the capillary diameter reached 8.5 +/- 1.9 and 6.7 +/- 1.8 mu m in 8% and 10 % hypoxic conditions, respectively, which accounted for the 1.8 +/- 0.5 and 1.4 +/- 0.3 fold increases relative to those of the prehypoxic condition. The vasodilation of penetrating arterioles (1.4 +/- 0.2 and 1.2 +/- 0.2 fold increases) and emerging veins (1.3 +/- 0.2 and 1.3 +/- 0.2 fold increases) showed relatively small diameter changes compared with the parenchymal capillaries. These findings indicate that parenchymal capillaries are the major site responding to the oxygen environment during chronic hypoxia.
    研究論文(学術雑誌), 英語
  • In vivo Time-resolved DOT images of human forearm under exercises
    Yukari Tanikawa; Feng Gao; Michio Miyakawa; Toru Kiryu; Tomohiro Kizuka; Shinpei Okawa; Yukio Yamada
    Functional Near Infrared Spectroscopy Conference, Abstract book, Abstract book巻, 掲載ページ 177-177, 出版日 2012年10月26日, 査読付
    研究論文(国際会議プロシーディングス), 英語
  • Fluorescence diffuse optical tomography of small animals
    Masaki Yoshida; Yohei Mitsui; Masashi Takekoshi; Shinpei Okawa; Yoko Hoshi; Ikuhiro Kida; Kazuto Masamoto; Yukio Yamada
    NanoRad 2012 Abstract Book, NanoRad 2012 Abstract Book巻, 掲載ページ 42-43, 出版日 2012年05月, 査読付
    研究論文(国際会議プロシーディングス), 英語
  • 拡散光トモグラフィーによるヒト前腕筋活動の評価
    谷川 ゆかり; 高 峰; 宮川 道夫; 木竜 徹; 木塚 朝博; 遠藤 泰臣; 大川 晋平; 山田 幸生
    電気学会論文誌C編, 132/Sec. C巻, 3号, 掲載ページ 374-383, 出版日 2012年03月, 査読付
    研究論文(学術雑誌), 日本語
  • Evaluation of muscle activities in human forearms under exercises by diffuse optical tomography
    Yukari Tanikawa; Feng Gao; Michio Miyakawa; Toru Kiryu; Tomohiro Kizuka; Yasuomi Endo; Shinpei Okawa; Yukio Yamada
    IEEJ Transactions on Electronics, Information and Systems, Institute of Electrical Engineers of Japan, 132巻, 3号, 掲載ページ 6-383, 出版日 2012年, 査読付, During the forearm exercise, it is generally understood that the inner muscles work for the task, and the outer muscles work to fix the joints for the efficient work of the inner muscles. For evaluation of the exercise, quantitative measurement of inner muscle activities is necessary. Electromyograph (EMG) and oxygen monitoring using continuous-wave near-infrared spectroscopy (CW-NIRS) have been used for the evaluation because both of them are the modalities of safe, portable and noninvasive measurements of muscle activities. However, these modalities can show the qualitative changes in the muscle activities in the vicinity of the skin surface. Time-resolved diffuse optical tomography (TR-DOT) can quantitatively provide tomographic images of the changes in the oxygenation state of the whole muscles. In vivo experiments of TR-DOT were performed for human forearms under handgrip exercises, and DOT images of the changes in the oxygenation state of the forearms were reconstructed using the algorithm based on the modified generalized pulsed spectrum technique. The DOT images are compared with the MR-images, and it is shown that the activities of the inner muscles of the forearms were active during the handgrip excises. © 2012 The Institute of Electrical Engineers of Japan.
    研究論文(学術雑誌), 英語
  • 拡散光トモグラフィーによる生体内の光学特性値分布の再構成
    大川晋平; 山田幸生
    日本レーザー医学会誌, 32巻, 4号, 掲載ページ 402-410, 出版日 2012年, 査読付
  • 蛍光による生体分子イメージングにおける画像再構成の高度化
    大川晋平; 池原辰弥; 小田一郎; 山田幸生
    光学, 応用物理学会分科会日本光学会, 8巻, 41号, 掲載ページ 424-429, 出版日 2012年, 査読付
    日本語
  • 7D22 Quantitative analysis of micro vascular network structure in the cerebral cortex.
    Takuma SUGASHI; Kouichi YOSHIHARA; Daiki YAMAGUCHI; Daigo SHIRAHATA; Hiroshi KAWAGUCHI; Iwao KANNO; Hiroshi ITO; Shinpei OKAWA; Kazuto MASAMOTO; Yukio YAMADA
    The Proceedings of the Bioengineering Conference Annual Meeting of BED/JSME, Japan Society of Mechanical Engineers, 2012.24巻, 0号, 掲載ページ \_}7D22, 出版日 2012年, 査読付
  • Reduction of Poisson noise in measured time-resolved data for time-domain diffuse optical tomography
    S. Okawa; Y. Endo; Y. Hoshi; Y. Yamada
    MEDICAL & BIOLOGICAL ENGINEERING & COMPUTING, SPRINGER HEIDELBERG, 50巻, 1号, 掲載ページ 69-78, 出版日 2012年01月, 査読付, A method to reduce noise for time-domain diffuse optical tomography (DOT) is proposed. Poisson noise which contaminates time-resolved photon counting data is reduced by use of maximum a posteriori estimation. The noise-free data are modeled as a Markov random process, and the measured time-resolved data are assumed as Poisson distributed random variables. The posterior probability of the occurrence of the noise-free data is formulated. By maximizing the probability, the noise-free data are estimated, and the Poisson noise is reduced as a result. The performances of the Poisson noise reduction are demonstrated in some experiments of the image reconstruction of time-domain DOT. In simulations, the proposed method reduces the relative error between the noise-free and noisy data to about one thirtieth, and the reconstructed DOT image was smoothed by the proposed noise reduction. The variance of the reconstructed absorption coefficients decreased by 22% in a phantom experiment. The quality of DOT, which can be applied to breast cancer screening etc., is improved by the proposed noise reduction.
    研究論文(学術雑誌), 英語
  • Reduction of image artifacts induced by change in the optode coupling in time-resolved diffuse optical tomography
    Ryo Fukuzawa; Shinpei Okawa; Shoko Matsuhashi; Takashi Kusaka; Yukari Tanikawa; Yoko Hoshi; Feng Gao; Yukio Yamada
    JOURNAL OF BIOMEDICAL OPTICS, SPIE-SOC PHOTO-OPTICAL INSTRUMENTATION ENGINEERS, 16巻, 11号, 掲載ページ Paper No. 116022 (116022-1 , 出版日 2011年11月, 査読付, Tomographic images of the optical properties can be reconstructed using inversion algorithms for diffuse optical tomography (DOT); however, changes in the optode coupling that occurs while obtaining an object's measurements may often lead to the presence of artifacts in the reconstructed images. To reduce the number of artifacts induced by optode coupling, previous studies have introduced (unknown) coupling coefficients in reconstruction algorithms, which were found to be effective for continuous wave-and frequency-domain DOT. This study aims to investigate the effects of optode calibration on the reconstructed images of time-domain DOT. Here, coupling coefficients are incorporated into the time-domain DOT algorithm based on a modified generalized pulse spectrum technique. The images of the absorption coefficient are reconstructed in various numerical simulations, phantom experiments, and in vivo experiments of time-domain DOT. As a result, the artifacts resulting from changes in optode coupling are reduced in the reconstructed images of the absorption coefficient, thereby demonstrating that introduction of coupling coefficients is effective in time-domain DOT. Moreover, numerical simulations, phantom experiments, and in vivo studies have validated this algorithm. (C) 2011 Society of Photo-Optical Instrumentation Engineers (SPIE). [DOI: 10.1117/1.3653236]
    研究論文(学術雑誌), 英語
  • Dermal carbonyl modification is related to the yellowish color change of photo-aged Japanese facial skin
    Yuki Ogura; Tomohiro Kuwahara; Minoru Akiyama; Shingo Tajima; Kazuhisa Hattori; Kouhei Okamoto; Shinpei Okawa; Yukio Yamada; Hchiro Tagami; Motoji Takahashi; Tetsuji Hirao
    Journal of Dermatological Science, Vol. 64巻, 掲載ページ pp. 45-52, 出版日 2011年09月, 査読付
    研究論文(学術雑誌), 英語
  • Temperature imaging of water in a microchannel using thermal sensitivity of near-infrared absorption
    Naoto Kakuta; Yuko Fukuhara; Katsuya Kondo; Hidenobu Arimoto; Yukio Yamada
    Lab on a Chip, 11巻, 掲載ページ 3479-3486, 出版日 2011年09月, 査読付
    研究論文(学術雑誌), 英語
  • 3D analysis of intracortical microvasculature during chronic hypoxia in mouse brain
    Kouichi Yoshihara; Hiroyuki Takuwa; Iwao Kanno; Shinpei Okawa; Yukio Yamada; Kazuto Masamoto
    ISOTT 2011, ISOTT 2011巻, 掲載ページ 1-8, 出版日 2011年07月, 査読付
    研究論文(国際会議プロシーディングス), 英語
  • Time-domain fluorescence diffuse optical tomography for living animals by total-light algorithm
    Goro Nishimura; Kamlesh Awasthi; Kitsakorn Locharoenrat; Shinpei Okawa; Yukio Yamada
    Progress in Biomedical Optics and Imaging - Proceedings of SPIE, 7896巻, 出版日 2011年, 査読付, We are reporting the first trial image reconstruction of a implanted fluorescent target into a live rat abdomen. We use a simplified algorithm for fluorescence diffuse optical tomography (FDOT), so-called the Total-light algorithm to obtain the absorption image of the target from the measured mean-transit time (MTT). We reconstructed two absorption images with and without a fluorescence target. It is difficult to identify something in the absorption images. However, the difference image between the two images highlights the target. This suggests that our algorithm is robust to the artifacts in the images in the real situation of in vivo measurements. © 2011 SPIE.
    研究論文(国際会議プロシーディングス), 英語
  • Time-domain fluorescence diffuse optical tomography for living animals by total-light algorithm
    Goro Nishimura; Kamlesh Awasthi; Kitsakorn Locharoenrat; Shinpei Okawa; Yukio Yamada
    OPTICAL TOMOGRAPHY AND SPECTROSCOPY OF TISSUE IX, SPIE-INT SOC OPTICAL ENGINEERING, 7896巻, 掲載ページ 78962Q-1-78962Q-7, 出版日 2011年, 査読付, We are reporting the first trial image reconstruction of a implanted fluorescent target into a live rat abdomen. We use a simplified algorithm for fluorescence diffuse optical tomography (FDOT), so-called the Total-light algorithm to obtain the absorption image of the target from the measured mean-transit time (MTT). We reconstructed two absorption images with and without a fluorescence target. It is difficult to identify something in the absorption images. However, the difference image between the two images highlights the target. This suggests that our algorithm is robust to the artifacts in the images in the real situation of in vivo measurements.
    研究論文(国際会議プロシーディングス), 英語
  • MEASUREMENT OF FLUORESCENCE PROPERTIES IN LIGHT SCATTERING MEDIUM
    Shoji Maruoka; Yohei Mitsui; Shinpei Okawa; Yoko Hoshi; Yukio Yamada
    PROCEEDINGS OF THE ASME/JSME 8TH THERMAL ENGINEERING JOINT CONFERENCE 2011, VOL 1 PTS A AND B, AMER SOC MECHANICAL ENGINEERS, 掲載ページ 33-+, 出版日 2011年, 査読付, The purpose of this study is to measure the fluorescence properties of Indocyaninegreen (ICG) which is a fluorescence dye to be used as a fluorescence probe for the use of fluorescence imaging in biomedical applications. The fluorescence molecular imaging is expected to solve the issues in preclinical studies which require a lot of time, labors and sacrificed animals. Information of living body can be obtained by measuring the fluorescent properties of the probe in biological media. The absorption and emission spectra and the lifetime of ICG in non-scattering and scattering media were measured in this study ICG was dissolved in water, in plasma, in Intralipid and in a mixture of plasma and Intralipid to simulate the environment in living tissues. The absorption and emission spectra were measured using a fluorescence spectrophotometer. The fluorescence lifetimes were measured using a time-resolved measurement method Results suggest that the fluorescent properties are affected by the reaction between ICG and biological tissues.
    研究論文(国際会議プロシーディングス), 英語
  • TIME-RESOLVED DIFFUSE OPTICAL TOMOGRAPHY OF HUMAN FOREARM UNDER EXERCISE
    Yasuomi Endo; Yukari Tanikawa; Shinpei Okawa; Kazuto Masamoto; Hidetaka Okada; Tomohiro Kizuka; Michio Miyakawa; Yoko Hoshi; Yukio Yamada
    PROCEEDINGS OF THE ASME/JSME 8TH THERMAL ENGINEERING JOINT CONFERENCE 2011, VOL 1 PTS A AND B, AMER SOC MECHANICAL ENGINEERS, Paper No. AJTEC2011-44486巻, 掲載ページ 71-+, 出版日 2011年, 査読付, Light in the near-infrared wavelength range can penetrate deeping into biological tissues because the absorption by both water and hemoglobin is much smaller than in the other wavelength ranges. Oxygenated and deoxygenated hemoglobins have different light absorption characteristics. Therefore, by obtaining tomographic images of the absorption characteristics, it will be possible to know the hemodynamics inside deep tissues. Thus, the diffuse optical tomography (DOT) is expected as a new modality of biomedical imaging. In this study, we try to obtain DOT images of the forearms by conducting two types of exercise, and their differences caused by the muscle activity are discussed. By comparing the reconstructed DOT images with the magnetic resonance images of the forearm at the same position, the activated muscles can be identified in detail. As a result, the hemodynamics in the dominant muscles when performing flexion and extension of wrist are observed.
    研究論文(国際会議プロシーディングス), 英語
  • INFLUENCE OF BLOOD GLUCOSE LEVEL ON THE SCATTERING COEFFICIENT OF THE SKIN IN NEAR-INFRARED SPECTROSCOPY
    Sachiko Kessoku; Katsuhiko Maruo; Shinpei Okawa; Kazuto Masamoto; Yukio Yamada
    PROCEEDINGS OF THE ASME/JSME 8TH THERMAL ENGINEERING JOINT CONFERENCE 2011, VOL 1 PTS A AND B, AMER SOC MECHANICAL ENGINEERS, Paper No. AJTEC2011-44471巻, 掲載ページ 47-+, 出版日 2011年, 査読付, Various non-invasive glucose monitoring methods using near-infrared spectroscopy have been investigated although no method has been successful so far Our previous study has proposed a new promising method utilizing numerically generated absorbance spectra instead of the experimentally acquired absorbance spectra. The method suggests that the correct estimation of the optical properties is very important for numerically generating the absorbance spectra. The purpose of this study is to measure the change in the optical properties of the skin with the change in the blood glucose level in vivo. By measuring the reflectances of light incident on the skin surface at two distances from the incident point, the optical properties of the skin can be estimated. The estimation is a kind of the inverse problem based on the simulation of light propagation in the skin. Phantom experiments have verified the method and in vivo experiments are to be performed
    研究論文(国際会議プロシーディングス), 英語
  • EFFECT OF THE ARRANGEMENT OF OPTODES FOR 3D DIFFUSE OPTICAL TOMOGRAPHY
    Kazuhiro Uchida; Shinpei Okawa; Kazuto Masamoto; Yoko Hoshi; Yukio Yamada
    PROCEEDINGS OF THE ASME/JSME 8TH THERMAL ENGINEERING JOINT CONFERENCE 2011, VOL 1 PTS A AND B, AMER SOC MECHANICAL ENGINEERS, Paper No. AJTEC2011-44480巻, 掲載ページ 65-+, 出版日 2011年, 査読付, Diffuse optical tomography (DOT) can obtain tomographic images of hemodynamics such as the oxygenation state and blood volume in tissues using light in the near infrared wavelength range where tissues absorb light weakly and oxy- and deoxy-hemoglobins show different absorbing characteristics. For 3D-DOT, much more optodes than those for 2D-DOT are desirable for high quality images. But practically the number of the optodes is limited and it is necessary to find the optimum arrangement of the optodes. This paper studies the effect of the optode arrangement on the reconstructed images by simulation of 3D-DOT when the number of the optodes is 16 and the object is a sphere with a diameter of 100 mm. Simulation results show that the optode arrangement which can effectively detect the light propagating through the target is important to reconstruct the target at the correct positions.
    研究論文(国際会議プロシーディングス), 英語
  • MEASUREMENT OF OPTICAL PROPERTIES OF HUMAN SKIN
    Kazuhisa Hattori; Tomohiro Kuwahara; Masato Ohmi; Masamitsu Haruna; Shinpei Okawa; Kazuto Masamoto; Yukio Yamada
    PROCEEDINGS OF THE ASME/JSME 8TH THERMAL ENGINEERING JOINT CONFERENCE 2011, VOL 1 PTS A AND B, AMER SOC MECHANICAL ENGINEERS, Paper No. AJTEC2011-44475巻, 掲載ページ 55-63, 出版日 2011年, 査読付, In order to predict the skin colors, we need to analyze the reflection spectra of the skins. For the diffuse reflection, it is essential to know the skin optical properties that describe the propagation of light in the skin. We measure the absorption coefficient mu(a), scattering coefficient mu(s), scattering phase function p(theta) and refractive index n of human skins in this study. We attempt to build a measurement system which can accurately measure the optical properties of the skin samples with a size of as small as 5 mm and a thickness of as thin as 50 micrometer in the visible wavelength range with the wavelength step of 50 nm. Then we measured the optical properties of stratum corneum obtained from a cultured model of human epidermis and those of epidermis obtained from human skin. The effect of the exposure of epidermis to sunlight on the optical properties is discussed.
    研究論文(国際会議プロシーディングス), 英語
  • Development of image reconstruction algorithms for fluorescence diffuse optical tomography using total light approach
    S. Okawa; H. Yamamoto; Y. Miwa; Y. Yamada
    DIFFUSE OPTICAL IMAGING III, SPIE-INT SOC OPTICAL ENGINEERING, 8088巻, 掲載ページ 1-6, 出版日 2011年, 査読付, Fluorescence diffuse optical tomography (FDOT) based on the total light approach is developed. The continuous wave light is used for excitation in this system. The reconstruction algorithm is based on the total light approach that reconstructs the absorption coefficients increased by the fluorophore. Additionally we propose noise reduction using the algebraic reconstruction technique (ART) incorporating the truncated singular value decomposition (TSVD). Numerical and phantom experiments show that the developed system successfully reconstructs the fluorophore concentration in the biological media, and the ART with TSVD alleviates the influence of noises. In vivo experiment demonstrated that the developed FDOT system localized the fluorescent agent which was concentrated in the cancer transplanted into a kidney in a mouse.
    研究論文(国際会議プロシーディングス), 英語
  • Improvement of image quality of time-domain diffuse optical tomography with l<inf>p</inf> sparsity regularization
    Shinpei Okawa; Yoko Hoshi; Yukio Yamada
    Biomedical Optics Express, OSA - The Optical Society, 2巻, 12号, 掲載ページ 3334-3348, 出版日 2011年, 査読付, An l<
    inf>
    p<
    /inf>
    (0 <
    p ≤ 1) sparsity regularization is applied to time-domain diffuse optical tomography with a gradient-based nonlinear optimization scheme to improve the spatial resolution and the robustness to noise. The expression of the l<
    inf>
    p<
    /inf>
    sparsity regularization is reformulated as a differentiable function of a parameter to avoid the difficulty in calculating its gradient in the optimization process. The regularization parameter is selected by the L-curve method. Numerical experiments show that the l<
    inf>
    p<
    /inf>
    sparsity regularization improves the spatial resolution and recovers the difference in the absorption coefficients between two targets, although a target with a small absorption coefficient may disappear due to the strong effect of the l<
    inf>
    p<
    /inf>
    sparsity regularization when the value of p is too small. The l<
    inf>
    p<
    /inf>
    sparsity regularization with small p values strongly localizes the target, and the reconstructed region of the target becomes smaller as the value of p decreases. A phantom experiment validates the numerical simulations. © 2011 Optical Society of America.
    研究論文(学術雑誌), 英語
  • Reconstruction of fluorescence/bioluminescence sources in biological medium with spatial filter
    Shinpei Okawa; Yukio Yamada
    Optics Express, 18巻, 12号, 掲載ページ 13151-13172, 出版日 2010年12月, 査読付
    研究論文(学術雑誌), 英語
  • Effective optode configuration for the image reconstruction in diffuse optical tomography
    Kazuhiro Uchida; Shinpei Okawa; Shoko Matsuhashi; Yoko Hoshi; Yukio Yamada
    Medical Laser Application, 25巻, 3号, 掲載ページ 154-160, 出版日 2010年08月, 査読付, The influence of the configuration of the optodes on the images of diffuse optical tomography (DOT) was investigated using 3D numerical simulations. 3D distributions of the absorption coefficients in a spherical object were reconstructed from the numerically simulated measurement data for various configurations of the optodes. When the optodes were placed in a plane containing a target which strongly absorbs light, the target could be reconstructed with good localization. For good reconstruction of the target, it was found to be very important that the optode configuration was optimized in order to detect light propagating through the target effectively. The simulations also showed that the optode configuration affects the quality of the reconstructed images and that some prior information about the measured object improved the DOT images. Finally the simulation results were verified by a phantom experiment. © 2010 Elsevier GmbH.
    研究論文(学術雑誌), ドイツ語
  • Reduction of Poisson Noise for Time-Resolved Diffuse Optical Measurement
    S. Okawa; Y. Yamada
    Proc. of SICE Annual Conference 2010 in Taiwan, 1巻, 掲載ページ 1, 出版日 2010年08月, 査読付
    研究論文(国際会議プロシーディングス), 英語
  • Source Reconstruction with Spatial Filter and Reduction of Artifacts in Fluorescence/Bioluminescence Diffuse Optical Tomography
    S. Okawa; Y. Yamada
    Proc. of SICE Annual Conference 2010 in Taiwan, 1巻, 掲載ページ 2, 出版日 2010年08月, 査読付
    研究論文(国際会議プロシーディングス), 英語
  • Reconstruction of fluorescence/bioluminescence sources in biological medium with spatial filter
    Shinpei Okawa; Yukio Yamada
    Optics Express, 18巻, 12号, 掲載ページ 13151-13172, 出版日 2010年07月, 査読付
    研究論文(学術雑誌), 英語
  • Quantification of Fluorescence Target in Tissue Phantoms by Time‐Domain Diffuse Optical Tomography with Phantoms—Total‐Light Approach
    Goro Nishimura; Kamlesh Awasthi; Kitsakorn Locharoenrat; Shinpei Okawa; Yukio Yamada
    OSA Topical Meeting, Biomedical Optics (BIOMED), Abstract Book, 掲載ページ BTuD11, 出版日 2010年04月, 査読付
    研究論文(国際会議プロシーディングス), 英語
  • Simultaneous fluorescence yield and lifetime tomography from time-resolved transmittances of small-animal-sized phantom
    Feng Gao; Jiao Li; Limin Zhang; Patrick Poulet; Huijuan Zhao; Yukio Yamada
    Applied Optics, 49巻, 16号, 掲載ページ 3163-3172, 出版日 2010年04月, 査読付
    研究論文(学術雑誌), 英語
  • Removal of a hydrogenated amorphous carbon film from the tip of a micropipette electrode using direct current corona discharge
    Naoto Kakuta; Naoki Okuyama; Yukio Yamada
    REVIEW OF SCIENTIFIC INSTRUMENTS, AMER INST PHYSICS, 81巻, 2号, 掲載ページ 1-6, 出版日 2010年02月, 査読付, Micropipette electrodes are fabricated by coating glass micropipettes first with metal and then with hydrogenated amorphous carbon (a-C:H) as an electrical insulator. Furthermore, at the tip of the micropipette electrode, the deposited a-C:H film needs to be removed to expose the metal-coated surface and hollow for the purposes of electrical measurement and injection. This paper describes a convenient and reliable method for removing the a-C:H film using direct current corona discharge in atmospheric air. The initial film removal occurred at an applied voltage of 1.5-2.0 kV, accompanied by an abrupt increase in the discharge current. The discharge current then became stable at a microampere level in the glow corona mode, and the removed area gradually extended.
    研究論文(学術雑誌), 英語
  • Effects of spatial variation of skull and cerebrospinal fluid layers on optical mapping of brain activities
    Shuping Wang; Nanae Shibahara; Daishi Kuramashi; Shinpei Okawa; Naoto Kakuta; Eiji Okada; Atsushi Maki; Yukio Yamada
    Optical Review, 17巻, 4号, 掲載ページ 410-420, 出版日 2010年, 査読付, In order to investigate the effects of anatomical variation in human heads on the optical mapping of brain activity, we perform simulations of optical mapping by solving the photon diffusion equation for layered-models simulating human heads using the finite element method (FEM). Particularly, the effects of the spatial variations in the thicknesses of the skull and cerebrospinal fluid (CSF) layers on mapping images are investigated. Mapping images of single active regions in the gray matter layer are affected by the spatial variations in the skull and CSF layer thicknesses, although the effects are smaller than those of the positions of the active region relative to the data points. The increase in the skull thickness decreases the sensitivity of the images to active regions, while the increase in the CSF layer thickness increases the sensitivity in general. The images of multiple active regions are also influenced by their positions relative to the data points and by their depths from the skin surface. © 2010 The Optical Society of Japan.
    研究論文(学術雑誌), 英語
  • Estimation of the absorption coefficients of two-layered media by a simple method using spatially and time-resolved reflectances
    M. Shimada; C. Sato; Y. Hoshi; Y. Yamada
    PHYSICS IN MEDICINE AND BIOLOGY, IOP PUBLISHING LTD, 54巻, 16号, 掲載ページ 5057-5071, 出版日 2009年08月, 査読付, Our newly developed method using spatially and time-resolved reflectances can easily estimate the absorption coefficients of each layer in a two-layered medium if the thickness of the upper layer and the reduced scattering coefficients of the two layers are known a priori. We experimentally validated this method using phantoms and examined its possibility of estimating the absorption coefficients of the tissues in human heads. In the case of a homogeneous plastic phantom (polyacetal block), the absorption coefficient estimated by our method agreed well with that obtained by a conventional method. Also, in the case of two-layered phantoms, our method successfully estimated the absorption coefficients of the two layers. Furthermore, the absorption coefficients of the extracerebral and cerebral tissue inside human foreheads were estimated under the assumption that the human heads were two-layered media. It was found that the absorption coefficients of the cerebral tissues were larger than those of the extracerebral tissues.
    研究論文(学術雑誌), 英語
  • Temperature Imaging of Sub-Millimeter-Thick Water Using a Near-Infrared Camera
    Naoto Kakuta; Katsuya Kondo; Atsushi Ozaki; Hidenobu Arimoto; Yukio Yamada
    International Journal of Heat and Mass Transfer, 52巻, 掲載ページ 4221-4228, 出版日 2009年07月, 査読付
    研究論文(学術雑誌), 英語
  • Effects of Spatial Variation of Skull and Cerebrospinal Fluid Layers on Optical Mapping of Brain Activities
    Shuping Wang; N. Shibahara; D. Kuramashi; S. Okawa; N. Kakuta; E. Okada; A. Maki; Y. Yamada
    Proceedings of APBP2009, 掲載ページ 114-115, 出版日 2009年05月, 査読付
    研究論文(国際会議プロシーディングス), 英語
  • Time-resolved DOT images of human forearm under excise
    Y. Tanikawa; Feng Gao; M. Miyakawa; T. Kiryu; Y. Endo; S. Okawa; Y. Yamada
    Proceedings of APBP2009, 掲載ページ 120-121, 出版日 2009年05月, 査読付
    研究論文(国際会議プロシーディングス), 英語
  • Effects of the anatomy of the head on optical mapping of brain activities
    M. Oki; N. Shibahara; R. Togashi; S. Okawa; Y. Hoshi; Y. Yamada
    Proceedings of APBP2009, 掲載ページ 129-130, 出版日 2009年05月, 査読付
    研究論文(国際会議プロシーディングス), 英語
  • Reduction of Poisson Noise from Time-Resolved Data for Diffuse Optical Tomography
    S. Okawa; Y. Yamada
    Proceedings of APBP2009, 掲載ページ 131-132, 出版日 2009年05月, 査読付
    研究論文(国際会議プロシーディングス), 英語
  • Phantom experiments of fluorescence diffuse optical tomography
    A. Yano; A. Marjono; K. Uchida; T. Abe; S. Okawa; G. Nishimura; Y. Hoshi; F. Gao; Y. Yamada
    Proceedings of APBP2009, 掲載ページ 137-138, 出版日 2009年05月
    研究論文(国際会議プロシーディングス), 英語
  • Effects of the movement of probes on the images of diffuse optical tomography
    S. Matsuhashi; R. Fukuzawa; S. Okawa; Y. Hoshi; Y. Yamada
    Proceedings of APBP2009, 掲載ページ 139-140, 出版日 2009年05月, 査読付
    研究論文(国際会議プロシーディングス), 英語
  • Simultaneously reconstructing fluorescent yield and lifetime from time-resolved transmittances of a small-animal-sized phantom
    Feng Gao; Limin Zhang; Patrick Poulet; Jiao Li; Huijuan Zhao; Yukio Yamada
    Progress in Biomedical Optics and Imaging - Proceedings of SPIE, 7369巻, 出版日 2009年, 査読付, A full three-dimensional, featured-data algorithm for time-domain diffuse fluorescence tomography is presented, which inverts the Laplace-transformed time-domain coupled diffusion equations and employs a pair of real-domain transform-factors to effectively separate the fluorescent yield and lifetime parameters. By use of a multi-channel time-correlation single photon counting system and a normalized Born formulation for the inversion, the proposed scheme is experimentally validated to achieve simultaneous reconstruction of the fluorescent yield and lifetime distributions with a reasonable accuracy. © 2009 SPIE-OSA.
    研究論文(国際会議プロシーディングス), 英語
  • 3D light source reconstruction with spatial filter for fluorescence/ bioluminescence diffuse optical tomography
    Shinpei Okawa; Yukio Yamada
    Progress in Biomedical Optics and Imaging - Proceedings of SPIE, 7369巻, 掲載ページ Article No. 736916, 出版日 2009年, 査読付, A 3D reconstruction of light sources in biological medium with spatial filtering and updating of the forward model is simulated numerically with use of the optical properties of mouse. The spatial filters locate the strong sources in the medium. The estimated source strength is used to remove the source positions which are not contributed to the measurement data, and improved the spatial resolution of spatial filtering. The forward model updated by spatial filtering is useful to reduce the noises by using singular value decomposition. By removing the noise space from the measurement data, the noises are reduced. The numerical simulations with a numerical phantom with the optical properties of mouse showed that the proposed method succeeded in localizing the sources in a 3D medium and that the additional noise reduction improved the reconstructed images. The proposed reconstruction scheme including the noise reduction achieves robust reconstruction of the light source distribution from the noisy measurement data and incorrect information of the optical properties of the measured subject. © 2009 SPIE-OSA.
    研究論文(国際会議プロシーディングス), 英語
  • 近赤外光を用いた非接触型微量流量計の研究
    山下健作; 久保田壮一; 桃木秀幸; 角田直人; 大川晋平; 有本英伸; 落合洋; 山田幸生
    日本機械学会論文集(B編), 一般社団法人日本機械学会, 74巻, 746号, 掲載ページ 2198-2204, 出版日 2008年10月, 査読付, We have proposed a novel method of non-contact thermal type measurement for low flow rates using radiation heating and spectroscopy of water in the near-infrared wavelength range. We made a simulation for studying the performance of the flowmeter, and based on the simulation we conducted experiments using a prototype flowmeter. We obtained calibration curves between the estimated and true flow rates. From the experimental results, we can measure the flow rates from 0.3 to 9ml/min with the accuracy of about 10% of the flow rate. We also obtained agreement between the simulation and measurement results. Discussions are made to improve the measurement accuracy.
    研究論文(学術雑誌), 日本語
  • Total light approach of time-domain fluorescence diffuse optical tomography
    Andhi Marjono; Akira Yano; Shinpei Okawa; Feng Gao; Yukio Yamada
    OPTICS EXPRESS, OPTICAL SOC AMER, 16巻, 19号, 掲載ページ 15268-15285, 出版日 2008年09月, 査読付, In this study, time-domain fluorescence diffuse optical tomography in biological tissue is numerically investigated using a total light approach. Total light is a summation of excitation light and zero-lifetime emission light divided by quantum yield. The zero-lifetime emission light is an emitted fluorescence light calculated by assuming that the fluorescence lifetime is zero. The zero-lifetime emission light is calculated by deconvolving the actually measured emission light with a lifetime function, an exponential function for fluorescence decay. The object for numerical simulation is a 2-D 10 mm-radius circle with the optical properties simulating biological tissues for near infrared light, and contains regions with fluorophore. The inverse problem of fluorescence diffuse optical tomography is solved using time-resolved simulated measurement data of the excitation and total lights for reconstructing the absorption coefficient and fluorophore concentration simultaneously. The mean time of flight is used as the featured data-type extracted from the time-resolved data. The reconstructed images of fluorophore concentration show good quantitativeness and spatial reproducibility. By use of the total light approach, computation is performed much faster than the conventional ones. (C) 2008 Optical Society of America.
    研究論文(学術雑誌), 英語
  • Optical brain imaging in infants by use of near-infrared diffuse optical tomography
    T. Kusaka; S. Okawa; M. Ueno; R. Fukuzawa; T. Nishida; K. Isobe; Y. Tanikawa; F. Gao; C. Sato; Y. Hoshi; Y. Yamada
    Abstract Book of The 36th Annual Conference of International Society of Oxygen Transport to Tissue (ISOTT2008), 掲載ページ 18, 出版日 2008年08月
    研究論文(国際会議プロシーディングス), 英語
  • A self-normalized, full time-resolved method for fluorescence diffuse optical tomography
    Feng Gao; Huijuan Zhao; Limin Zhang; Yukari Tanikawa; Andhi Marjono; Yukio Yamada
    Optics Express, 16巻, 17号, 掲載ページ 13104-13121, 出版日 2008年07月, 査読付
    研究論文(学術雑誌), 英語
  • Temperature measurements of turbid aqueous solutions using near-infrared spectroscopy
    Naoto Kakuta; Hidenobu Arimoto; Hideyuki Momoki; Fuguo Li; Yukio Yamada
    Applied Optics, Vol. 47, Issue 13, pp. 2227-2233 (2008), 47巻, 13号, 掲載ページ 2227-2233, 出版日 2008年04月
    研究論文(学術雑誌), 英語
  • Source estimation with spatial filter for fluorescence diffuse optical tomography
    Shinpei Okawa; Yukio Yamada
    2008 Biomedical Optics Topical Meeting, 掲載ページ Poster No. BSuE41, 出版日 2008年03月, 査読付
    研究論文(国際会議プロシーディングス), 英語
  • Full Time-Resolved Fluorescence Diffuse Optical Tomography using Total Light Approach
    Andhi Marjono; Akira Yano; Shinpei Okawa; Yukio Yamada
    2008 Biomedical Optics Topical Meeting, 掲載ページ Poster No. BMD33, 出版日 2008年03月, 査読付
    研究論文(国際会議プロシーディングス), 英語
  • Quantitative Imaging of Platelet Aggregation in a Microchannel Using an Interfacial Collision Reactor
    Taisuke Hirono; Shinpei Okawa; Yukio Yamada
    2008 Biomedical Optics Topical Meeting, 掲載ページ Poster No. BTuF31, 出版日 2008年03月, 査読付
    研究論文(国際会議プロシーディングス), 英語
  • 化学反応速度論的数理モデルを用いた血小板凝集の定量化
    廣野泰亮; 大川晋平; 山田幸生
    生体医工学, 46巻, 2号, 掲載ページ 177-188, 出版日 2008年02月, 査読付
    研究論文(学術雑誌), 日本語
  • Time‐Domain Fluorescence Molecular Tomography Based on Generalized Pulse Spectrum Technique
    Feng Gao; Wei Liu; Huijuan Zhao; Yukari Tanikawa; Andhi Marjono; Yukio Yamada
    2006 Biomedical Optics Topical Meeting, SPIE-INT SOC OPTICAL ENGINEERING, 6826巻, 掲載ページ U489-U496, 出版日 2008年, 査読付, A linear generalized pulse spectrum technique for image reconstruction of fluorescence molecular tomography is proposed. The algorithm employs a finite element method solution to the Laplace-transformed coupled diffusion equations and can simultaneously reconstruct both fluorescent yield and lifetime images of fluorophores. The proposed algorithm was validated using simulated data for 3D phantoms. We investigated the ability of the algorithm to reconstruct the fluorescent yield and lifetime at different region, contrasted the imaging quality of different target lifetime and proved the noise-robustness by using noisy data with different signal-to-noise ratio. The results show that the approach accurately retrieves the position and shape of the target and prove the effectiveness of the methodology.
    研究論文(国際会議プロシーディングス), 英語
  • Microfluidic image cytometry for measuring number and sizes of biological cells flowing through a microchannel using the micro-PIV technique
    T. Hirono; H. Arimoto; S. Okawa; Y. Yamada
    Measurement Science and Technology, Institute of Physics Publishing, 19巻, 2号, 掲載ページ No. 025401 (13pp), 出版日 2008年, 査読付, Microfluidic image cytometry is developed and validated both theoretically and experimentally, which is a method for the simultaneous measurement of the number and sizes of particles flowing through a microchannel using image sequence analysis and micro particle image velocimetry technique. Theoretical considerations on image formation in this method predict the image profile of a known particle and suggest that corrections are required in particle size measurement in order to cancel the effects of both diffraction and out-of-focus location. A dilution series of 2 μm polystyrene particle suspensions were measured and compared with the results obtained by conventional Bürker-Türk hemocytometry for validation of the particle counting. For the particle diameter measurements, the diameters of 2, 5, 10 and 20 μm particles were measured and compared with the official values of the manufacturer. The results of the number and sizes of the particles measured by the proposed method agreed well with the reference values. We hope that the proposed method will be applicable to the quantitative study of platelet aggregation in blood flow and become a powerful diagnostic tool in the future. © 2008 IOP Publishing Ltd.
    研究論文(学術雑誌), 英語
  • Diffuse optical tomography maximizing localized variation in optical properties
    Shinpei Okawa; Yukio Yamada
    2008 PROCEEDINGS OF SICE ANNUAL CONFERENCE, VOLS 1-7, IEEE, 掲載ページ 1035-1038, 出版日 2008年, 査読付, A new regularization method is introduced to the inverse problem in Diffuse Optical Tomography to improve the localization of the reconstructed abnormal optical properties. The regularization term is designed to minimize the regions and to maximize the peak value of the optical properties. Numerical simulations show the proposed method successfully reconstructs the localized abnormal region. The selection and the effects of the regularization parameters are discussed through some numerical simulations. The proposed method can be effective for screening of the breast cancer in the early stages.
    研究論文(国際会議プロシーディングス), 英語
  • Time-resolved diffuse optical tomography and its application to in vitro and in vivo imaging
    H. Zhao; F. Gao; Y. Tanikawa; Y. Yamada
    J. Biomedical Optics, 12巻, 6号, 掲載ページ No. 062107(CID)-62107, 出版日 2007年12月, 査読付
    研究論文(学術雑誌), 英語
  • Full Time-Resolved Data Scheme Using Total Light Approach in Time-Domain Fluorescence Diffuse Optical Tomography
    A. Marjono; A. Yano; S. Okawa; F. Gao; Y. Yamada
    Proceedings of 3rd Asian and Pacific Rim Symposium on Biophotonics, 掲載ページ 47-48, 出版日 2007年07月, 査読付
    研究論文(国際会議プロシーディングス), 英語
  • Microfluidic Image Cytometry for Measuring of Number and Sizes of Biological Particles
    T. Hirono; S. Okawa; H. Arimoto; Y. Yamada
    Proc. of 3rd Asian and Pacific Rim Symposium on Biophotonics, 掲載ページ 65-66, 出版日 2007年07月, 査読付
    研究論文(国際会議プロシーディングス), 英語
  • In vivo measurement of premature neonate head using diffuse optical tomography
    M. Ueno; R. Fukuzawa; S. Okawa; Y. Yamada; T. Kusaka; T. Nishida; K. Isobe; Y. Tanikawa; F. Gao; C. Sato; Y. Hoshi
    Proc. of 3rd Asian and Pacific Rim Symposium on Biophotonics, 掲載ページ 43-44, 出版日 2007年07月, 査読付
    研究論文(国際会議プロシーディングス), 英語
  • Effects of the CSF Layer on the Optical Mapping of Brain Activity
    N. Shibahara; S. Okawa; Y. Yamada
    Proc. of 3rd Asian and Pacific Rim Symposium on Biophotonics, 掲載ページ 95-96, 出版日 2007年07月, 査読付
    研究論文(国際会議プロシーディングス), 英語
  • Light propagation for time-domain fluorescence diffuse optical tomography by convolution using lifetime function
    Andhi Marjono; Shinpei Okawa; Feng Gao; Yukio Yamada
    OPTICAL REVIEW, OPTICAL SOC JAPAN, 14巻, 3号, 掲載ページ 131-138, 出版日 2007年05月, 査読付, Time-domain light propagation in biological tissue is studied by solving the forward problem for fluorescence diffuse optical tomography using a convolution of the zero-lifetime emission light and the exponential function for a finite lifetime. We firstly formulate the fundamental equations in a time-domain assuming that the fluorescence lifetime is equal to zero, and then the solution including the lifetime is obtained by convolving the emission light and the lifetime function. The model is a two-dimensional (2-D) 10 mm-radius circle with the optical properties simulating biological tissue for the near infrared light, and contains some inclusions with fluorophores. Temporal and spatial profiles of excitation and emission light are calculated and discussed for several models with different inclusions. The results are physically reasonable and will be used for the inverse problem of fluorescence diffuse optical tomography. (c) 2007 The Optical Society of Japan
    研究論文(学術雑誌), 英語
  • 341 拡散光トモグラフィ装置を用いた未熟児頭部のin vivo測定(GS-6:一般セッション:医療・生体計測,オーガナイズドセッション1:生物流体とバイオミメティクス)
    上野 雅範; 佐藤 知絵; 星 詳子; 福沢 遼; 大川 晋平; 山田 幸生; 日下 隆; 西田 智子; 磯部 健一; 谷川 ゆかり; 高 峰
    バイオエンジニアリング講演会講演論文集, 一般社団法人 日本機械学会, 2006巻, 0号, 掲載ページ 338-339, 出版日 2007年, 査読付
    日本語
  • Full time-resolved scheme data in time-domain fluorescence diffuse optical tomography
    Andhi Marjono; Akira Yano; Shinpei Okawa; Feng Gao; Yukio Yamada
    OPTICAL TOMOGRAPHY AND SPECTROSCOPY OF TISSUE VII, SPIE-INT SOC OPTICAL ENGINEERING, 6434巻, 出版日 2007年, 査読付, In this study, time-domain fluorescence diffuse optical tomography (FDOT) in biological tissue is investigated by solving the inverse problem using a convolution and deconvolution of the zero-lifetime emission light intensity and the exponential function for a finite lifetime, respectively. We firstly formulate the fundamental equations in time-domain assuming that the fluorescence lifetime is equal to zero, and then the solution including the lifetime is obtained by convolving the emission light intensity and the lifetime function. The model is a 2-D 10 mm-radius circle with the optical properties simulating biological tissue for the near infrared light, and contains some regions with fluorophores. Temporal and spatial profiles of excitation and emission light intensities are calculated and discussed for several models. The inverse problem of fluorescence diffuse optical tomography is solved using simulated measurement emission intensities for reconstructing fluorophore concentration. A time-domain measurement system uses ultra-short pulsed laser for excitation and measures the temporal and spatial distributions of fluorescence emitting from the tissue surface. To improve image quality, we propose implementation of a FDOT algorithm using full time-resolved (TR) data.
    研究論文(国際会議プロシーディングス), 英語
  • Measurement of temperature differences between micro-regions in water using near-infrared spectroscopy
    Naoto Kakuta; Atsushi Ozaki; Fuguo Li; Hidenobu Arimoto; Yukio Yamada
    Annual International Conference of the IEEE Engineering in Medicine and Biology - Proceedings, 掲載ページ 4564-4567, 出版日 2007年, 査読付, We have developed a method for measuring the temperature of micro-regions in aqueous solutions using near-infrared spectroscopy that enables us to measure the temperature of biological cells, tissues, and biochemical solutions in vitro. The measurement principle is based on the fact that the peak wavelength of the water absorption band with its center near 1450 nm shifts with changes in temperature. The measurement system, which consists of a biological microscope and two spectrophotometers, can measure respective absorbance spectra for two areas that are each 80 μm in diameter. We formed the temperature distribution in a 500-μm thick water film by heating an immersed Nichrome wire and measured the temperature difference between the two areas. The results of the measurement were compared to a calculated temperature distribution. © 2007 IEEE.
    研究論文(国際会議プロシーディングス), 英語
  • A linear GPST-based scheme for time-domain fluorescence molecular tomography
    Feng Gao; Yuan Xue; Huijuan Zhao; Yukari Tanikawa; Yukio Yamada
    Progress in Biomedical Optics and Imaging - Proceedings of SPIE, 6434巻, 出版日 2007年, 査読付, Fluorescence diffuse optical tomography (DOT) has attracted many attentions from the community of biomedical imaging, since it provides effective enhancement in imaging contrast. This modality is now rapidly evolving as a potential means of monitoring molecular events in small living organisms with help of molecule-specific contrast agents, referred to as fluorescence molecular tomography (FMT). FMT could greatly promote pathogenesis research, drug development, and therapeutic intervention. Although FMT in steady-state and frequency-domain modes have been promisingly demonstrated, the extension to time-domain scheme is imminent for its several unique advantages over the others. By extending the previously developed generalized pulse spectrum technique (GPST) for time-domain DOT, we propose a linear, featured-data image reconstruction algorithm for time-domain FMT that can simultaneously reconstruct both fluorescent yield and lifetime images, and validate the methodology with simulated data.
    研究論文(国際会議プロシーディングス), 英語
  • Fluorescence diffuse optical tomography by full time-resolved scheme
    Feng Gao; Hui Miao; Huijuan Zhao; Yukari Tanikawa; Yukio Yamada
    Progress in Biomedical Optics and Imaging - Proceedings of SPIE, 6434巻, 出版日 2007年, 査読付, A full time-resolved (TR) scheme that has been previously developed for diffuse optical tomography is extended to time-domain fluorescence diffuse optical tomography regime, based on the finite-element-finite-time-difference diffusion modeling and the Newtown-Raphson inversion method. We validate the proposed methodology using simulated data and demonstrate its capability of simultaneously recovering the fluorescent yield and lifetime, as well as its superiority of improving quantitative accuracy and spatial resolution of reconstruction to the featured-data one. The full time-resolved scheme helps set up the 'gold standard' for evaluating the performance of the other featured-data ones, and is more practically feasible in molecular imaging than in generic diffuse optical tomography due to availability of the difference measuring.
    研究論文(国際会議プロシーディングス), 英語
  • A linear GPST-based scheme for time-domain fluorescence molecular tomography
    Feng Gao; Yuan Xue; Huijuan Zhao; Yukari Tanikawa; Yukio Yamada
    OPTICAL TOMOGRAPHY AND SPECTROSCOPY OF TISSUE VII, SPIE-INT SOC OPTICAL ENGINEERING, 6434巻, 出版日 2007年, 査読付, Fluorescence diffuse optical tomography (DOT) has attracted many attentions from the community of biomedical imaging, since it provides effective enhancement in imaging contrast. This modality is now rapidly evolving as a potential means of monitoring molecular events in small living organisms with help of molecule-specific contrast agents, referred to as fluorescence molecular tomography (FMT). FMT could greatly promote pathogenesis research, drug development, and therapeutic intervention. Although FMT in steady-state and frequency-domain modes have been promisingly demonstrated, the extension to time-domain scheme is imminent for its several unique advantages over the others. By extending the previously developed generalized pulse spectrum technique (GPST) for time-domain DOT, we propose a linear, featured-data image reconstruction algorithm for time-domain FMT that can simultaneously reconstruct both fluorescent yield and lifetime images, and validate the methodology with simulated data.
    研究論文(国際会議プロシーディングス), 英語
  • Fluorescence diffuse optical tomography by full time-resolved scheme
    Feng Gao; Hui Miao; Huijuan Zhao; Yukari Tanikawa; Yukio Yamada
    OPTICAL TOMOGRAPHY AND SPECTROSCOPY OF TISSUE VII, SPIE-INT SOC OPTICAL ENGINEERING, 6434巻, 出版日 2007年, 査読付, A full time-resolved (TR) scheme that has been previously developed for diffuse optical tomography is extended to time-domain fluorescence diffuse optical tomography regime, based on the finite-element-finite-time-difference diffusion modeling and the Newtown-Raphson inversion method. We validate the proposed methodology using simulated data and demonstrate its capability of simultaneously recovering the fluorescent yield and lifetime, as well as its superiority of improving quantitative accuracy and spatial resolution of reconstruction to the featured-data one. The full time-resolved scheme helps set up the 'gold standard' for evaluating the performance of the other featured-data ones, and is more practically feasible in molecular imaging than in generic diffuse optical tomography due to availability of the difference measuring.
    研究論文(国際会議プロシーディングス), 英語
  • Time-domain fluorescence diffuse optical tomography utilizing generalized pulse-spectrum technique
    A. Marjono; S. Okawa; F. Gao; Y. Yamada
    Proceedings of SPIE Vol. 6434, BiOS2007, 6434巻, 出版日 2007年01月, 査読付
    研究論文(国際会議プロシーディングス), 英語
  • Measurement of temperature differences between micro-regions in water using near-infrared spectroscopy
    Naoto Kakuta; Atsushi Ozaki; Fuguo Li; Hidenobu. Arimoto; Yuldo Yamada
    2007 ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY, VOLS 1-16, IEEE, 掲載ページ 4564-+, 出版日 2007年, 査読付, We have developed a method for measuring the temperature of micro-regions in aqueous solutions using near-infrared spectroscopy that enables us to measure the temperature of biological cells, tissues, and biochemical solutions in vitro. The measurement principle is based on the fact that the peak wavelength of the water absorption band with its center near 1450 nm shifts with changes in temperature. The measurement system, which consists of a biological microscope and two spectrophotometers, can measure respective absorbance spectra for two areas that are each 80 mu m in diameter. We formed the temperature distribution in a 500-mu m thick water film by heating an immersed Nichrome wire and measured the temperature difference between the two areas. The results of the measurement were compared to a calculated temperature distribution.
    研究論文(国際会議プロシーディングス), 英語
  • Noninvasive near-infrared blood glucose monitoring using a calibration model built by a numerical simulation method: Trial application to patients in an intensive care unit
    Katsuhiko Maruo; Tomohiro Oota; Mitsuhiro Tsurugi; Takehiro Nakagawa; Hidenobu Arimoto; Mineji Hayakawa; Mamoru Tamura; Yukihiro Ozaki; Yukio Yamada
    APPLIED SPECTROSCOPY, SOC APPLIED SPECTROSCOPY, 60巻, 12号, 掲載ページ 1423-1431, 出版日 2006年12月, 査読付, We have applied a new methodology for noninvasive continuous blood glucose monitoring, proposed in our previous paper, to patients in ICU (intensive care unit), where strict controls of blood glucose levels are required. The new methodology can build calibration models essentially from numerical simulation, while the conventional methodology requires pre-experiments such as sugar tolerance tests, which are impossible to perform on ICU patients in most cases. The in vivo experiments in this study consisted of two stages, the first stage conducted on healthy subjects as preliminary experiments, and the second stage on ICU patients. The prediction performance of the first stage was obtained as a correlation coefficient (r) of 0.71 and standard error of prediction (SEP) of 28.7 mg/dL. Of the 323 total data, 71.5% were in the A zone, 28.5% were in the B zone, and none were in the C, D, and E zones for the Clarke error-grid analysis. The prediction performance of the second stage was obtained as an r of 0.97 and SEP of 27.2 mg/dL. Of the 304 total data, 80.3% were in the A zone, 19.7% were in the B zone, and none were in the C, D, and E zones. These prediction results suggest that the new methodology has the potential to realize a noninvasive blood glucose monitoring system using near-infrared spectroscopy (LAIRS) in ICUs. Although the total performance of the present monitoring system has not yet reached a satisfactory level as a stand-alone system, it can be developed as a complementary system to the conventional one used in ICUs for routine blood glucose management, which checks the blood glucose levels of patients every few hours.
    研究論文(学術雑誌), 英語
  • A linear, featured-data scheme for image reconstruction in time-domain fluorescence molecular tomography
    Feng Gao; Huijuan Zhao; Yukari Tanikawa; Yukio Yamada
    OPTICS EXPRESS, OPTICAL SOC AMER, 14巻, 16号, 掲載ページ 7109-7124, 出版日 2006年08月, 査読付, Fluorescence diffuse optical tomography (DOT) has attracted many attentions from the community of biomedical imaging, since it provides effective enhancement in imaging contrast. This modality is now rapidly evolving as a potential means of monitoring molecular events in small living organisms with help of molecule-specific contrast agents, referred to as fluorescence molecular tomography (FMT). FMT could greatly promote pathogenesis research, drug development, and therapeutic intervention. Although FMT in steady-state and frequency-domain modes have been heavily investigated, the extension to time-domain scheme is imminent for its several unique advantages over the others. By extending the previously developed generalized pulse spectrum technique for time-domain DOT, we propose a linear, featured-data image reconstruction algorithm for time-domain FMT that can simultaneously reconstruct both fluorescent yield and lifetime images of multiple fluorephores, and validate the methodology with simulated data. (c) 2006 Optical Society of America
    研究論文(学術雑誌), 英語
  • New methodology to obtain a calibration model for noninvasive near-infrared blood glucose monitoring
    K Maruo; T Oota; M Tsurugi; T Nakagawa; H Arimoto; M Tamura; Y Ozaki; Y Yamada
    APPLIED SPECTROSCOPY, SOC APPLIED SPECTROSCOPY, 60巻, 4号, 掲載ページ 441-449, 出版日 2006年04月, 査読付, This paper reports new methodology to obtain a calibration model for noninvasive blood glucose monitoring using diffuse reflectance near-infrared (NIR) spectroscopy. Conventional studies of noninvasive blood glucose monitoring with NIR spectroscopy use a calibration model developed by in vivo experimental data sets. In order to create a calibration model, we have used a numerical simulation of light propagation in skin tissue to obtain simulated NIR diffuse reflectance spectra. The numerical simulation method enables us to design parameters affecting the prediction of blood glucose levels and their variation ranges for a data set to create a calibration model using multivariate analysis without any in vivo experiments in advance. By designing the parameters and their variation ranges appropriately, we can prevent a calibration model from chance temporal correlations that are often observed in conventional studies using NIR spectroscopy. The calibration model (regression coefficient vector) obtained by the numerical simulation has a characteristic positive peak at the wavelength around 1600 nm. This characteristic feature of the regression coefficient vector is very similar to those obtained by our previous in vitro and in vivo experimental studies. This positive peak at around 1600 nm also corresponds to the characteristic absorption band of glucose. The present study has reinforced that the characteristic absorbance of glucose at around 1600 nm is useful to predict the blood glucose level by diffuse reflectance NIR spectroscopy. We have validated this new calibration methodology using in vivo experiments. As a result, we obtained a coefficient of determination, r(2), of 0.87 and a standard error of prediction (SEP) of 12.3 mg/dL between the predicted blood glucose levels and the reference blood glucose levels for all the experiments we have conducted. These results of ill vivo experiments indicate that if the parameters and their vibration ranges are appropriately taken into account in a numerical simulation, the new calibration methodology provides us with a very good calibration model that can predict blood glucose levels with small errors without conducting any experiments in advance to create a calibration model for each individual patient. This new calibration methodology using numerical simulation has promising potential for NIR spectroscopy, especially for noninvasive blood glucose monitoring.
    研究論文(学術雑誌), 英語
  • Theoretical and experimental study on near infrared time-resolved optical diffuse tomography
    Huijuan Zhao; Feng Gao; Yukari Tanikawa; Yukio Yamada
    Progress in Biomedical Optics and Imaging - Proceedings of SPIE, 6163巻, 出版日 2006年, 査読付, Parts of the works of our group in the past five years on near infrared time-resolved (TR) optical tomography are summarized in this paper. The image reconstruction algorithm is based on Newton Raphson scheme with a datatype R generated from modified Generalized Pulse Spectrum Technique. Firstly, the algorithm is evaluated with simulated data from a 2-D model and the datatype R is compared with other popularly used datatypes. In the second part of the paper, the in vitro and in vivo NIR DOT imaging on a chicken leg and a human forearm, respectively are presented for evaluating both the image reconstruction algorithm and the TR measurement system. The third part of this paper is about the differential pathlength factor of human head while monitoring head activity with NIRS and applying the modified Lambert-Beer law. Benefiting from the TR system, the measured DPF maps of the three import areas of human head are presented in this paper.
    研究論文(国際会議プロシーディングス), 英語
  • Influences of target size and contrast on near Infrared diffuse optical tomography: A comparison between featured-data and full time-resolved schemes
    Feng Gao; Huijuan Zhao; Yukari Tanikawa; Kazuhiro Homma; Yukio Yamada
    Progress in Biomedical Optics and Imaging - Proceedings of SPIE, 6047巻, 出版日 2006年, 査読付, Our recent DOT experiments on human lower legs and forearms are presented using the time-resolved measuring system and image reconstruction algorithm based on the modified generalized pulse spectrum technique. It was shown that the the spatial resolution and quantitativeness of the resultant images, including, was rather poor, and the interior blood vessels invisible in the absorption images. To clarify this issue, the influences of target contrast and size on the image reconstruction were investigated with simulated data. We have found that the quantitativeness of the reconstructed optical properties was prone to be spoiled by the small size ratio and high contrast of the interior targets to the background, and the incompleteness of information embedded in the featured data-types, evidently answers for the degradation of the image quality. It was shown in a further simulative investigation that the image quality could be substantially improved by making full use of the time-resolved data.
    研究論文(国際会議プロシーディングス), 英語
  • Theoretical and experimental study on near infrared time-resolved optical diffuse tomography - art. no. 61630G
    Huijuan Zhao; Feng Gao; Yukari Tanikawa; Yukio Yamada
    Saratov Fall Meeting 2005: Optical Technologies in Biophysics and Medicine VII, SPIE-INT SOC OPTICAL ENGINEERING, 6163巻, 掲載ページ G1630-G1630, 出版日 2006年, 査読付, Parts of the works of our group in the past five years on near infrared time-resolved (TR) optical tomography are summarized in this paper. The image reconstruction algorithm is based on Newton Raphson scheme with a datatype R generated from modified Generalized Pulse Spectrum Technique. Firstly, the algorithm is evaluated with simulated data from a 2-D model and the datatype R is compared with other popularly used datatypes. In the second part of the paper, the in vitro and in vivo NIR DOT imaging on a chicken leg and a human forearm, respectively are presented for evaluating both the image reconstruction algorithm and the TR measurement system. The third part of this paper is about the differential pathlength factor of human head while monitoring head activity with NIRS and applying the modified Lambert-Beer law. Benefiting from the TR system, the measured DPF maps of the three import areas of human head are presented in this paper.
    研究論文(国際会議プロシーディングス), 英語
  • Influences of target size and contrast on near infrared diffuse optical tomography: a comparison between featured-data and full time-resolved schemes
    Feng Gao; Huijuan Zhao; Yukari Tanikawa; Kazuhiro Homma; Yukio Yamada
    FOURTH INTERNATIONAL CONFERENCE ON PHOTONICS AND IMAGING IN BIOLOGY AND MEDICINE, PTS 1 AND 2, SPIE-INT SOC OPTICAL ENGINEERING, 6047巻, 出版日 2006年, 査読付, Our recent DOT experiments on human lower legs and forearms are presented using the time-resolved measuring system and image reconstruction algorithm based on the modified generalized pulse spectrum technique. It was shown that die the spatial resolution and quantitativeness of the resultant images, including, was rather poor, and the interior blood vessels invisible in the absorption images. To clarify this issue, the influences of target contrast and size on die image reconstruction were investigated with simulated data. We have found that the quantitativeness of the reconstructed optical properties was prone to be spoiled by the small size ratio and high contrast of the interior targets to the background. and die incompleteness of information embedded in the featured data-types, evidently answers for the degradation of the image quality. It was shown in a further simulative investigation that the image quality could be substantially improved by making full use of the time-resolved data.
    研究論文(国際会議プロシーディングス), 英語
  • Simple algorithm for the measurement of absorption coefficients of a two-layered medium by spatially resolved and time-resolved reflectance
    M Shimada; Y Hoshi; Y Yamada
    APPLIED OPTICS, OPTICAL SOC AMER, 44巻, 35号, 掲載ページ 7554-7563, 出版日 2005年12月, 査読付, An inversion procedure for the recovery of absorption coefficients of a two-layered semi-infinite diffusive medium by use of time-resolved reflectance measured at two different source-detector distances is proposed. The inversion procedure is based on the property of the photon diffusion equation; i.e., the solution of the diffusion equation for the time-resolved reflectance measured at a longer source-detector distance coincides with that measured at a shorter one by a proper temporal, spatial, and intensity transformation. This inversion procedure, used together with the results of one set of Monte Carlo simulations, is validated as working well when the values of the scattering coefficients of the two layers and the thickness of the first layer are within a range of interest in tissue optics. (c) 2005 Optical Society of America.
    研究論文(学術雑誌), 英語
  • Influences of target size and contrast on near infrared diffuse optical tomography - a comparison between featured-data and full time-resolved schemes
    F Gao; HJ Zhao; Y Tanikawa; K Homma; Y Yamada
    OPTICAL AND QUANTUM ELECTRONICS, SPRINGER, 37巻, 13-15号, 掲載ページ 1287-1304, 出版日 2005年12月, 査読付, Our recent diffuse optical tomography experiments on human lower legs and forearms are presented using the time-resolved measuring system and image reconstruction algorithm based on the modified generalized pulse spectrum technique. It was shown that the spatial resolution and quantitativeness of the resultant images, was rather poor, and the interior blood vessels invisible in the absorption images. To clarify this issue, the influences of target contrast and size on the image reconstruction were investigated with simulated data. We have found that the quantitativeness of the reconstructed optical properties was prone to be spoiled by the small size ratio and high contrast of the interior targets to the background, and the incompleteness of information embedded in the featured data-types, evidently answers for the degradation of the image quality. It was shown in a further simulative investigation that the image quality could be substantially improved by making full use of the time-resolved data.
    研究論文(学術雑誌), 英語
  • Extraction of depth-dependent signals from time-resolved reflectance in layered turbid media
    C Sato; M Shimada; Y Yamada; Y Hoshi
    JOURNAL OF BIOMEDICAL OPTICS, SPIE-INT SOCIETY OPTICAL ENGINEERING, 10巻, 6号, 掲載ページ 064008(CID) (pp. 1-11), 出版日 2005年11月, 査読付, We try a new approach with near-IR time-resolved spectroscopy, to separate optical signals originated in the upper layer from those in the lower layer and to selectively determine the absorption coefficient (mu(a)) of each layer in a two-layered turbid medium. The difference curve in the temporal profiles of light attenuation between a target and a reference medium is divided into segments along the time axis, and a slope of each segment is calculated to determine the depth-dependent mu(a). The depth-dependent mu(a) values are estimated under various conditions in which mu(a) and the reduced scattering coefficient (mu(s)') of each layer are changed with a Monte Carlo simulation and in phantom experiments. Temporal variation of them represents the difference in mu(a) between two layers when mu(s)' of a reference is the same as that of the upper layer of the target. The discrepancies between calculated mu(a) and the real mu(a) depend on the ratio of the real mu(a) of the upper layer to that of the lower layer, and our approach enables us to estimate the ratio of mu(a) between the two layers. These results suggest the potential that mu(a) of the lower layer can be determined by our procedure. (C) 2005 Society of Photo-Optical Instrumentation Engineers.
    研究論文(学術雑誌), 英語
  • Time-resolved Fluorescence Diffuse Optical Tomography Utilizing Generalized Pulse Spectrum Technique
    Andhi Marjono; Feng Gao; Yukio Yamada
    Proceedings of 4th World Congress on Industrial Process Tomography, Vol. 2, 掲載ページ 619-624, 出版日 2005年09月, 査読付
    研究論文(国際会議プロシーディングス), 英語
  • The development of leukocyte counter using fluorescence imaging analysis
    T. Hirono; K. Yabusaki; Y. Yamada
    Optical and Quantum Electronics, 37巻, 8号, 掲載ページ 735-753, 出版日 2005年08月, 査読付
    研究論文(学術雑誌), 英語
  • Plasma-enhanced chemical vapor deposition method to coat micropipettes with diamond-like carbon
    N Kakuta; M Watanabe; Y Yamada; N Okuyama; K Mabuchi
    REVIEW OF SCIENTIFIC INSTRUMENTS, AMER INST PHYSICS, 76巻, 7号, 掲載ページ Paper No. 075109 (5 pages), 出版日 2005年07月, 査読付, This article provides a simple method for coating glass micropipettes with diamond-like carbon (DLC) through plasma-enhanced chemical vapor deposition. The apparatus uses a cathode that is a thin-metal-coated micropipette itself and an anode that is a meshed cylinder with its cylinder axis along the micropipette length. To produce a uniform plasma and prevent a temperature increase at the tip due to ion collision concentration, we investigated the effect of the height and diameter of the meshed cylindrical anode on the plasma. Intermittent deposition is also effective for inhibiting the temperature rise and producing high quality DLC films. Measured Raman spectra and electric resistivity indicate that a DLC film suitable for use as an insulating film can be produced on the micropipette. This coating method should also be useful for other extremely small probes. (c) 2005 American Institute of Physics.
    研究論文(学術雑誌), 英語
  • Time-resolved diffuse optical tomographic imaging for the provision of both anatomical and functional information about biological tissue
    HJ Zhao; F Gao; Y Tanikawa; K Homma; Y Yamada
    APPLIED OPTICS, OPTICAL SOC AMER, 44巻, 10号, 掲載ページ 1905-1916, 出版日 2005年04月, 査読付, We present in vivo images of near-infrared (NIR) diffuse optical tomography (DOT) of human lower legs and forearm to validate the dual functions of a time-resolved (TR) NIR DOT in clinical diagnosis, i.e., to provide anatomical and functional information simultaneously. The NIR DOT system is composed of time-correlated single-photon-counting channels, and the image reconstruction algorithm is based on the modified generalized pulsed spectral technique, which effectively incorporates the TR data with reasonable computation time. The reconstructed scattering images of both the lower legs and the forearm revealed their anatomies, in which the bones were clearly distinguished from the muscles. In the absorption images, some of the blood vessels were observable. In the functional imaging, a subject was requested to do handgripping exercise to stimulate physiological changes in the forearm tissue. The images of oxyhemoglobin, deoxyhemoglobin, and total hemoglobin concentration changes in the forearm were obtained from the differential images of the absorption at three wavelengths between the exercise and the rest states, which were reconstructed with a differential imaging scheme. These images showed increases in both blood volume and oxyhemoglobin concentration in the arteries and simultaneously showed hypoxia in the corresponding muscles. All the results have demonstrated the capability of TR NIR DOT by reconstruction of the absolute images of the scattering and the absorption with a high spatial resolution that finally provided both the anatomical and functional information inside bulky biological tissues. (c) 2005 Optical Society of America.
    研究論文(学術雑誌), 英語
  • マイクロポンプ用微量流量計の研究開発
    西山 尚; 小西義昭; 村上元章; 藤原真人; 角田直人; 山田幸生
    ライフサポート, 17巻, 1号, 掲載ページ 9-15, 出版日 2005年04月, 査読付
    研究論文(学術雑誌), 日本語
  • Time-resolved fluorescence diffuse optical tomography
    Andhi Marjono; Feng Gao; Yukio Yamada
    6th Asian-Pacific Conference on Biomedical Engineering, 掲載ページ PA-3-30, 出版日 2005年04月, 査読付
    研究論文(国際会議プロシーディングス), 英語
  • Study of Flowmeter using Water Absorption Spectrum Change
    H. Momoki; S. Kubota; H. Nishiyama; N. Kakuta; H. Ochiai; H. Arimoto; Y. Yamada
    The 6th KSME-JSME Thermal and Fluids Engineering Conference, 掲載ページ CE.03, 出版日 2005年03月, 査読付
    研究論文(国際会議プロシーディングス), 英語
  • Depth profile of diffuse reflectance near-infrared spectroscopy for measurement of water content in skin.
    Hidenobu Arimoto; Mariko Egawa; Yukio Yamada
    Skin research and technology : official journal of International Society for Bioengineering and the Skin (ISBS) [and] International Society for Digital Imaging of Skin (ISDIS) [and] International Society for Skin Imaging (ISSI), 11巻, 1号, 掲載ページ 27-35, 出版日 2005年02月, 国際誌, BACKGROUND/PURPOSE: The penetration depth of light in diffuse reflectance near-infrared spectroscopy for measuring water content in skin is assessed both from theoretical and experimental points of view. METHODS: The Monte Carlo simulation was implemented to investigate the dependencies of the light penetration depth on a source-detector distance. To compare with the simulation results, an in vivo experiment for water contents of skin was performed introducing two different optical fiber probes. RESULTS: It is found that the minimum separation between a source and detector fibers influences largely the measurement depth. The larger separation leads to a deeper measurement depth at a particular wavelength. The measurement depth is also influenced fairly by the absorption coefficient of the tissue. The larger absorption coefficient results in a shallower measurement depth. CONCLUSION: The correlations between the water contents measured by the optical and capacitance techniques were discussed. The dependencies of the light penetration depth on the source-detector geometry and wavelength are presented.
    研究論文(学術雑誌), 英語
  • 828 近赤外光を用いたマイクロスケール領域の温度測定技術の開発(J13-2 生体の熱・物質輸送とその応用(2),J13 生体の熱・物質輸送とその応用,2005年度年次大会)
    李 富国; 角田 直人; 山田 幸生
    年次大会講演論文集, 一般社団法人日本機械学会, 2005巻, 掲載ページ 59-60, 出版日 2005年, We have proposed a method for non-invasively measuring the temperature changes of water in a micro-region using near infrared (NIR) light. The goal of this study is to measure the temperature changes of biological cells or tissues. This method is on the basis of the phenomenon that the NIR absorption spectrum of water depends on temperature. Absorbance spectra in the wavelength range of 1300-2000nm of water with a thickness of 100 and 500μm were measured by a micro-spectrometer. The measured spectra with temperature-dependence were calibrated using a regression analysis. The standard error of calibration was 0.30℃ for 100μm-thickness.
    日本語
  • 829 近赤外光を用いた生体組織の水分量計測(J13-2 生体の熱・物質輸送とその応用(2),J13 生体の熱・物質輸送とその応用,2005年度年次大会)
    北野 正典; 中村 優一; PILT Kristjan; 有本 英伸; 角田 直人; 山田 幸生
    年次大会講演論文集, 一般社団法人日本機械学会, 2005巻, 掲載ページ 61-62, 出版日 2005年, Patients of kidney disease remove excess water by hemodialysis. In hemodialysis, blood pressure may fall and the patients may suffer from hypovolemic shock, because body fluid removal rate is normally larger than plasma refilling rate. The aim of our research is to measure water content in issue in order to prevent the hypovolemic shock and to know how much water has to be removed quantitatively. We employ a technique using near infrared spectroscopy for this purpose. It will have advantages of being real-time, noninvasive and continuous.
    日本語
  • 201 細胞熱計測のための微小熱電対プローブの開発とその応用(OS1-04 : 生体マイクロ・ナノ新技術(1),マイクロ・ナノバイオメカニクス)
    渡邊 まゆ; 角田 直人; 土谷 遊; 満渕 邦彦; 山田 幸生
    バイオエンジニアリング学術講演会・セミナー講演論文集, 一般社団法人日本機械学会, 2004巻, 掲載ページ 39-40, 出版日 2005年
    日本語
  • 412 近赤外光を用いた光マッピング法のシミュレーション(GS-03 : 非侵襲計測技術)
    倉増 大士; MARJONO Andhi; 角田 直人; 山田 幸生
    バイオエンジニアリング学術講演会・セミナー講演論文集, 一般社団法人日本機械学会, 2004巻, 掲載ページ 155-156, 出版日 2005年
    日本語
  • 433 マイクロピペットへのDiamond-like Carbonコーティング技術の開発(GS-11 : 関節と潤滑・摩耗(2))
    角田 直人; 奥山 直樹; 渡邊 まゆ; 土谷 遊; 山田 幸生
    バイオエンジニアリング学術講演会・セミナー講演論文集, 一般社団法人日本機械学会, 2004巻, 掲載ページ 365-366, 出版日 2005年
    日本語
  • Influences from relative size and absorption contrast of an inhomogeneity on NIR diffuse optical image reconstruction
    Huijuan Zhao; Feng Gao; Yukari Tanikawa; Kazuhiro Homma; Yukio Yamada
    Progress in Biomedical Optics and Imaging - Proceedings of SPIE, 5693巻, 掲載ページ 483-494, 出版日 2005年, 査読付, Near infrared (NIR) diffused optical tomography (DOT) is emerging as a potential tool of non-invasively diagnosing woman breast cancers, neonatal brain hypoxia, and other human organ diseases. The intensive and worldwide investigations in theory and experiment have revealed the possibility of NIR DOT in providing both anatomical and functional information of biological tissue simultaneously, which is important for distinguishing between healthy and diseased tissues, such as benign and malignant tumors. In this paper, our recent DOT experiments on human lower legs and forearms are presented using our time-resolved measuring system and image reconstruction algorithm based on the modified generalized pulse spectrum technique. It was found that the image quality in the experiments, including both the spatial resolution and the quantitativeness of the targets, was rather poor, and the interior blood vessels undisclosed in the absorption images. To clarify this issue, the influences of target contrast and size on the image reconstruction were investigated with simulated data. We have accordingly obtained the following observations: the quantitativeness of the reconstructed optical properties was prone to be spoiled by the small size ratio and high contrast of the interior targets (such as blood vessels) to the background, and the incompleteness of information embedded in the featured data-types, in addition to the experimental noise, evidently answers for the degradation of the spatial resolution and quantitativeness. It was shown in a further simulative investigation that the image quality could be substantially improved by making full use of the time-resolved data.
    研究論文(国際会議プロシーディングス), 英語
  • Data optimization for enhancing robustness of time-resolved reflectance diffuse optical tomography to optode position uncertainty
    Feng Gao; Huijuan Zhao; Yukari Tanikawa; Yukio Yamada
    Progress in Biomedical Optics and Imaging - Proceedings of SPIE, 5693巻, 掲載ページ 450-458, 出版日 2005年, 査読付, The absolute diffuse optical tomography (DOT) has been rather difficult to achieve due to the problems arising upon the robustness of the algorithm to uncertainties in measuring conditions. Alternatively, the differential imaging scheme was applied to reconstruct a difference image between a target and a baseline reference from the difference data. Nevertheless, the absolute imaging scheme is desirable for unavailability of the reference in many situations. The absolute imaging usually uses intensity-independent data-type, which has been popularly the mean time of flight (TOF) in time-resolved (TR) detection, to avoid absolute instrument scaling. A problem with the mean TOF is its is insufficient sensitivity to deep absorption change to cope with the measuring noises, such as uncertainty of the optode positions. Therefore seeking for more robust data-type has been a key task in the community. We have previously developed an image reconstruction algorithm for TR-DOT, based on the modified generalized pulse spectrum technique (GPST), where the ratio between the Laplace-transformed TR re-emissions at two real-domain frequencies is used as the data-type. It is computationally the same efficient as the mean TOF but offers a potentiality to enhance noise-robustness by optimizing the working frequencies. We demonstrate here that the robustness of this data-type to optode position uncertainty can be substantially increased by enlarge the difference between the two working frequencies. We optimize the working frequencies within the range of physical sense and numerically validate the method for brain-simulating two-layer geometry using the TR reflected light.
    研究論文(国際会議プロシーディングス), 英語
  • Measurement of the anisotropy parameter of nails in the wavelength range from 900 nm to 1600 nm
    M Ueno; Y Mashita; H Arimoto; N Kakuta; Y Yamada
    2005 PACIFIC RIM CONFERENCE ON LASERS AND ELECTRO-OPTICS, IEEE, 掲載ページ 593-594, 出版日 2005年, 査読付, We measured the anisotropy parameter of nails in the near infrared wavelength range from 900 nm to 1600 nm with an accuracy of a few percent and found that it increases with the wavelength.
    研究論文(国際会議プロシーディングス), 英語
  • Photon migration in biological tissues and diffuse optical imaging
    Y Yamada
    Saratov Fall Meeting 2004: Optical Technologies in Biophysics and Medicine VI, SPIE-INT SOC OPTICAL ENGINEERING, 5771巻, 掲載ページ 15-27, 出版日 2005年, 査読付, Fundamental phenomenon of photon migration in tissues and its development to diffuse optical imaging are reviewed in present paper. Possible applications of optical diffuse imaging in medicine are discussed.
    研究論文(国際会議プロシーディングス), 英語
  • Influences from relative size and absorption contrast of an inhomogeneity on NIR diffuse optical image reconstruction
    HJ Zhao; F Gao; Y Tanikawa; K Homma; Y Yamada
    Optical Tomography and Spectroscopy of Tissue VI, SPIE-INT SOC OPTICAL ENGINEERING, 5693巻, 掲載ページ 483-494, 出版日 2005年, 査読付, Near infrared (NIR) diffused optical tomography (DOT) is emerging as a potential tool of non-invasively diagnosing woman breast cancers, neonatal brain hypoxia, and other human organ diseases. The intensive and worldwide investigations in theory and experiment have revealed the possibility of NIR DOT in providing both anatomical and functional information of biological tissue simultaneously, which is important for distinguishing between healthy and diseased tissues, such as benign and malignant tumors. In this paper, our recent DOT experiments on human lower legs and forearms are presented using our time-resolved measuring system and image reconstruction algorithm based on the modified generalized pulse spectrum technique. It was found that the image quality in the experiments, including both the spatial resolution and the quantitativeness of the targets, was rather poor, and the interior blood vessels undisclosed in the absorption images. To clarify this issue, the influences of target contrast and size on the image reconstruction were investigated with simulated data. We have accordingly obtained the following observations: the quantitativeness of the reconstructed optical properties was prone to be spoiled by the small size ratio and high contrast of the interior targets (such as blood vessels) to the background, and the incompleteness of information embedded in the featured data-types, in addition to the experimental noise, evidently answers for the degradation of the spatial resolution and quantitativeness. It was shown in a further simulative investigation that the image quality could be substantially improved by making full use of the time-resolved data.
    研究論文(国際会議プロシーディングス), 英語
  • Data optimization for enhancing robustness of time-resolved reflectance diffuse optical tomography to optode position uncertainty
    F Gao; HJ Zhao; Y Tanikawa; Y Yamada
    Optical Tomography and Spectroscopy of Tissue VI, SPIE-INT SOC OPTICAL ENGINEERING, 5693巻, 掲載ページ 450-458, 出版日 2005年, 査読付, The absolute diffuse optical tomography (DOT) has been rather difficult to achieve due to the problems arising upon the robustness of the algorithm to uncertainties in measuring conditions. Alternatively, the differential imaging scheme was applied to reconstruct a difference image between a target and a baseline reference from the difference data. Nevertheless, the absolute imaging scheme is desirable for unavailability of the reference in many situations. The absolute imaging usually uses intensity-independent data-type, which has been popularly the mean time of flight (TOF) in time-resolved (TR) detection, to avoid absolute instrument scaling. A problem with the mean TOF is its is insufficient sensitivity to deep absorption change to cope with the measuring noises, such as uncertainty of the optode positions. Therefore seeking for more robust data-type has been a key task in the community. We have previously developed an image reconstruction algorithm for TR-DOT, based on the modified generalized pulse spectrum technique (GPST), where the ratio between the Laplace-transformed TR re-emissions at two real-domain frequencies is used as the data-type. It is computationally the same efficient as the mean TOF but offers a potentiality to enhance noise-robustness by optimizing the working frequencies. We demonstrate here that the robustness of this data-type to optode position uncertainty can be substantially increased by enlarge the difference between the two working frequencies. We optimize the working frequencies within the range of physical sense and numerically validate the method for brain-simulating two-layer geometry using the TR reflected light.
    研究論文(国際会議プロシーディングス), 英語
  • Micro-thermocouple probe for measurement of cellular thermal responses
    M. S. Watanabe; N. Kakuta; K. Mabuchi; Y. Yamada
    2005 27th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, Vols 1-7, IEEE, 掲載ページ 4858-4861, 出版日 2005年, 査読付, We have produced micro-thermocouple probes for the measurement of cellular thermal responses. Cells generate heat with their metabolisms and more heat with reactions to a certain physical or chemical stimulation. Therefore, the analysis of the cellular thermal responses would provide new physiological information. However, a real-time thermal measurement technique on a target of a single cell has not been established. In this study, glass micropipettes, which are widely used in bioengineering and medicine, are used for the base of the thermocouple probes. Using microfabrication techniques, the junction of two different metal films is formed at the micropipette tip with a diameter of 1 mu m. This probe can inject a chemical substance into a cell and to detect its subsequent temperature changes simultaneously.
    研究論文(国際会議プロシーディングス), 英語
  • In vivo NIR time-resolved measurements of human parietal region enhanced with indocyanine green as a contrast agent
    Yukari Tanikawa; Huijuan Zhao; Feng Gao; Kaoru Sakatani; Yoko Hoshi; Chie Sato; Yukio Yamada
    Pacific Rim Conference on Lasers and Electro-Optics, CLEO - Technical Digest, 2005巻, 掲載ページ 989-990, 出版日 2005年, 査読付, In vivo measurements of human parietal region were carried out by using a NIR time-resolved diffuse optical imaging system. Indocyanine green was injected intravenously as a contrast agent to check its possibility to enhance images.
    研究論文(国際会議プロシーディングス), 英語
  • Measurement of the anisotropy parameter of nails in the wavelength range from 900 nm to 1600 nm
    Masanori Ueno; Yukari Mashita; Hidenobu Arimoto; Naoto Kakuta; Yukio Yamada
    Pacific Rim Conference on Lasers and Electro-Optics, CLEO - Technical Digest, 2005巻, 掲載ページ 993-994, 出版日 2005年, 査読付, We measured the anisotropy parameter of nails in the near infrared wavelength range from 900 nm to 1600 nm with an accuracy of a few percent and found that it increases with the wavelength.
    研究論文(国際会議プロシーディングス), 英語
  • A method for measurement of water temperature in micro-region using near infrared light
    N. Kakuta; F. Li; Y. Yamada
    2005 27th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, Vols 1-7, IEEE, 掲載ページ 3145-3148, 出版日 2005年, 査読付, We have proposed a method for non-invasively measuring the temperature changes of water in a micro-region using near infrared (NIR) light. The goal of this study is to measure the temperature changes of biological cells or tissues. This method is on the basis of the phenomenon that the NIR absorption spectrum of water depends on temperature. First, in order to confirm whether a right irradiation for the temperature measurement itself affects the water temperature, we calculated the temperature rise caused by the optical absorption. Next, absorbance spectra in the wavelength range of 1300 - 2000 nm of water with a thickness of 100 and 500 mu m were measured by a micro-spectrometer. The measured spectra with temperature-dependence were calibrated using a regression analysis. The standard error of calibration was 0.6 degrees C for 100 mu m-thickness.
    研究論文(国際会議プロシーディングス), 英語
  • Micro-thermocouple probe for measurement of cellular thermal responses
    M. S. Watanabe; N. Kakuta; K. Mabuchi; Y. Yamada
    2005 27th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, Vols 1-7, IEEE, 掲載ページ 4858-4861, 出版日 2005年, 査読付, We have produced micro-thermocouple probes for the measurement of cellular thermal responses. Cells generate heat with their metabolisms and more heat with reactions to a certain physical or chemical stimulation. Therefore, the analysis of the cellular thermal responses would provide new physiological information. However, a real-time thermal measurement technique on a target of a single cell has not been established. In this study, glass micropipettes, which are widely used in bioengineering and medicine, are used for the base of the thermocouple probes. Using microfabrication techniques, the junction of two different metal films is formed at the micropipette tip with a diameter of 1 mu m. This probe can inject a chemical substance into a cell and to detect its subsequent temperature changes simultaneously.
    研究論文(国際会議プロシーディングス), 英語
  • 近赤外光を用いた無侵襲温度測定
    桃木秀幸; 有本英伸; 角田直人; 山田幸生
    電気学会論文誌, 124-C巻, 9号, 掲載ページ 1725-1730, 出版日 2004年09月, 査読付
    研究論文(学術雑誌), 日本語
  • Non-invasive temperature measurement of biological tissues by NIR spectroscopy
    Yukio Yamada; Hideyuki Momoki; Hidenobu Arimoto; Naoto Kakuta
    Fourth Inter-Institute Workshop on Diagnostic Imaging from Bench to Bedside at The National Institutes of Health, 掲載ページ Poster, 出版日 2004年09月, 査読付
    研究論文(国際会議プロシーディングス), 英語
  • Photon migration in tissues, diffuse optical imaging and their applications to biomedicine
    Y. Yamada; F. Gao; H. Zhao; Y. Tanikawa; K. Homma
    ICO’04, 掲載ページ 1-2, 出版日 2004年07月, 査読付
    研究論文(国際会議プロシーディングス), 英語
  • in vivo measurements and image reconstruction of human lower legs using NIR diffuse optical tomography
    Y. Tanikawa; H. Zhao; F. Gao; K. Homma; Y. Yamada
    ICO’04, 掲載ページ Poster 14D2-9, 出版日 2004年07月, 査読付
    研究論文(国際会議プロシーディングス), 英語
  • Optimizing data-type for absolute diffuse optical tomographic imaging using time-domain reflectance
    Feng Gao; Huijuan Zhao; Yukari Tanikawa; Yukio Yamada
    Biomedical Topical Meetings, Optical Society of America, 掲載ページ Poster WF44, 出版日 2004年04月, 査読付
    研究論文(国際会議プロシーディングス), 英語
  • Estimation of absorption coefficient of the lower layer in layered turbid media with time-resolved measurement
    C. Sato; M. Shimada; Y. Yamada; Y. Hoshi
    Biomedical Topical Meetings, Optical Society of America, 掲載ページ Poster ThF4, 出版日 2004年04月, 査読付
    研究論文(国際会議プロシーディングス), 英語
  • Optical tomographic mapping of cerebral haemodynamics by means of time-domain detection: methodology and phantom validation
    F Gao; HJ Zhao; Y Tanikawa; Y Yamada
    PHYSICS IN MEDICINE AND BIOLOGY, IOP PUBLISHING LTD, 49巻, 6号, 掲載ページ 1055-1078, 出版日 2004年03月, 査読付, One of the primary applications of diffuse optical imaging is to localize and quantify the changes in the cerebral oxygenation during functional brain activation. Up to now, data from an optical imager are simply presented as a two-dimensional (2D) topographic map using the modified Beer-Lambert law that assumes homogeneous optical properties beneath each optode. Due to the highly heterogeneous nature of the optical properties in the brain, the assumption is evidently invalid, leading to both low spatial resolution and inaccurate quantification in the assessment of haemodynamic changes. To cope with these difficulties, we propose a nonlinear tomographic image reconstruction algorithm for a two-layered slab geometry that uses time-resolved reflected light. The algorithm is based on the previously developed generalized pulse spectrum technique, and implemented within a semi-three-dimensional (3D) framework to conform to the topographic visualization and to reduce computational load. We demonstrate the advantages of the algorithm in quantifying simulated changes in haemoglobin concentrations and investigate its robustness to the uncertainties in the cortical structure and optical properties, as well as the effects of random noises on image quality. The methodology is also validated by experiments using a solid layered phantom.
    研究論文(学術雑誌), 英語
  • Diffuse optical tomography by use of time-resolved measurement
    Feng Gao; Huijuan Zhao; Yukari Tanikawa; Kazuhiro Homma; Yukio Yamada
    The 10th Conference of Peace through Mind / Brain Science, 掲載ページ Poster P-14, 出版日 2004年02月, 査読付
    研究論文(国際会議プロシーディングス), 英語
  • Diamond-like carbon coating on micropipettes
    N Kakuta; N Okuyama; M Watanabe; Y Imai; K Mabuchi; Y Yamada
    PROCEEDINGS OF THE 26TH ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY, VOLS 1-7, IEEE, 26巻, 掲載ページ 2454-2457, 出版日 2004年, 査読付, Based on glass micropipettes which are widely used in bioengineering and medicine, various micro-sensor probes could be produced by recent microfabrication techniques. Conductive surfaces of these sensor probes mostly need electrical insulating films coated on them, but it has been difficult to coat a high-quality and strong insulating film on a micro-acute probe such as a micropipette, especially on its tip. Therefore, we have employed diamond-like carbon (DLC) as an insulating film and developed a DLC coating method based on plasma chemical vapor deposition method. In the deposition apparatus, the cathode is the micropipette itself and the anode is a mesh cylinder with a central focus on the micropipette. In order to prevent the growing films from transformation due to high temperature at the tip, the voltage between the pair of electrodes is impressed intermittently. Raman spectrum and electrical resistivity measured here indicate that the deposited film is DLC and it can be worked well as an insulating film. The DLC coating method could be useful in micro-probe fabrications.
    研究論文(国際会議プロシーディングス), 英語
  • 膨張型金星気球の熱的振る舞いと浮遊解析(S65-2 宇宙用膜構造,S65 宇宙構造物)
    市川 和男; 山田 幸生; 角田 直人; 井筒 直樹
    年次大会講演論文集, 一般社団法人日本機械学会, 2004巻, 掲載ページ 439-440, 出版日 2004年, Since Venus has the high-density atmosphere of carbon dioxide, a floating balloon is possible and it can perform various kinds of science observation. An inflatable balloon filled with water for buoyancy is heated by the high temperature atmosphere and ground. This paper reports the thermal and floating behaviors of the balloon predicted by heat transfer and motion analyses. It has found that the balloon can float steadily at the estimated altitude of about 35 km
    日本語
  • バイオエンジニアリングにおける熱工学の現状と将来(熱工学最前線,F05 熱工学部門企画)
    山田 幸生
    年次大会講演資料集, 一般社団法人日本機械学会, 2004巻, 掲載ページ 118-119, 出版日 2004年, Thermal engineering plays important roles in bioengjneering covering from micro- to macro-scale heat and mass transfer including biochemistry. Current statuses of various fields in thermal engineering are reviewed and future prospects are discussed.
    日本語
  • Non-Invasive Measurements of Temperature Using near Infrared Light
    Hideyuki Momoki; Naoto Kakuta; Hidenobu Arimoto; Yukio Yamada
    IEEJ Transactions on Electronics, Information and Systems, 124巻, 9号, 掲載ページ 1725-1730, 出版日 2004年, 査読付, We have proposed a new method of measuring temperature of media containing water by near infrared spectroscopy and multivariate analysis. The peak wavelength of the water absorption band at about 1450 nm shifts with the change in temperature. By measuring the wavelength shift of the absorption band we can measure the temperature of media containing water whenever it is transparent like water solutions or turbid like biological tissues. Fundamental experiments have validated the proposed method. The measurement accuracy has been found to be less than 0.1 °C for pure water, 0.3 °C for turbid media with transmission measurement, and 0.6 °C for turbid media with reflection measurement. © 2004, The Institute of Electrical Engineers of Japan. All rights reserved.
    研究論文(学術雑誌), 英語
  • Simple algorithm to estimate the absorption coefficients of two-layered scattering media from the spatially- and time-resolved reflectance
    M. Shimada; Y. Yamada; Y. Hoshi
    SPIE Proc. Vol. 5321, 掲載ページ 1-2, 出版日 2004年01月, 査読付
    研究論文(国際会議プロシーディングス), 英語
  • Measurement of the optical properties of nails
    Y Mashita; M Ueno; M Ohmi; H Arimoto; N Kakuta; M Haruna; Y Yamada
    APBP 2004: SECOND ASIAN AND PACIFIC RIM SYMPOSIUM ON BIOPHOTONICS, PROCEEDINGS, IEEE, 掲載ページ 44-45, 出版日 2004年, 査読付, We have measured the scattering and the absorption coefficients of nails at wavelengths from 800 to 1900nm by the combination of integrating sphere measurements and an inverse Monte Carlo method. Also the dependences of these coefficients on surface roughness and humidity were investigated.
    研究論文(国際会議プロシーディングス), 英語
  • Diffusely scattered polarized light in turbid media: Monte Carlo simulation
    SP Wang; LQ Xu; H Li; Y Yamada
    APBP 2004: SECOND ASIAN AND PACIFIC RIM SYMPOSIUM ON BIOPHOTONICS, PROCEEDINGS, IEEE, 掲載ページ 40-41, 出版日 2004年, 査読付, Monte Carlo method was used to simulate the propagation behavior of 2-D Stokes vectors and Mueller matrices under various conditions. The effect of different incident polarization states, tissue optical parameters and Fresnel matrices at the boundary are fully considered.
    研究論文(国際会議プロシーディングス), 英語
  • Optical measurement of water content in tissue
    Y Nakamura; K Pilt; N Kakuta; H Arimoto; Y Yamada
    APBP 2004: SECOND ASIAN AND PACIFIC RIM SYMPOSIUM ON BIOPHOTONICS, PROCEEDINGS, IEEE, 掲載ページ 167-168, 出版日 2004年, 査読付, It is necessary for more appropriate hemodialysis treatment to know water content in tissue. We measured water content of Intralipid-20% solution which has similar optical properties to those of tissue, and showed the possibility to measure the water content in tissue in vivo.
    研究論文(国際会議プロシーディングス), 英語
  • The development of leukocyte counter using fluorescence imaging analysis
    T Hirono; K Yabusaki; Y Yamada
    APBP 2004: SECOND ASIAN AND PACIFIC RIM SYMPOSIUM ON BIOPHOTONICS, PROCEEDINGS, IEEE, 掲載ページ 213-214, 出版日 2004年, 査読付, Image cytometry centrifugation (ICC) method has been developed to enumerate residual leukocytes in transfusion blood products. Leukocyte counts by the ICC method were found to be consistent with those by the conventional Nageotte hemocytometry.
    研究論文(国際会議プロシーディングス), 英語
  • A comparative investigation of influences of target size and contrast on diffuse optical tomography by featured-data and full time-resolved reconstructions
    F Gao; HJ Zhao; Y Tanikawa; K Homma; Y Yamada
    APBP 2004: SECOND ASIAN AND PACIFIC RIM SYMPOSIUM ON BIOPHOTONICS, PROCEEDINGS, IEEE, 掲載ページ 144-145, 出版日 2004年, 査読付, This paper presents time-resolved diffuse optical tomographic imaging of human lower legs and forearms. To identify the sources that cause the low quantitativeness in the reconstructed images, a comparative study is carried out on reality-simulating numerical phantoms using both the featured-data and full time-resolved algorithms.
    研究論文(国際会議プロシーディングス), 英語
  • Study of non-invasive near-infrared blood glucose monitoring: estimation of weak absorbance change in skin tissue based on a Monte Carlo simulation
    T. Ohta; K. Maruo; M. Tarumi; H. Arimoto; M. Shimada; Y. Yamada
    掲載ページ A104, 出版日 2003年11月, 査読付
    研究論文(国際会議プロシーディングス), 英語
  • Noninvasive Blood Glucose Assay Using a Newly Developed Near-Infrared System
    K. Maruo; M. Tsurugi; J. Chin; T. Ohta; H. Arimoto; Y. Yamada; M. Tamura; M. Ishii; Y. Ozaki
    IEEE J. Slected Topics in Quantum Electronics, 9巻, 2号, 掲載ページ 322-330, 出版日 2003年08月, 査読付
    研究論文(学術雑誌), 英語
  • Simulation study of in vitro glucose measurement by NIR spectroscopy and a method of error reduction
    M Tarumi; M Shimada; T Murakami; M Tamura; M Shimada; H Arimoto; Y Yamada
    PHYSICS IN MEDICINE AND BIOLOGY, IOP PUBLISHING LTD, 48巻, 15号, 掲載ページ 2373-2390, 出版日 2003年08月, 査読付, The effects of some important factors on the blood glucose measurements by NIR spectroscopy are investigated by numerical simulation, and a method is proposed to significantly reduce the prediction errors induced by these effects. The changes in the absorbance spectra with the changes in the glucose concentration, temperature and scattering characteristics of background tissue are obtained by a Monte Carlo simulation of light propagation for the wavelength range from 1200 nm to 1800 nm. The glucose concentration is predicted by applying a multivariate analysis to the numerically simulated spectra. This process estimates the errors in the prediction of the glucose concentration induced by the temperature and scattering changes. It has been found that only 1degreesC change in the temperature or only 1% change in the scattering coefficient induces about 500 mg dl(-1) or 300 mg dl(-1) errors, respectively, in the prediction of the glucose concentration. These errors can be significantly reduced to less than 20 mg dl(-1) of the glucose concentration by incorporating the effects of the temperature and scattering characteristics on the spectra to the multivariate analysis.
    研究論文(学術雑誌), 英語
  • Image reconstruction for tomographic mapping of cerebral hemodynamics using time-domain detection
    F. Gao; H. Zhao; Y. Tanikawa; Y. Yamada
    SPIE Proceedings, 掲載ページ 5138-25, 出版日 2003年06月, 査読付
    研究論文(国際会議プロシーディングス), 英語
  • Spectroscopic blood component measurement by using reduced ranges of absorption spectra
    H. Arimoto; Y. Yamada
    SPIE Proceedings, 掲載ページ 5138-46, 出版日 2003年06月, 査読付
    研究論文(国際会議プロシーディングス), 英語
  • Optical transport process in turbid media and applications to optical imaging of tissues
    Y. Yamada
    掲載ページ ThW1-03, 出版日 2003年06月, 査読付
    研究論文(国際会議プロシーディングス), 英語
  • 散乱の非等方性を考慮した反射型時間分解法による生体組織の光学特性測定に関する検討
    田中健之; 谷川ゆかり; 荒木隆一郎; 山田幸生; 岡田英史
    光学, 応用物理学会分科会日本光学会, 32巻, 5号, 掲載ページ 328-335, 出版日 2003年05月, 査読付
    研究論文(学術雑誌), 日本語
  • Instrumental requirements for non-invasive blood glucose measurement using NIR spectroscopy
    H Arimoto; M Tarumi; Y Yamada
    OPTICAL REVIEW, OPTICAL SOC JAPAN, 10巻, 3号, 掲載ページ 161-165, 出版日 2003年05月, 査読付, The magnitude of spectral change in blood glucose measurements with diffuse reflectance spectroscopy is investigated. Spectral change is estimated by simulation of light propagation in skin tissue and measurements of absorbance spectra of aqueous glucose solution. Required sensitivity of spectrophotometers for monitoring change in the blood glucose concentration as small as 10 mg/dL has been obtained using the estimated change in the absorbance spectrum and mean pathlength of light in tissue.
    研究論文(学術雑誌), 英語
  • Solution of the time-dependent diffusion equation for layered diffusive media by the eigenfunction method
    F Martelli; A Sassaroli; S Del Bianco; Y Yamada; G Zaccanti
    PHYSICAL REVIEW E, AMER PHYSICAL SOC, 67巻, 5号, 掲載ページ 1-14, 出版日 2003年05月, 査読付, An exact solution of the time-dependent diffusion equation for the case of a two- and a three-layered finite diffusive medium is proposed. The method is based on the decomposition of the fluence rate in a series of eigenfunctions and upon the solution of the consequent transcendental equation for the eigenvalues obtained from the boundary conditions. Comparisons among the solution of the diffusion equation and the results of Monte Carlo simulations show the correctness of the proposed model.
    研究論文(学術雑誌), 英語
  • Temperature-insensitive measurement of glucose concentration based on near infrared spectroscopy and partial least squares analysis
    H Arimoto; M Tarumi; Y Yamada
    OPTICAL REVIEW, OPTICAL SOC JAPAN, 10巻, 2号, 掲載ページ 74-76, 出版日 2003年03月, 査読付, Temperature-insensitive partial least squares analysis for glucose measurement is presented based on Near Infrared spectroscopy in the wavelength range from 1,250 to 1,800 nm. Experiments are performed using aqueous glucose solutions. To create a temperature-insensitive prediction model, the glucose concentration and water temperature are varied independently. The results of the predicted glucose concentration agree well with the actual glucose concentration with an error of 4.4%.
    研究論文(学術雑誌), 英語
  • General programs for bio-heat and mass transfer analyses - Tissue element data generation based on the CFSV-model
    N Kakuta; Y Mizuta; Y Yamada
    PROCEEDINGS OF THE 25TH ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY, VOLS 1-4, IEEE, 25巻, 掲載ページ 2830-2833, 出版日 2003年, 査読付, This study aims to develop general programs, irrespective of the governing equations, schemes, grid structures, and vascular models, for numerical analyses of bioheat and mass transfer. We have used the CFSV-model proposed on the basis that every equation discretized for numerical analysis of three-dimensional continuous media is no other than the relation among quantities on elements such as Cells, Faces, Sides, and Vertices, to generate the data rile with the kind, category, serial number of the every tissue element, and the junction relation with its ambient elements. Since these data can be referred at ease in a program with some functions, it is effective to produce the program. The element data has been applied to a simple vascular model, and it can be useful for the numerical calculation.
    研究論文(国際会議プロシーディングス), 英語
  • 510 血液中水分濃度の光学的計測に関する基礎研究
    中村 優一; 角田 直人; 山田 幸生
    年次大会講演論文集, 一般社団法人日本機械学会, 2003巻, 掲載ページ 65-66, 出版日 2003年, Water as well as wastes is removed from the blood of patients under dialysis treatment. If the quantity of the removed water exceeds the limit by some reasons the probability of dangerous accidents becomes high. Therefore, it is highly desired to monitor the blood status continuously during dialysis treatment. This paper presents some results of a fundamental research of measurement of water content in blood using near infrared spectroscopy and multivariate analysis for the purpose of continuous blood monitoring.
    日本語
  • 428 細胞レベルの熱計測技術
    今井 友香; 角田 直人; 満渕 邦彦; 山田 幸生
    年次大会講演論文集, 一般社団法人日本機械学会, 2003巻, 掲載ページ 7-8, 出版日 2003年, We have developed a micro-thermocouple probe for measuring the cellular thermal responses. In addition to the metabolic heat generation, a cell generates heat by physical or chemical stimulus. If the measurement of such a heat generation becomes possible, it can contribute to the development of new medical technology in pharmaceutics and to the elucidation of physiology. The micro-thermocouple probe is fabricated by layering multiple metal thin films and electrical insulating films on a glass micropipette as a base, and it functions as a thermocouple and a microinjector simultaneously. The thermoelectric performance of the fabricated micro-thermocouple probe has been evaluated.
    日本語
  • Spectroscopic blood component measurement by using reduced ranges of absorption spectra
    H Arimoto; Y Yamada
    PHOTON MIGRATION AND DIFFUSE-LIGHT IMAGING, SPIE-INT SOC OPTICAL ENGINEERING, 5138巻, 掲載ページ 323-330, 出版日 2003年, 査読付, Predicting concentrations of aqueous glucose solutions using reduced wavelength components is investigated. The wavelengths are selected based on the second derivative of the near-infrared absorbance spectra. In the demonstration of the temperature-insensitive partial least squares analysis, good agreement between actual glucose concentrations and predicted values is verified.
    研究論文(国際会議プロシーディングス), 英語
  • The ability of NIR diffuse optical tomography in providing both anatomical and functional images
    HJ Zhao; F Gao; Y Tanikawa; K Homma; Y Yamada
    PHOTON MIGRATION AND DIFFUSE-LIGHT IMAGING, SPIE-INT SOC OPTICAL ENGINEERING, 5138巻, 掲載ページ 55-64, 出版日 2003年, 査読付, The experimental results of NIR optical tomographic imaging on human limbs are shown in this paper. The absolute absorption and scattering images roughly revealed the anatomical structure of the targets, where the bones were distinguished from the muscle. The images of the hemoglobin concentration changes calculated from differential image of absorption at two wavelengths showed the physiological phenomena during the forearm exercise.
    研究論文(国際会議プロシーディングス), 英語
  • Image reconstruction for tomographic mapping of cerebral hemodynamics using time-domain detection: simulation and phantom studies
    F Gao; HJ Zhao; Y Tanikawa; Y Yamada
    PHOTON MIGRATION AND DIFFUSE-LIGHT IMAGING, SPIE-INT SOC OPTICAL ENGINEERING, 5138巻, 掲載ページ 148-159, 出版日 2003年, 査読付, One of the primary applications of diffuse optical imaging is to localize the changes in the cerebral oxygenation during physical or mental activities. Up to now, data from an optical imager is simply presented as a two-dimensional (2-D) topographic map using the modified Beer-Lambert law that assumes the homogeneous optical properties beneath each optode. Due to the highly heterogeneous nature of the optical properties in the brain, the assumption are evidently invalid, leading to both low spatial resolution and inaccurate quantification in the assessment of hemodynamic changes.
    To cope with the difficulties, we propose a nonlinear image reconstruction algorithm for a two-layered slab geometry using time-resolved reflected light. The algorithm is based on the previously developed generalized pulse spectrum technique, and implemented within a semi three-dimensional (3-D) framework to conform to the topographic visualization and to reduce computational load. We demonstrate the advantages of the algorithm in quantifying simulated changes in hemoglobin concentrations and investigate its robustness to the uncertainties in the cortical structure and optical properties. The methodology is also validated with experiments on a layered phantom.
    研究論文(国際会議プロシーディングス), 英語
  • Instrumental requirements for blood glucose sensing based on diffuse reflectance NIR spectroscopy
    H Arimoto; T Ota; M Tarumi; Y Yamada
    OPTICAL DIAGNOSTICS AND SENSING IN BIOMEDICINE III, SPIE-INT SOC OPTICAL ENGINEERING, 4965巻, 掲載ページ 17-24, 出版日 2003年, 査読付, The study on the magnitude. of spectral change in blood glucose measurements with diffuse reflectance NIR, spectroscopy is presented. Spectral change is estimated by a Monte Carlo simulation and measurements of absorbance spectra of aqueous glucose solution. Required sensitivity of spectrophotometers for monitoring the change in the blood glucose concentration as small as 10mg/dL has been obtained using the estimated change in the absorbance spectrum and mean pathlength of light in tissue.
    研究論文(国際会議プロシーディングス), 英語
  • Optical property measurement of thin superficial tissue by using time-resolved spectroscopy
    K Tanaka; Y Tanikawa; R Araki; Y Yamada; E Okada
    DIAGNOSTIC OPTICAL SPECTROSCOPY IN BIOMEDICINE II, SPIE-INT SOC OPTICAL ENGINEERING, 5141巻, 掲載ページ 315-324, 出版日 2003年, 査読付, Recently, non-invasive diagnostic devices using infrared light have been developed and widely use for clinical applications. To develop these devices, optical properties of biological tissue are necessary. We proposed a new optical measurement method. By using time-resolved reflectance spectroscopy and Monte Carlo simulation for the analysis of light propagation in sample, it is considered that this new method is able to measure the optical properties of small biological tissues in vivo. In this study, we investigated the possible optical property measurements of a superficial layer using this new method. As the later part of the profile of time-resolved reflectance is influenced by the optical property of the deeper layer, a time-gating technique is necessary for the measurement of the optical properties of only the superficial layer in order to use the early profile of the time-resolved reflectance measurement. The function f (t), which is described in the new method, is used for evaluation of the measurement of the superficial layer. We suggest that by using the time-gating technique for the new method and a small source-detector spacing, the optical properties of the superficial layer with a thickness is more than source-detector spacing, can be obtained.
    研究論文(国際会議プロシーディングス), 英語
  • Development of a retractor for monitoring the oxygenation state of brain tissue
    Y Onodera; Y Yamada; K Sakatani; T Hori
    OXYGEN TRANSPORT TO TISSUE VOLUME XXIII, KLUWER ACADEMIC/PLENUM PUBL, 510巻, 掲載ページ 219-223, 出版日 2003年, 査読付
    研究論文(学術雑誌), 英語
  • Monte Carlo Simulation of Near Infrared Reflectance Spectroscopy in the Wavelength Range from 1000 nm to 1900 nm
    Kenji Iino; Katsuhiko Maruo; Hidenobu Arimoto; Koji Hyodo; Tetsu Nakatani; Yukio Yamada
    Optical Review, Optical Society of Japan, 10巻, 6号, 掲載ページ 600-606, 出版日 2003年, 査読付, We have calculated the characteristics of reflected near infrared light, which is incident on the skin surface, scattered in the skin tissue and detected, in the wavelength range from 1000 nm to 1900 nm. We have used a Monte Carlo method to calculate the propagation path, the average photon visit depth, the average photon path length, etc. for the cases of short source-detector distances, to which the Isotropic scattering approximation cannot be applied. An experiment to validate the simulation results was also conducted using a liquid phantom.
    研究論文(国際会議プロシーディングス), 英語
  • Development of a retractor for monitoring the oxygenation state of brain tissue
    Y Onodera; Y Yamada; K Sakatani; T Hori
    OXYGEN TRANSPORT TO TISSUE VOLUME XXIII, KLUWER ACADEMIC/PLENUM PUBL, 510巻, 掲載ページ 219-223, 出版日 2003年, 査読付
    研究論文(学術雑誌), 英語
  • Treatment of nevus using medical tattooing
    J Hata; M Shimada; Y Yamada; A Uchida; M Itoh; Y Nakayama; T Yatagai
    JOURNAL OF BIOMEDICAL OPTICS, SPIE-INT SOCIETY OPTICAL ENGINEERING, 8巻, 1号, 掲載ページ 93-101, 出版日 2003年01月, 査読付, Medical tattooing is used to color skin with a pigment loss. Currently, however, a trial-and-error scheme is employed to obtain the desired color appearance of tattooed skin because prediction of the color appearance is dependent on the experiences of medical doctors. We propose a method for predicting the color appearance of tattooed skin. Two trial dyes are first injected in the area of pigment loss, and the color appearance of a third dye to be injected can be predicted using measured spectrocolorimeter data and mathematical formula. The spectrocolorimeter measures the color appearances of the skin before and after tattooing using the first two dyes, and the mathematical formula calculates the color appearance of the tattooed skin using any third dye. In the derivation of the mathematical formula, light propagation in the skin has been modeled using the modified Lambert-Beer law considering the strong scattering of light by biological tissues. The proposed method was successfully validated by a preliminary tattooing of the skin to an area with pigment loss. Predicting the color appearance of tattooed skin significantly reduces the number of trial-and-error attempts required in the current methods. Medical tattooing using this method can also be applied to treat various skin color abnormalities such as leukoderma, intradermal nevi, and reconstructed nipples. (C) 2003 Society of Photo-Optical instrumentation Engineers.
    研究論文(学術雑誌), 英語
  • Reflectance-type image reconstruction algorithm for time-resolved optical tomography of cerebral hemodynamics
    F Gao; Y Tanikawa; HJ Zhao; Y Yamada
    OPTICAL TOMOGRAPHY AND SPECTROSCOPY OF TISSUE V, SPIE-INT SOC OPTICAL ENGINEERING, 4955巻, 掲載ページ 253-263, 出版日 2003年, 査読付, Optical imaging can be used for localizing the oxygenation changes in the cortex in response to physical or mental tasks, with the advantages of flexibility and low cost. Up to now, data from optical imager is simply presented as a two-dimensional (2-D) topographic map rather than being tomographically reconstructed onto the cerebral cortex, based on the assumptions that the optical properties beneath each optode pair are homogeneous and the modified Beer-Lambert law can be used. Due to the high heterogeneity of optical properties in the brain, the assumptions are evidently invalid, leading to both low spatial resolution and quantitative inaccuracy in the assessment of hemodynamic changes.
    To solve the problem, we propose a nonlinear image reconstruction algorithm for a two-layered slab geometry using time-resolved reflected light and demonstrate its advantages in quantifying simulated changes in hemoglobin concentrations. The algorithm is based on the previously developed generalized pulse spectrum technique, and implemented within a semi three-diensional (3-D) framework, where the changes of optical properties assumed invariable in depth, to conform to the topographic visualization and to reduce computational load. We also investigate the robustness of the algorithm to the uncertainties in the cortical structure and optical properties.
    研究論文(国際会議プロシーディングス), 英語
  • NIR time domain diffuse optical tomographic experiments on human forearm
    HJ Zhao; F Gao; Y Tanikawa; K Homma; Y Yamada
    OPTICAL TOMOGRAPHY AND SPECTROSCOPY OF TISSUE V, SPIE-INT SOC OPTICAL ENGINEERING, 4955巻, 掲載ページ 437-446, 出版日 2003年, 査読付, To date, the applications of near infrared (NIR) diffusion optical tomography (DOT) are mostly focused on the potential of imaging woman breast, human head hemodynamics and neonatal head. For the neonates, who are suffered from ischaemia or hemorrhages in brain, bedside monitoring of the cerebral perfusion situation, e.g., the blood oxygen saturation and blood volume, is necessary for avoiding permanent injure. NIR DOT is one of the promising tools because it is noninvasive, smaller in size, and moveable. Prior to achieving the ultimate goal of imaging infant brain and woman breast using DOT, in this paper, the developed methodologies are justified by imaging in vivo human forearms. The absolute absorption- and scattering-coefficient images revealed the inner structure of the forearm and the bones were clearly distinguished from the muscle. The differential images showed the changes in oxy-hemoglobin, deoxyhemoglobin and blood volume during the hand-gripping exercises, which are consistent with the physiological process reported on literatures.
    研究論文(国際会議プロシーディングス), 英語
  • Optical fiber arrangement of optical topography for spatial resolution improvement
    T Yamamoto; E Okada; F Kawaguchi; A Maki; Y Yamada; H Koizumi
    OPTICAL TOMOGRAPHY AND SPECTROSCOPY OF TISSUE V, SPIE-INT SOC OPTICAL ENGINEERING, 4955巻, 掲載ページ 487-496, 出版日 2003年, 査読付, In medical instrumentation, optical topography (OT) refers to the use of near-infrared spectroscopy for measuring brain function in systems. Arrays of optical fibers are attached to the scalps of subjects; infrared light is passed through the fibers, and changes in the reflections depict blood-volume changes in the cortex. In this study, the spatial resolution and locational accuracy of topographical images obtained by three arrangements of optical fibers was analyzed through simulation. Three arrangements, a "lattice arrangement" (LA), "double-density arrangement" (DA), and "quadruple density arrangement" (QA) were investigated. The density of spatial-sapling points is higher in the DA and QA than in the LA, i.e. the distance between sampling points for these arrangements were 21, 15 and 11 mm, respectively. The efficacy of these arrangements was evaluated. An adult head-structure phantom was prepared. The absorption coefficient in the phantom was varied to simulate brain activation in the cortex, and the resulting absorbance change (DeltaOD) was thus obtained. The 'activated' area in the overall measurement area was fixed and the DeltaOD at each of the sampling point in each arrangement was obtained. The resulting distributions of DeltaOD were spatially interpolated to obtain topographical images. The spatial resolution and locational accuracy was obtained for each of the images; the results indicated that the DA is the most efficacious of the three arrangements. An experimental DA-OT system was then built. Topographical images of motor-function activation obtained by this system and a commercial LA-based system were compared; the DA-OT system provided the higher spatial resolution.
    研究論文(国際会議プロシーディングス), 英語
  • Instrumental requirements for blood glucose sensing based on diffuse reflectance NIR spectroscopy
    H. Arimoto; T. Ota; M. Tarumi; Y. Yamada
    SPIE Proceedings, Vol. 4965, 掲載ページ 4965-03, 出版日 2003年01月, 査読付
    研究論文(国際会議プロシーディングス), 英語
  • The ability of NIR diffuse optical tomography in providing both anatomical and functional images
    H. Zhao; F. Gao; Y. Tanikawa; K.Homma; Y. Yamada
    SPIE Proceedings, 掲載ページ 5138-11, 出版日 2003年01月, 査読付
    研究論文(国際会議プロシーディングス), 英語
  • Fundamental Study of Reflection Pulse Oximetry
    Keisuke Matsushita; Kazuo Aoki; Naoto Kakuta; Yukio Yamada
    Optical Review, Optical Society of Japan, 10巻, 5号, 掲載ページ 482-487, 出版日 2003年, 査読付, For the purpose of developing reflection pulse oximetry, we have analyzed the light propagation in tissue to calculate the photon-visit depth for reflected light and to estimate the measured intensities of transmitted and reflected light using the analytical solutions of the photon diffusion equation. The effects of the reflectance of the probe surface have been studied, and a low reflecting surface has been found to provide deeper photon-visit depth than a high reflecting surface for reflection pulse oximetry. Based on analytical estimation, we made reflection type probes, and conducted preliminary experiments to confirm the feasibility of this type of pulse oximetry.
    研究論文(国際会議プロシーディングス), 英語
  • Monte Carlo Simulation of Near Infrared Reflectance Spectroscopy in the Wavelength Range from 1000 nm to 1900 nm
    Kenji Iino; Katsuhiko Maruo; Hidenobu Arimoto; Koji Hyodo; Tetsu Nakatani; Yukio Yamada
    Optical Review, Optical Society of Japan, 10巻, 6号, 掲載ページ 600-606, 出版日 2003年, 査読付, We have calculated the characteristics of reflected near infrared light, which is incident on the skin surface, scattered in the skin tissue and detected, in the wavelength range from 1000 nm to 1900 nm. We have used a Monte Carlo method to calculate the propagation path, the average photon visit depth, the average photon path length, etc. for the cases of short source-detector distances, to which the Isotropic scattering approximation cannot be applied. An experiment to validate the simulation results was also conducted using a liquid phantom.
    研究論文(国際会議プロシーディングス), 英語
  • Photon migration in biological tissue and application to diffuse optical tomography
    Yukio Yamada; Feng Gao; Huijuan Zhao; Yukari Tanikawa; Kazuhiro Homma
    Pacific Rim Conference on Lasers and Electro-Optics, CLEO - Technical Digest, Institute of Electrical and Electronics Engineers Inc., 2巻, 掲載ページ 463, 出版日 2003年, 査読付, Near-infrared photon migration in biological tissue is dominated by strong scattering compared with absorption and modeled as a diffusion phenomenon. The modeling of photon migration in tissue is introduced and its application to diffuse optical imaging is explained.
    研究論文(国際会議プロシーディングス), 英語
  • Anatomical and functional images of in vitro and in vivo tissues by NIR time-domain diffuse optical tomography
    HJ Zhao; F Gao; Y Tanikawa; K Homma; Y Onodera; Y Yamada
    JSME INTERNATIONAL JOURNAL SERIES C-MECHANICAL SYSTEMS MACHINE ELEMENTS AND MANUFACTURING, JAPAN SOC MECHANICAL ENGINEERS, 45巻, 4号, 掲載ページ 1033-1039, 出版日 2002年12月, 査読付, Near infra-red (NIR) diffuse optical tomography (DOT) has gained much attention and it will be clinically applied to imaging breast, neonatal head, and the hemodynamics of the brain because of its noninvasiveness and deep penetration in biological tissue. Prior to achieving the imaging of infant brain using DOT, the developed methodologies need to be experimentally justified by imaging some real organs with simpler structures. Here we report our results of an in vitro chicken leg and an in vivo exercising human. forearm from the data measured by a multi-channel. time-resolved NIR system. Tomographic images were reconstructed by a two-dimensional image reconstruction algorithm based on a modified generalized pulse spectrum technique for simultaneous reconstruction of the mu(alpha) and mu(s)'. The absolute mu(alpha)(-) and mu(s)' -images revealed the inner structures of the chicken leg and the forearm, where the. bones were clearly distinguished from the muscle. The Deltamu(alpha)-images showed the blood volume changes during the forearm exercise, proving that the system and the image reconstruction algorithm could potentially be used for imaging not only the anatomic structure but also the hemodynamics in neonatal heads.
    研究論文(学術雑誌), 英語
  • LIGHT PROPAGATION IN BIOLOGICAL TISSUES AND OPTICAL DIAGNOSTICS BY IMAGING AND SPECTROSCOPY
    Yukio Yamada
    掲載ページ 1-2, 出版日 2002年12月, 査読付
    研究論文(国際会議プロシーディングス), 英語
  • Semi-three-dimensional algorithm for time-resolved diffuse optical tomography by use of the generalized pulse spectrum technique
    F. Gao; Y. Tanikawa; H. Zhao; Y. Yamada
    Applied Optics, 41巻, 34号, 掲載ページ 7346-7358, 出版日 2002年11月, 査読付
    研究論文(学術雑誌), 英語
  • 透過型時間分解法による生体組織の光学特性測定
    田中健之; 谷川ゆかり; 荒木隆一郎; 山田幸生; 岡田英史
    光学, 31巻, 12号, 掲載ページ 886-892, 出版日 2002年11月, 査読付
    研究論文(学術雑誌), 日本語
  • Monte Carlo simulation of NIR reflectance spectroscopy in the wavelength range from 1000nm to 1900nm
    Kenji IINO; Katsuhiko MARUO; Yukio YAMADA
    Asian Symposium of Biomedical Optics and Photomedicine (BOPM 2002), 掲載ページ 232-233, 出版日 2002年10月, 査読付
    研究論文(その他学術会議資料等), 英語
  • Analysis of light propagation in strongly scattering media, and its application to optical topography
    Takeshi SUZUKI; Tsuyoshi YAMAMOTO; Yukio YAMADA
    Asian Symposium of Biomedical Optics and Photomedicine (BOPM 2002),, 掲載ページ 102-103, 出版日 2002年10月, 査読付
    研究論文(国際会議プロシーディングス), 英語
  • Fundamental study of reflection pulse oximetry
    Keisuke MATSUSHITA; Kazuo AOKI; Yukio YAMADA
    Asian Symposium of Biomedical Optics and Photomedicine (BOPM 2002),, 掲載ページ 188-189, 出版日 2002年10月, 査読付
    研究論文(国際会議プロシーディングス), 英語
  • Arranging optical fibres for the spatial resolution improvement of topographical images
    T Yamamoto; A Maki; T Kadoya; Y Tanikawa; Y Yamada; E Okada; H Koizumi
    PHYSICS IN MEDICINE AND BIOLOGY, IOP PUBLISHING LTD, 47巻, 18号, 掲載ページ 3429-3440, 出版日 2002年09月, 査読付, Optical topography is a method for visualization of cortical activity. Ways of improving the spatial resolution of the topographical image with three arrangements of optical fibres are discussed. A distribution of sensitivity is obtained from the phantom experiment, and used to reconstruct topographical images of an activation area of the brain with the fibres in each arrangement. The correlations between the activated area and the corresponding topographical images are obtained, and the effective arrangement of the optical fibres for improved resolution is discussed.
    研究論文(学術雑誌), 英語
  • 組織酸素飽和度計測用光プローブ付き脳へらの開発
    小野寺陽一; 山田幸生; 酒谷 薫; 堀 智勝
    医用電子と生体工学, 40巻, 3号, 掲載ページ 157-164, 出版日 2002年07月, 査読付
    研究論文(学術雑誌), 日本語
  • Optical imaging using time-resolved measurements
    Y. Yamada; F. Gao; H. Zhao; Y. Tanikawa; Y. Onodera; A. Sassaroli
    PIERS (Progress In Electromagnetics Research Symposium) 2002, 出版日 2002年07月
    研究論文(国際会議プロシーディングス), 英語
  • Optical Topography --- Visualization of Brain Activation by Near-Infrared Spectroscopy
    T. Yamamoto; A. Maki; Y. Tanikawa; M. Kiguchi; E. Okada; Y. Yamada; H. Koizumi
    PIERS (Progress In Electromagnetics Research Symposium) 2002, 出版日 2002年07月
    研究論文(国際会議プロシーディングス), 英語
  • Imaging of in vitro chicken leg using time-resolved near-infrared optical tomography
    HJ Zhao; F Gao; Y Tanikawa; Y Onodera; M Ohmi; M Haruna; Y Yamada
    PHYSICS IN MEDICINE AND BIOLOGY, IOP PUBLISHING LTD, 47巻, 11号, 掲載ページ 1979-1993, 出版日 2002年06月, 査読付, Near-infrared optical imaging gains much attention because of its noninvasiveness and deep penetration depths into tissue. Here, we report near-infrared optical tomographic imaging of an in vitro chicken leg from time-resolved measurements. The in vitro chicken leg, dipped in a cylindrical container filled with diluted Intralipid-10% solution, was imaged with a multi-channel time-resolved imaging system. A two-dimensional reconstruction algorithm based on a modified generalized pulse spectrum technique has been developed to reconstruct the images of both the absorption and reduced scattering coefficients simultaneously and quickly. The results demonstrate that a simultaneous reconstruction of absorption and reduced scattering coefficients from time-resolved measurement has a potential to reveal the changes in the optical properties associated with not only the physiological information but also the anatomical structure of the organ.
    研究論文(学術雑誌), 英語
  • Maps of optical differential pathlength factor of human adult forehead, somatosensory motor and occipital regions at multi-wavelengths in NIR
    HJ Zhao; Y Tanikawa; F Gao; Y Onodera; A Sassaroli; K Tanaka; Y Yamada
    PHYSICS IN MEDICINE AND BIOLOGY, IOP PUBLISHING LTD, 47巻, 12号, 掲載ページ 2075-2093, 出版日 2002年06月, 査読付, The optical differential pathlength factor (DPF) is an important parameter for physiological measurement using near infrared spectroscopy, but for the human adult head it has been available only for the forehead. Here we report measured DPF results for the forehead, somatosensory motor and occipital regions from measurements on 11 adult volunteers using a time-resolved optical imaging system. The optode separation was about 30 mm and the wavelengths used were 759 rim, 799 nm and 834 nm. Measured DPFs were 7.25 for the central forehead and 6.25 for the temple region at 799 nm. For the central somatosensory and occipital areas (10 mm above the inion), DPFs at 799 nm are 7.5 and 8.75, respectively. Less than 10%, decreases of DPF for all these regions were observed when the wavelength increased from 759 nm to 834 nm. To compare these DPF maps with the anatomical structure of the head, a Monte Carlo simulation was carried out to calculate DPF for these regions by using a two-layered semi-infinite model and assuming the thickness of the upper layer to be the sum of the thicknesses of scalp and skull, which was measured from MRI images of a subject's head. The DPF data will be useful for quantitative C, monitoring of the haemodynamic changes occurring in adult heads.
    研究論文(学術雑誌), 英語
  • Photochemical and photothermal model for pulsed-laser ablation
    M Sadoqi; S Kumar; Y Yamada
    JOURNAL OF THERMOPHYSICS AND HEAT TRANSFER, AMER INST AERONAUT ASTRONAUT, 16巻, 2号, 掲載ページ 193-199, 出版日 2002年04月, 査読付, A model of the interaction of UV laser pulses with organic polymers is presented. The three distinct features of this model are as follows: 1) It combines photochemical and photothermal processes for breaking bonds. 2) It tracks the percentage of bonds broken where the higher dissociative states are not allowed to relax back to the lower states. 3) The model does not need an experimentally inferred value of threshold fluence to determine the onset of ablation. The mathematical model presented here is based on the system of a two-photon absorption model, where sets of rate equations that include radiative transport and energy absorption are solved. Solutions of this model are discussed, and the results are shown to compare well with experimental etch depth vs fluence curves from the literature for a wide range of pulse widths from 7 to 300 ns. Parametric results are also presented for 193- and 308-nm UV laser wavelengths for different laser and polymer parameters. The dependence of the temperatures and ablation depths for different laser fluences and widths of the laser pulses are obtained.
    研究論文(学術雑誌), 英語
  • Analysis of multi-spectral reflectance of exposed brain tissue
    K. Yokoyama; K. Honjo; M. Watanabe; E. Okada; A. Maki; Y. Yamada; H. Iseki
    Advances in Optical Imaging and Photon Migration (AOIPM), Opt. Soc. Am., 出版日 2002年04月
    研究論文(国際会議プロシーディングス), 英語
  • Improvement of image quality in diffuse optical tomography by use of full time-resolved data
    Feng Gao; Huijuan Zhao; Yukio Yamada
    Applied Optics, Optical Society of America (OSA), 41巻, 4号, 掲載ページ 778-791, 出版日 2002年02月01日, 査読付, In the field of diffuse optical tomography (DOT), it is widely accepted that time-resolved (TR) measurement can provide the richest information on photon migration in a turbid medium, such as biological tissue. However, the currently available image reconstruction algorithms for TR DOT are based mostly on the cw component or some featured data types of original temporal profiles, which are related to the solution of a time-independent diffusion equation. Although this methodology can greatly simplify the reconstruction process, it suffers from low spatial resolution and poor quantitativeness owing to the limitation of effectively applicable data types. To improve image quality, it has been argued that exploiting the full TR data is essential. We propose implementation of a DOT algorithm by using full TR data and furthermore a variant algorithm with time slices of TR data to alleviate the computational complexity and enhance noise robustness. Compared with those algorithms where the featured data types are used, our evaluations on the spatial resolution and quantitativeness show that a significant improvement in imaging quality can be achieved when full TR data are used, which convinces the DOT community of the potential advantage of the TR domain over cw and frequency domains. © 2002 Optical Society of America.
    研究論文(学術雑誌), 英語
  • Improvement of image quality in diffuse optical tomography by use of full time-resolved data
    F Gao; HJ Zhao; Y Yamada
    APPLIED OPTICS, OPTICAL SOC AMER, 41巻, 4号, 掲載ページ 778-791, 出版日 2002年02月, 査読付, In the field of diffuse optical tomography (DOT), it is widely accepted that time-resolved (TR) measurement can provide the richest information on photon migration in a turbid medium, such as biological tissue. However, the currently available image reconstruction algorithms for TR DOT are based mostly on the cw component or some featured data types of original temporal profiles, which are related to the solution of a time-independent diffusion equation. Although this methodology can greatly simplify the reconstruction process, it suffers from low spatial resolution and poor quantitativeness owing to the limitation of effectively applicable data types. To improve image quality, it has been argued that exploiting the full TR data is essential. We propose implementation of a DOT algorithm by using full TR data and furthermore a variant algorithm with time slices of TR data to alleviate the computational complexity and enhance noise robustness. Compared with those algorithms where the featured data types are used, our evaluations on the spatial resolution and quantitativeness show that a significant improvement in imaging quality can be achieved when full TR data are used, which convinces the DOT community of the potential advantage of the TR domain over cw and frequency domains. (C) 2002 Optical Society of America.
    研究論文(学術雑誌), 英語
  • C221 時間分解型光 CT による生体の解剖学的および生理学的イメージング
    趙 会娟; 高 峰; 谷川 ゆかり; 本間 一弘; 小野寺 陽一; 山田 幸生
    熱工学講演会講演論文集, 一般社団法人日本機械学会, 2002巻, 掲載ページ 381-382, 出版日 2002年, Near infra-red (NIR) diffuse optical tomography (DOT) has gained much attention for recent years because it is noninvasive and deeply penetrating to biologic tissue. Here we report our reconstruction results of an in vitro chicken leg and an in vivo exercising human forearm using a multi-channel time-resolved NIR system and a two-dimensional image reconstruction algorithm based on a modified generalized pulse spectrum technique for simultaneous reconstruction of the absorption and scattering coefficients. The images revealed the anatomies of a chicken leg and a human forearm, and the bones were clearly distinguished from the muscle. The absorption images showed the blood volume changes during the forearm exercise, proving that the system and the algorithm could potentially be used for imaging not only the anatomy but also the hemodynamics in living tissues.
    日本語
  • 205 インスリンポンプ用熱式超微量流量計の基礎研究
    西山 尚; 小西 義昭; 藤原 真人; 直野 義昭; 角田 直人; 山田 幸生
    年次大会講演論文集, 一般社団法人日本機械学会, 2002巻, 掲載ページ 17-18, 出版日 2002年, The flow rate of insulin from insulin pumps for diabetic patients is less than 3.0 μl/min, and the average flow velocity in a tube with a diameter of 0.4 mm becomes less than 0.4 mm/s resulting in the maximum Reynolds number of about 0.2. A thermo-trace type flow meter is employed for a low meter in this very small range of flow rate and velocity. A theoretical analysis and preliminary experiment were conducted for the flow meter. It was found that the influence of heat conduction in the direction of the tube axis must be included which is usually ignored in the boundary flow analyses.
    日本語
  • Analytical approximate solutions of the time-domain diffusion equation in layered slabs
    F Martelli; A Sassaroli; Y Yamada; G Zaccanti
    JOURNAL OF THE OPTICAL SOCIETY OF AMERICA A-OPTICS IMAGE SCIENCE AND VISION, OPTICAL SOC AMER, 19巻, 1号, 掲載ページ 71-80, 出版日 2002年01月, 査読付, Time-domain analytical solutions of the diffusion equation for photon migration through highly scattering two- and three-layered slabs have been obtained. The effect of the refractive-index mismatch with the external medium is taken into account, and approximate boundary conditions at the interface between the diffusive layers have been considered. A Monte Carlo code for photon migration through a layered slab has also been developed. Comparisons with the results of Monte Carlo simulations showed that the analytical solutions correctly describe the mean path length followed by photons inside each diffusive layer and the shape of the temporal profile of received photons, while discrepancies are observed for the continuous-wave reflectance or transmittance. (C) 2002 Optical Society of America.
    研究論文(学術雑誌), 英語
  • Time-resolved diffuse optical tomography using a modified generalized pulse spectrum technique
    F Gao; HJ Zhao; Y Tanikawa; Y Yamada
    IEICE TRANSACTIONS ON INFORMATION AND SYSTEMS, IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG, E85D巻, 1号, 掲載ページ 133-142, 出版日 2002年01月, 査読付, Generalized Pulse Spectrum Technique (GPST) is a method to solve the inverse problems of wave-propagation and diffusion-dominated phenomena, and therefore has been popularly applied in image reconstruction of time-resolved diffuse optical tomography. With a standard GPST for simultaneous re construction of absorption and scattering coefficients, the products of the gradients of the Green's function and the photon-density flux, based on the photon-diffusion equation, are required to calculate the diffusion-related Jacobian matrix. The adversities are of two-folds: time-consuming and singular in the field near the source. The latter causes a severe insensitivity of the algorithm to the scattering changes deep inside tissue. To cope with the above difficulties, we propose(,. in this paper a modified GPST algorithm that only involves the Green's function and the photon-density flux themselves in the scattering-related matrix. Our simulated and experimental reconstruct ions show that the modified algorithm can significantly improve the quality of scattering image and accelerate the reconstruction process, without an evident degradation in absorption image.
    研究論文(学術雑誌), 英語
  • Experimental and numerical study of the colour appearance of tattoo models
    M. Shimada; J. Hata; Y. Yamada; M. Itoh; A. Uchida; T. Yatagai
    Medical and Biological Engineering and Computing, Peter Peregrinus Ltd, 40巻, 2号, 掲載ページ 218-224, 出版日 2002年, 査読付, The colour of tattooed skin has been predicted by a Monte Carlo method based on the optical coefficient spectra of the skin and tattoo dyes. Slices of pig skin, a tattoo phantom and skin phantoms with different thickness were prepared, and their reflectance and transmittance spectra were measured using an integrating sphere at wavelengths varying from 400 nm to 700 nm. The absorption and scattering coefficient spectra of skin phantoms, pig skins and the tattoo phantom were each calculated using the inverse Monte Carlo method. The skin phantoms and pig skins were overlaid on the tattoo phantom, and the reflectance spectra of the two-layered structures were measured. The reflectance spectra of the two-layered structures were calculated from the optical coefficient spectra using the Monte Carlo method. They agreed well with the measured spectra. The colour differences between the calculated and measured spectra were also evaluated by the L*a*b* colour space distances and showed good agreement, with 3.49 for the skin phantoms and 8.27 for the pig skins.
    研究論文(学術雑誌), 英語
  • Melanin and blood concentration in human skin studied by multiple regression analysis: experiments
    M Shimada; Y Yamada; M Itoh; T Yatagai
    PHYSICS IN MEDICINE AND BIOLOGY, IOP PUBLISHING LTD, 46巻, 9号, 掲載ページ 2385-2395, 出版日 2001年09月, 査読付, Knowledge of the mechanism of human skin colour and measurement of melanin and blood concentration in human skin are needed in the medical and cosmetic fields. The absorbance spectrum from reflectance at the visible wavelength of human skin increases under several conditions such as a sunburn or scalding. The change of the absorbance spectrum from reflectance including the scattering effect does not correspond to the molar absorption spectrum of melanin and blood. The modified Beer-Lambert law is applied to the change in the absorbance spectrum from reflectance of human skin as the change in melanin and blood is assumed to be small. The concentration of melanin and blood was estimated from the absorbance spectrum reflectance of human skin using multiple regression analysis. Estimated concentrations were compared with the measured one in a phantom experiment and this method was applied to in vivo skin.
    研究論文(学術雑誌), 英語
  • Melanin and blood concentration in a human skin model studied by multiple regression analysis: assessment by Monte Carlo simulation
    M Shimada; Y Yamada; M Itoh; T Yatagai
    PHYSICS IN MEDICINE AND BIOLOGY, IOP PUBLISHING LTD, 46巻, 9号, 掲載ページ 2397-2406, 出版日 2001年09月, 査読付, Measurement of melanin and blood concentration in human skin is needed in the medical and the cosmetic fields because human skin colour is mainly determined by the colours of melanin and blood. It is difficult to measure these concentrations in human skin because skin has a multi-layered structure and scatters light strongly throughout the visible spectrum. The Monte Carlo simulation currently used for the analysis of skin colour requires long calculation times and knowledge of the specific optical properties of each skin layer. A regression analysis based on the modified Beer-Lambert law is presented as a method of measuring melanin and blood concentration in human skin in a shorter period of time and with fewer calculations. The accuracy of this method is assessed using Monte Carlo simulations.
    研究論文(学術雑誌), 英語
  • Biomedical optical imaging by a time-resolved multichannel system
    Y. Yamada
    Joint Symposium on Bio-Sensing and Bio-Imaging, Yamagata, Japan, August 2-4, 2001, 出版日 2001年08月
    研究論文(国際会議プロシーディングス), 英語
  • 計測用プローブの高密度配置によるトポグラフィック画像の画質改善
    山本剛; 牧敦; 角谷卓磨; 谷川ゆかり; 岡田英史; 山田幸生
    日本光学会 第2回生体医用光学研究会講演論文集, 出版日 2001年07月
    研究論文(研究会,シンポジウム資料等), 日本語
  • Development of a retractor with the capability of oxygenation monitoring
    Y. Onodera; Y. Yamada; K. Sakatani; T. Hori
    PIERS (Progress in Electromagnetic Research Symposium) 2000, Osaka, Japan, July 18-22, 2001, 出版日 2001年07月, 査読付
    研究論文(国際会議プロシーディングス), 英語
  • 反射型時間分解法による小体積試料の光学特性測定
    田中健之; 荒木隆一郎; Angelo Sassaroli; 山田幸生; 岡田英史
    第40回日本ME学会大会 医用電子と生体工学, 出版日 2001年05月
    研究論文(研究会,シンポジウム資料等), 日本語
  • Performance of fitting procedures in curved geometry for retrieval of the optical properties of tissue from time-resolved measurements
    A Sassaroli; F Martelli; G Zaccanti; Y Yamada
    APPLIED OPTICS, OPTICAL SOC AMER, 40巻, 1号, 掲載ページ 185-197, 出版日 2001年01月, 査読付, By use of the solution of the diffusion equation for cylindrical and spherical geometry, two fitting procedures for retrieval of the optical properties from time-resolved measurements have been implemented. The fitting procedures are based on the Levenberg-Marquardt algorithm, in which the fitting parameters are the absorption coefficient, the reduced scattering coefficient, and an amplitude factor. Monte Carlo data generated for cylindrical and spherical geometry were fitted by these fitting procedures, and the retrieved optical properties were compared with those obtained from the inversion procedure with a mismatched geometry of a semi-infinite medium. The effects of refractive-index mismatch and of different boundary conditions of the diffusion equation were also studied, together with the effects of several sources of error that are typically found in time-resolved measurements. The advantages and drawbacks of these fitting procedures, including many details in several situations of interest in the field of tissue optics, are discussed. The results also offer a guideline to understanding the effects of mismatching in curved geometry as functions of source-detector distance and radii of cylinders or spheres. (C) 2001 Optical Society of America OCIS codes: 170.3660, 170.5280, 170.7050.
    研究論文(学術雑誌), 英語
  • Image reconstruction from experimental measurements of an multichannel time-resolved optical tomographic imaging system
    F Gao; H Zhao; Y Onodera; A Sassaroli; Y Tanikawa; Y Yamada
    OPTICAL TOMOGRAPHY AND SPECTROSCOPY OF TISSUE IV, SPIE-INT SOC OPTICAL ENGINEERING, 4250巻, 掲載ページ 351-361, 出版日 2001年, 査読付, An optical tomographic imaging system that is composed of 32 near infrared time-resolved spectroscopic channels has been newly implemented for the experimental evaluation of diffuse optical imaging schemes. This article reports on some initial results reconstructed from the transmitted measurement of such a time-resolved system. Two cylindrical tissue-like phantoms having two- and three-dimensional interior structures respectively are employed for the validation of the reconstruction algorithm, which uses the diffusion-based photon migration model and an optimization-based reconstruction solver. We compare the performances of the proposed two- and semi three-dimensional algorithms in reconstructing two-dimensional phantom and demonstrate the ability of full three-dimensional algorithm to simultaneously image multiple slices of there-dimensional phantom, using absolute and/or differential imaging schemes. Also addressed are some technical issues on the calibrations of the time-resolved measurements for matching the photon migration model and alleviating the influence of the inconsistency of the detecting channels. Our reconstructions show that the image quality can be significantly improved by differential imaging scheme that takes radio or difference of the real and reference measurement as the data type. Moreover, the results demonstrate the feasibility of experimental reconstruction from absolute mean time of flight of the temporal measurement, and argue that finer adjustments for the consistency of the detecting channels are necessary to improve the image quality of the absolute reconstruction.
    研究論文(国際会議プロシーディングス), 英語
  • 3D simultaneous reconstruction of absorption and scattering coefficients in time-resolved optical tomography
    F Gao; P Poulet; Y Yamada
    OPTICAL TOMOGRAPHY AND SPECTROSCOPY OF TISSUE IV, SPIE-INT SOC OPTICAL ENGINEERING, 4250巻, 掲載ページ 514-521, 出版日 2001年, 査読付, A Newton-Raphson inversion algorithm is extended for simultaneous absorption and scattering reconstruction of full 3-dimensional (3D) time-resolved diffuse optical tomography, which is based on efficient computation of Jacobian matrix of the forward model, and uses Algebraic Reconstruction Technique as the linear inversion tool. We validate the algorithm using both numerically simulated data from 3D finite-element discretization model of a tissue-like cylindrical phantom, embedding three inhomogeneities with different geometric and optical properties, as well as experimental measurements for a 3-D structural cylindrical phantom containing three absorptive rods, by means of fan-beam scanning mode. Our results show that a full 3D simultaneous reconstruction of absorption and scattering in turbid medium can be achieved with highly reasonable quality provided that the diffusive nature of light propagation in tissue is appropriately modeled, and temporal information of the measurements effectively employed.
    研究論文(国際会議プロシーディングス), 英語
  • Method to measure the diffusion coefficient of a layered medium
    F Martelli; A Sassaroli; Y Yamada; G Zaccanti
    OPTICAL TOMOGRAPHY AND SPECTROSCOPY OF TISSUE IV, SPIE-INT SOC OPTICAL ENGINEERING, 4250巻, 掲載ページ 101-108, 出版日 2001年, 査読付, A method to measure the diffusion coefficient of homogeneous and layered media, based on multi-distance measurements of time-resolved reflectance is proposed. The diffusion coefficient is retrieved by fitting procedures on the logarithm of the ratio of two reflectances measured at two different source-receiver distances. The inversion procedure uses analytical models derived from the diffusion equation and it is not affected by the boundary conditions used. For layered media the inversion procedure retrieves the diffusion coefficient of the first layer. The proposed procedure is simpler than others usually employed and also provides a reliable criterion for retrieval of information on the layered structure of the diffusive medium.
    研究論文(国際会議プロシーディングス), 英語
  • Measuring of optical properties of small volume samples using time-resolved reflectance spectroscopy.
    K Tanaka; R Araki; Y Yamada; E Okada
    OPTICAL TOMOGRAPHY AND SPECTROSCOPY OF TISSUE IV, SPIE-INT SOC OPTICAL ENGINEERING, 4250巻, 掲載ページ 282-289, 出版日 2001年, 査読付, Measurements of optical properties of biological tissues are necessary to develop optical diagnostic instruments. Although various methods to measure the optical properties of biological tissue have been proposed, very few measurements have been carried out in vivo because of their difficulties. We are developing a new method to obtain the optical properties in vivo using time-resolved measurement system. This new method determines the optical properties by comparing the experimental results of time-resolved measurement with the results of a series of Monte Carlo simulation using known optical properties. By combining results of a Monte Carlo simulation with the time-resolved reflectance measurement for the case of small source-detector distance, it is possible to measure the optical properties of small samples in vivo to which the diffusion approximation can't be applied. However, the optical properties obtained from the time-resoIved reflectance method at small source-detector distances do not agree with the results from the integrating sphere system. The time-resolved reflectance at small source-detector distance should be influenced by the scattering phase function of the tissue. We discuss the effects of the phase function on the measurement of the optical properties obtained from time-resolved reflectance method.
    研究論文(国際会議プロシーディングス), 英語
  • Noninvasive brain-function measurement system: Optical topography
    T Yamamoto; A Maki; Y Yamashita; Y Tanikawa; Y Yamada; H Koizumi
    OPTICAL TOMOGRAPHY AND SPECTROSCOPY OF TISSUE IV, SPIE-INT SOC OPTICAL ENGINEERING, 4250巻, 掲載ページ 339-350, 出版日 2001年, 査読付, Authors proposed optical topography to visualize the blood-volume change in the cortex associated with brain activation. The diffusion equation was used to obtain the sensitivity distribution of the blood-volume change. We show that the sensitivity distribution agrees with that obtained by the Monte-Carlo simulation. We then developed a phantom that simulates the light scattering property and brain activation in the cortex. Topographic images of the absorber in the phantom are obtained, and high location accuracy but spatial resolution of the topographic image were found. In addition, we derived a methodology to arrange optodes at high density in order to improve the spatial resolution of the topographic image.
    研究論文(国際会議プロシーディングス), 英語
  • Photon migration in biological tissues, their optical properties and imaging
    Y Yamada; A Sassaroli; F Martelli; F Gao; HJ Zhao; Y Onodera; Y Tanikawa; K Tanaka; R Araki
    CLEO(R)/PACIFIC RIM 2001, VOL I, TECHNICAL DIGEST, IEEE, 掲載ページ 368-369, 出版日 2001年, This paper reviews the phenomenon of photon migration in biological tissues which strongly scatter and weakly absorb light in the near infrared wavelength range. The optical properties of tissues are given, and the methods of obtaining optical tomographic images are introduced.
    研究論文(国際会議プロシーディングス), 英語
  • Light propagation in adult heads obtained from a time-resolved NIR optical imaging system
    H Zhao; Y Onodera; Y Tanikawa; F Gao; A Sassaroli; K Tanaka; Y Yamada
    CLEO(R)/PACIFIC RIM 2001, VOL I, TECHNICAL DIGEST, IEEE, 掲載ページ 362-363, 出版日 2001年, 査読付, We discussed the influence of optical properties on light propagation in terms of the results of time-resolved NIR brain function experiment using adult heads. The results show that CSF (cerebrospinal fluid) does have some scattering and absorption; the change in the absorption coefficient influences not only the falling part of temporal profile but also the rising part.
    研究論文(国際会議プロシーディングス), 英語
  • Photon migration in biological tissues, their optical properties and imaging
    Y Yamada; A Sassaroli; F Martelli; F Gao; HJ Zhao; Y Onodera; Y Tanikawa; K Tanaka; R Araki
    CLEO(R)/PACIFIC RIM 2001, VOL I, TECHNICAL DIGEST, IEEE, 掲載ページ 368-369, 出版日 2001年, This paper reviews the phenomenon of photon migration in biological tissues which strongly scatter and weakly absorb light in the near infrared wavelength range. The optical properties of tissues are given, and the methods of obtaining optical tomographic images are introduced.
    研究論文(国際会議プロシーディングス), 英語
  • Measurement of optical properties of brain in vivo
    Y. Yamada; A. Sassaroli; Y. Tanikawa; F. Martelli; R. Arakai; K. Tanaka
    Pacifichem 2000, Symposium No. 75, Frontiers of Spectroscopic Analysis of the Brain, Honolulu, USA, (Dec. 14-15, 2000), 出版日 2000年12月
    研究論文(国際会議プロシーディングス), 英語
  • Simultaneous mapping of absorption and scattering coefficients from a three-dimensional model of time-resolved optical tomography
    F Gao; P Poulet; Y Yamada
    APPLIED OPTICS, OPTICAL SOC AMER, 39巻, 31号, 掲載ページ 5898-5910, 出版日 2000年11月, 査読付, A Newton-Raphson inversion algorithm has been extended for simultaneous absorption and scattering reconstruction of fully three-dimensional (3D) diffuse optical tomographic imaging from time-resolved measurements. The proposed algorithm is derived from the efficient computation of the Jacobian matrix of the forward model and uses either the algebraic reconstruction technique or truncated singular-value decomposition as the linear inversion tool. Its validation was examined with numerically simulated data from 3-D finite-element discretization models of tissuelike phantoms, with several combinations of geometric and optical properties, as well as two commonly used source-detector configurations. Our results show that the fully 3-D image reconstruction of an object can be achieved with reasonable quality when volumetric light propagation in tissues is considered, and temporal information from the measurements can be effectively employed. Also, we investigated the conditions under which 3-D issues could be approximately addressed with two-dimensional reconstruction algorithms and further demonstrated that these conditions are seldom predictable or attainable in practice. Thus the application of 3-D algorithms to realistic situations is necessary. (C) 2000 Optical Society of America OCIS codes: 170.6920, 170.3010, 100.3190.
    研究論文(学術雑誌), 英語
  • Method for measuring the diffusion coefficient of homogeneous and layered media
    F Martelli; A Sassaroli; Y Yamada; G Zaccanti
    OPTICS LETTERS, OPTICAL SOC AMER, 25巻, 20号, 掲載ページ 1508-1510, 出版日 2000年10月, 査読付, A method for measuring the diffusion coefficient of homogeneous and layered media, based on multidistance measurements of time-resolved reflectance, is proposed. The diffusion coefficient is retrieved from the logarithm between two measurements of reflectance at two different distances. The proposed procedure is simpler than others usually employed and also provides a reliable criterion for retrieval of information on the layered structure of a diffusive medium. (C) 2000 Optical Society of America OCIS codes: 170.9660, 170.5280, 170.4580, 170.6980, 170.7050.
    研究論文(学術雑誌), 英語
  • 皮膚下における色素の見え方の変化
    島田美帆; 畑寿太郎; 山田幸生; 伊藤雅英; 内田彰子; 谷田貝豊彦
    光学, 29巻, 6号, 掲載ページ 392-398, 出版日 2000年06月, 査読付
    研究論文(学術雑誌), 日本語
  • Fabrication of dynamic human head phantom and time-resolved measurement
    Y. Tanikawa; D. Imai; K. Tanaka; H. Kawamura; Y. Yamada
    Proceedings of the 8th International Conference on Rapid Prototyping, Tokyo (June 12-13, 2000), 掲載ページ 296-301, 出版日 2000年06月
    研究論文(国際会議プロシーディングス), 英語
  • 1315 豚頭部の光学特性測定
    SASSAROLI Angelo; 谷川 ゆかり; MARTELLI Fabrizio; 荒木 隆一郎; 田中 健之; 山田 幸生
    年次大会講演論文集, 一般社団法人日本機械学会, 2000巻, 掲載ページ 335-336, 出版日 2000年
    英語
  • Explanation of human skin color by multiple linear regression analysis based on the modified Lambert-Beer law
    Miho Shimada; Yuji Masuda; Yukio Yamada; Masahide Itoh; Motoji Takahashi; Toyohiko Yatagai
    Optical Review, Optical Society of Japan, 7巻, 4号, 掲載ページ 348-352, 出版日 2000年, 査読付, Quantitative analysis of human skin color is needed in the medical and cosmetic fields. Because of the strong light scattering by biological tissues, however, analysis of skin color has not yet been fully successful. Human skin color is dominated by the colors of blood and melanin which are modified by scattering. Exposure of human skin to hot water or UV-ray changes its color because the absorbance spectrum of reflection from the human skin, and the changes in the absorbance spectra of reflection reflect the absorbance spectra of blood and melanin which are the absorption spectrum distorted by scattering. By applying the modified Lambert-Beer law, the absorbance spectrum of reflection from human skin can be expressed proportional to those distorted absorbance spectra of blood and melanin. Multiple linear regression analysis is successfully used to reproduce the absorbance spectrum of reflection from human skin from the distorted absorbance spectra of blood and melanin.
    研究論文(学術雑誌), 英語
  • Development and application of noninvasive optical topography
    T Yamamoto; A Maki; Y Yamashita; H Yoshizawa; M Iwata; E Watanabe; Y Tanikawa; Y Yamada; H Koizumi
    OPTICAL SENSING, IMAGING, AND MANIPULATION FOR BIOLOGICAL AND BIOMEDICAL APPLICATIONS, SPIE-INT SOC OPTICAL ENGINEERING, 4082巻, 掲載ページ 24-33, 出版日 2000年, 査読付, Optical topography (OT) is a method for visualizing brain functions noninvasively. In an OT measurement system, near-infrared light, to which living tissue is highly permeable, is irradiated from the scalp of the subject, and the scattered light reflected from the cerebral cortex is detected elsewhere on the scalp. The spatio-temporal. blood volume change in the cortex is visualized based on the signal detected using two-dimensionally arranged optodes. The measurement imposes few constraints on the subject, either physically or mentally, thus the subject is in a natural and relaxed condition during measurement. Here, we describe out OT system, then report on an experiment to evaluate the system using a phantom. We found that OT can accurately locate the activated region in the cortex. Also, as an example of a clinical application of OT, we used our system to measure the language function, demonstrating the system's ability to measure the activity of Broca's area.
    研究論文(国際会議プロシーディングス), 英語
  • Time-resolved measurements of in vivo optical properties of piglet brain
    Angelo Sassaroli; Fabrizio Martelli; Yukari Tanikawa; Kenji Tanaka; Ryuichiro Araki; Yoichi Onodera; Yukio Yamada
    Optical Review, Optical Society of Japan, 7巻, 5号, 掲載ページ 420-425, 出版日 2000年, 査読付, The in vivo optical properties of a piglet brain were measured using a time-resolved system at three different wavelengths (759, 794, 824 nm). To separate the contribution of different head layers to the detected signals, the measurements were acquired from the surfaces of skin, skull, dura mater and brain. The source-detector distance was chosen to assure a mean penetration depth within each layer. Measurements were analyzed and compared with the results of other in vivo measurements reported in literature.
    研究論文(学術雑誌), 英語
  • Performance of a multi-channel time-resolved optical tomographic imaging system and tomographic images
    Y Yamada; M Tamura; H Eda; Oda, I; Y Ito; Y Wada; Y Oikawa; Y Tsunazawa; M Takada; Y Tsuchiya; Y Yamashita; M Oda; A Sassaroli
    PROCEEDINGS OF INTER-INSTITUTE WORKSHOP ON IN VIVO OPTICAL IMAGING AT THE NIH, OPTICAL SOC AMERICA, 掲載ページ 200-204, 出版日 2000年, 査読付, A time-resolved optical imaging system using near-infrared light has been developed and its performance is demonstrated. The system had three pulsed light sources and total 64 channels of detection, working simultaneously for acquisition of the time-resolved data of the pulsed light transmitted through scattering media like biological tissues. The light sources were provided by high power picosecond pulsed diode lasers, and optical switches directed one of the light sources to the object through an optical fiber. The tight signals re-emitted from the surface of the object were collected by optical fibers, and transmitted to a time-resolved detecting system. Each of the detecting channels consisted of an optical attenuator, a fast photomultiplier, and a time-correlated single photon counting circuit which contained a miniaturized constant fraction discriminator / time-to-amplitude converter module, and a signal acquisition unit with an A/D converter. The performance and potentiality of the imaging system have been examined by the image reconstruction from the measured data using solid phantoms containing absorbing rods and blood flow.
    研究論文(国際会議プロシーディングス), 英語
  • Study on the propagation of ultra-short pulse light in cylindrical optical phantoms
    A Sassaroli; F Martelli; D Imai; Y Yamada
    PHYSICS IN MEDICINE AND BIOLOGY, IOP PUBLISHING LTD, 44巻, 11号, 掲載ページ 2747-2763, 出版日 1999年11月, 査読付, A detailed study about ultra-short pulse light propagation inside cylindrical scattering and absorbing phantoms is presented. Some comparisons between a Monte Carlo code and the analytical solution of diffusion equation for a delta(t) source and point-like detectors placed at different angles of detection are shown. To better quantify the agreement between the temporal profiles obtained from the two different methods of calculation, a fitting procedure based on the Levenberg-Marquardt algorithm has been implemented. Some examples on the retrieval of the optical properties for both the Monte Carlo and experimental data are presented. In the case of inhomogeneous cylindrical phantoms, some comparisons between the results of the time-domain 3D model of finite element method and 3D Monte Carlo are also shown.
    研究論文(学術雑誌), 英語
  • Light Propagation in biological Tissue and,Medical ImagingProceedings of Technology for the Next Century---In Celebration of 100 years of Mechanical Engineering at Polytechnic University
    Y. Yamada
    Polytechnic University, (Nov. 4-5, 1999), 出版日 1999年11月
    研究論文(国際会議プロシーディングス), 英語
  • Multichannel time-resolved optical tomographic imaging system
    H Eda; Oda, I; Y Ito; Y Wada; Y Oikawa; Y Tsunazawa; M Takada; Y Tsuchiya; Y Yamashita; M Oda; A Sassaroli; Y Yamada; M Tamura
    REVIEW OF SCIENTIFIC INSTRUMENTS, AMER INST PHYSICS, 70巻, 9号, 掲載ページ 3595-3602, 出版日 1999年09月, 査読付, A time-resolved optical imaging system using near-infrared light has been developed. The system had three pulsed light sources and total 64 channels of detection, working simultaneously for acquisition of the time-resolved data of the pulsed light transmitted through scattering media like biological tissues. The light sources were provided by high power picosecond pulsed diode lasers, and optical switches directed one of the light sources to the object through an optical fiber. The light signals reemitted from the surface of the object were collected by optical fibers, and transmitted to a time-resolved detecting system. Each of the detecting channels consisted of an optical attenuator, a fast photomultiplier, and a time-correlated single photon counting circuit which contained a miniaturized constant fraction discriminator/time-to-amplitude converter module, and a signal acquisition unit with an A/D converter. The performance and potentiality of the imaging system have been examined by the image reconstruction from the measured data using solid phantoms. (C) 1999 American Institute of Physics. [S0034-6748(99)04409-3].
    研究論文(学術雑誌), 英語
  • Measurements of Optical Properties of Biological Tissues Using an Integrating Sphere and Time-resolved Spectroscopy,Advances in Optical Imaging, Photon Migration, and Tissue Optics
    K. Tanaka; R. Araki; Y. Tanikawa; D. Imai; H. Kawamura; Y. Yamada
    Conference on Biomedical Optics, CLEO/Europe and Optical Society of America, Munchen, 掲載ページ 247-249, 出版日 1999年06月, 査読付
    研究論文(国際会議プロシーディングス), 英語
  • Properties of the light emerging from a diffusive medium: angular dependence and flux at the external boundary
    F Martelli; A Sassaroli; G Zaccanti; Y Yamada
    PHYSICS IN MEDICINE AND BIOLOGY, IOP PUBLISHING LTD, 44巻, 5号, 掲載ページ 1257-1275, 出版日 1999年05月, 査読付, By using the diffusion approximation of the radiative transfer equation and the partial-current boundary condition, an analytical expression for the angular dependence of the specific intensity emerging from a diffusive medium has been obtained. The analytical expression for the angular distribution has been validated by comparisons with the results of Monte Carlo simulations. By using the diffusion equation and the extrapolated boundary condition, an heuristic analytical expression for the diffuse time-resolved reflectance has also been obtained by assuming that the photon flux is simply proportional to the fluence rate. For the case of the semi-infinite medium, comparisons with Monte Carlo results are presented and time-resolved reflectance data are fitted with the simple fluence rate formula. The results obtained show that the simple expression correctly describes the time-resolved reflectance giving an error in the retrieved optical parameters smaller than that of other commonly used expressions.
    研究論文(学術雑誌), 英語
  • 零空間補正と最大帰納確率法を用いた光CTの画像再構成
    I. W. Kwee; S. G. Proskurin; 谷川ゆかり; 山田幸生
    日本機械学会論文集,A編, 65巻, 633号, 掲載ページ 982-988, 出版日 1999年05月, 査読付
    研究論文(学術雑誌), 日本語
  • Characteristics of the light transmitted through diffusing media: angular distribution and photon flux at the external boundary
    F Martelli; A Sassaroli; G Zaccanti; Y Yamada
    OPTICAL TOMOGRAPHY AND SPECTROSCOPY OF TISSUE III, PROCEEDINGS OF, SPIE-INT SOC OPTICAL ENGINEERING, 3597巻, 掲載ページ 164-174, 出版日 1999年, 査読付, The characteristics of the light transmitted through diffusing media have been studied by using the diffusion approximation of the radiative transfer equation. Making use of the partial-current-boundary condition an analytical expression for the angular dependence of the specific intensity emerging from a diffusing medium has been obtained. The analytical expression gives results in excellent agreement with Monte Carlo simulations for the slab geometry. The limits of validity of the theory have been investigated.
    Making use of the diffusion equation and of the extrapolated boundary condition, an heuristic analytical expression for the time-resolved reflectance has also been obtained assuming the photon flux as being simply proportional to the fluence rate. The proposed expression is simpler with respect to other commonly used expressions and seems to give better results when used to retrieve the optical properties from time-resolved measurements.
    研究論文(国際会議プロシーディングス), 英語
  • Ultra-short pulse light propagation in cylindrical optical phantoms
    A Sassaroli; F Martelli; Y Yamada; Y Tzunazawa
    OPTICAL TOMOGRAPHY AND SPECTROSCOPY OF TISSUE III, PROCEEDINGS OF, SPIE-INT SOC OPTICAL ENGINEERING, 3597巻, 掲載ページ 146-154, 出版日 1999年, 査読付, Some comparison between the results of 3D FEM and 3D Monte Carlo calculations of light propagation inside highly scattering cylindrical optical phantoms are presented. The temporal profiles of transmitted delta Dirac pulses through the cylindrical phantoms have been calculated for different source-detector angles. The comparisons have been carried out in time-domain and for both homogeneous and inhomogeneous cylindrical phantoms; in the latter case some absorbing cylinders were included inside a scattering cylinder. Refractive index mismatch between the phantoms and the surrounding medium was taken into account. Some comparison with experimental results are also shown.
    研究論文(国際会議プロシーディングス), 英語
  • Analytical solution of the time-dependent photon diffusion equation for a layered medium
    F Martelli; A Sassaroli; Y Yamada
    OPTICAL TOMOGRAPHY AND SPECTROSCOPY OF TISSUE III, PROCEEDINGS OF, SPIE-INT SOC OPTICAL ENGINEERING, 3597巻, 掲載ページ 79-89, 出版日 1999年, 査読付, The scattering and the absorption coefficients of tissue can provide important information about the physiological condition of tissue. Living bodies have a complex structure, therefore in most cases tissue cannot be regarded as a homogeneous medium. In some cases biological tissue have layered structures (head, skin, bone, etc.), consequently in order to measure the optical properties in vivo it is necessary to formulate the photon migration in layered media. Making use of the diffusion equation a theoretical time domain model for photon migration through a highly scattering layered slab has been elaborated. A pencil pulsed light beam is normally incident upon the surface of the first diffusing layer. The effect of the refractive index mismatch with the external medium is taken into account and proper boundary conditions between the diffusing layers are considered. Analytical solutions of the fluence rate inside the layers have been obtained. A Monte Carlo program for the photon migration through a two or a three layered slab has been also developed. The results obtained by using the analytical solution and Monte Carlo simulations are compared and presented. The main goal of this work is the future application of the model on retrieving the optical properties of layered media.
    研究論文(国際会議プロシーディングス), 英語
  • Realistic dynamic brain phantom and time-resolved measurement
    D Imai; K Tanaka; Y Tanikawa-Takahashi; Y Tsunazawa; H Kawamura; Y Yamada
    OPTICAL TOMOGRAPHY AND SPECTROSCOPY OF TISSUE III, PROCEEDINGS OF, SPIE-INT SOC OPTICAL ENGINEERING, 3597巻, 掲載ページ 108-117, 出版日 1999年, 査読付, In the process of developing optical tomographic imaging systems for diagnosis of disease and study of brain functions of human heads, we need realistic optical phantoms which anatomically and optically simulate human heads with complicated and multi-layered structures. Previously we have reported design and fabrication methods of optical head phantoms based on MRI images of a human head. The phantoms were simulated the multilayered structure with different optical properties at five layers; i.e., skin, skull, cerebrospinal fluid layer, gray matter and white matter. Also the phantoms which were mainly made of solid resin had dynamic parts to simulate the temporal variation of physiological functions in brain. The optical properties of the liquid circulating through the dynamic part can be changed to simulate the change in oxygenation states. The material of the skin layer has been changed from solid resin to soft rubber in order to have a good contact with optical fibers. The fabricated optical head phantom has been used in time-resolved spectroscopic measurement, and the usefulness of the dynamic optical head phantom is verified.
    研究論文(国際会議プロシーディングス), 英語
  • Fabrication of realistic and dynamic human head phantoms
    Yukari Tanikawa; Daigo Imai; Kenji Tanaka; Yukio Yamada
    JSME International Journal, Series C: Mechanical Systems, Machine Elements and Manufacturing, Japan Society of Mechanical Engineers, 42巻, 3号, 掲載ページ 487-491, 出版日 1999年, 査読付, Optical tomography will be a new modality of non-invasive diagnosis in medicine and biology, and is expected to image the distribution of optical properties in human bodies by measuring transmitted light at skin surfaces. In the process of developing optical tomographic imaging systems for diagnosis of disease and study of brain functions of human heads, we need realistic optical phantoms which anatomically and optically simulate human heads with complicated and multi-layered structures. In this study, we have fabricated optical phantoms based on MRI images of a human head. The phantoms had a multi-layered structure with different optical properties at five layers
    i.e., skin, skull, cerebrospinal fluid layer, gray matter and white matter. Also the phantoms which were mainly made of solid resin had dynamic parts to simulate the temporal variation of physiological functions in brain. The optical properties of the liquid circulating through the dynamic part can be changed to simulate the change in oxygenation states. The material of the skin layer was a soft rubber in order to achieve a good contact with optical fibers. The fabricated optical head phantom was checked by X-ray CT to see whether air bubbles were trapped or not, and to measure the size and cavity in the phantom.
    研究論文(学術雑誌), 英語
  • Simulation of 3D light propagation in a layered head model including a clear CSF layer, OSA TOPS
    S. Takahashi; Y. Yamada
    Advances in Optical Imaging and Photon Migration, 21巻, 掲載ページ 2-6, 出版日 1998年11月, 査読付
    研究論文(国際会議プロシーディングス), 英語
  • Propagation-loss prediction using ray tracing with a random-phase technique
    S Takahashi; Y Yamada
    IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES, IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG, E81A巻, 7号, 掲載ページ 1445-1451, 出版日 1998年07月, 査読付, For mobile telecommunication systems, it is important to accurately predict the propagation-path loss in terms of the estimation of the radiowave coverage area. The propagation-path loss has been estimated in a median obtained spatially from many received amplitudes (envelopes) within a region of several tens times as long as the wavelength, rather than in the envelopes themselves. Although ray tracing can obtain the envelopes and their median that reflect the site-dependent characteristics, the estimated median sometimes does not agree with the measured one. Therefore, the accuracy improvement has been expected. In this paper, an accuracy improvement is achieved by substituting a median with random phases for the median obtained spatially from many envelopes. The characteristic function method is used to obtain the cumulative distribution function and the median analytically where the phases are randomized. In a multipath environment, the phase-estimation error accompanying the location error of the ray tracing input influences the spatially obtained median. The phase-randomizing operation reduces the effects of the phase-estimation error on the median prediction. According to our estimation, improvements in accuracy of 4.9 dB for the maximum prediction error and 2.9 dB for the RMS prediction error were achieved. In addition, a probability-based cell-design method that takes the radiowave arrival probability and the interference probability into consideration is possible by using the percentiles obtained by the characteristic function method and the cell-design examples are shown in this paper.
    研究論文(学術雑誌), 英語
  • Determination of the asymmetry parameter and scattering coefficient of turbid media from spatially resolved reflectance measurements
    Matthew R. Jones; Yukio Yamada
    Optical Review, Optical Society of Japan, 5巻, 2号, 掲載ページ 72-76, 出版日 1998年, 査読付, We present a technique for determining the asymmetry parameter and scattering coefficient of turbid media from spatially resolved reflectance measurements. This technique will contribute to the development of medical applications in which it is necessary to predict the distribution and propagation of light in tissue. Based on Monte Carlo simulations, we derived correlations which relate the reduced scattering coefficient and the asymmetry parameter to the relative reflectance curve. Initial estimates of the optical properties are obtained from these correlations. Final values are obtained by adjusting the optical parameters and repeating the Monte Carlo simulations until the simulated reflectance pattern matches the measured reflectance pattern. Preliminary experimental results indicate that this technique can be used to determine the asymmetry parameter to within 10% and the reduced scattering coefficient to within 5%.
    研究論文(学術雑誌), 英語
  • A New Method of Bone Tissue Measurement Based upon Light Scattering (original article)
    Akira Takeuchi; Ryuichiro Araki; S. G. Proskurin; Yukari Takahashi; Yukio Yamada; Jun Ishii; Shigehiro Katayama; Akira Itabashi
    J Bone Miner Res, BLACKWELL SCIENCE INC, 12巻, 2号, 掲載ページ 261-266-266, 出版日 1997年02月, 査読付, In recent years, time-resolved spectroscopy systems using near infrared pulsed laser have been applied to develop optical computed tomography, We applied this technique to measure the optical properties of osseous tissue, First, we gradually demineralized 10 mm blocks of bovine trabecular bone with EDTA, maintaining the absorption characteristics and structure but varying the hydroxyapatite content, thus creating specimens differing only in light scattering properties, We used computer densitograms to assess light penetration, and analyzed the correlation with bone mineral density (BMD) as with dual-energy X-ray absorptiometry scans, The light penetration increased with decreasing BMD. Second, using the above-mentioned pulsed laser time-resolved spectroscopy system, we investigated the correlation between the BMD and the time response waveforms of 10-mm blocks of bovine cortical bone, trabecular bone, and surrounding tissue as well as human trabecular bone, The human lumbar vertebral bone also displayed an inverse correlation between BMD and maximum light penetration and a positive correlation between BMD and peak time delay, This is the first demonstration of a correlation between BMD and light scattering properties showing that BMD can indeed be measured with light, Our results show the possibility of obtaining information on internal bone structure and composition in vivo through assessment of the waveforms obtained by a time-resolution system in the near infrared region.
    研究論文(学術雑誌), 英語
  • Fundamental 3D FEM analysis of light propagation in head model toward 3D optical tomography
    S Takahashi; D Imai; Y TanikawaTakahashi; Y Yamada
    OPTICAL TOMOGRAPHY AND SPECTROSCOPY OF TISSUE: THEORY, INSTRUMENTATION, MODEL, AND HUMAN STUDIES II, PROCEEDINGS OF, SPIE - INT SOC OPTICAL ENGINEERING, 2979巻, 掲載ページ 250-260, 出版日 1997年, 査読付, Human head has anatomically and optically layered structure (skin, skull, gray and white matters), so that light propagates 3-Dimensionally in the head taking complicated paths. Revealing the light paths is necessarily required to solve inverse problems and realize 3-Dimensional optical tomography. In older to simulate the intracephalic light propagation, computational model for 3-Dimensional Finite Elements Method (FEM) was constructed. It had a hemispherical geometry and a layered distribution of scattering and absorption coefficients. The model consisted of 12528 elements, and the dimension of model, scattering and absorption coefficients of each element were assigned according to those of neonatal head. Impulse source was assumed, and boundary and initial conditions were appropriately given. Time-dependent photon diffusion equation was solved for fluence rate. And 3-Dimensional distribution of fluence rate and time-dependent light propagation were then obtained. Light paths between source and detectors were also calculated. These results were visualized using computer graphics techniques.
    研究論文(国際会議プロシーディングス), 英語
  • Measurements of time-resolved transmittances through cylindrical solid phantoms. Comparison with 2D and 3D FEM simulations
    SG Proskurin; S Takahashi; Kwee, I; Y Tanikawa; Y Yamada
    OPTICAL TOMOGRAPHY AND SPECTROSCOPY OF TISSUE: THEORY, INSTRUMENTATION, MODEL, AND HUMAN STUDIES II, PROCEEDINGS OF, SPIE - INT SOC OPTICAL ENGINEERING, 2979巻, 掲載ページ 261-271, 出版日 1997年, 査読付, Experimentally acquired time-resolved sind continuous-wave diffuse transmittances of near-infrared light through cylindrical solid phantoms are presented. Homogeneous and inhomogeneous tissue-like phantoms (68 mm diameter, epoxy resin) were used. The transmittances were acquired at 18 degrees intervals around the phantoms. Experimental results are compared with results of two dimensional and three dimensional finite-element simulations.
    The influence of absorbing boundaries on the shape of time-resolved and continuous-wave transmittances has been investigated for slab and cylindrical geometry. Analytical solutions of the photon diffusion equation with reflecting and absorbing boundary conditions were applied to estimate the optical properties of the material.
    A new index, time-resolved homogeneity index, is introduced for quick and simple inhomogeneity detection prior to image reconstruction.
    研究論文(国際会議プロシーディングス), 英語
  • 逆問題解法による光CTのシミュレーション
    JONES Matthew R.; 山田 幸生; 手塚 明
    日本機械学会論文集. A編, 一般社団法人日本機械学会, 62巻, 595号, 掲載ページ 842-846, 出版日 1996年03月25日, Optical computed tomography is a medical imaging modality in which red and near infrared light are used to probe biological tissues. Images are obtained by mapping the absorption coefficient of the tissue. Realization of clinically viable optical computed tomography depends on the development of reliable and fast methods of obtaining inverse solutions of the photon diffusion equation which describes the photon migration in biological tissues. In this paper we use a linearization and regularization technique and a finite element method to invert the diffusion approximation, and we propose the use of a zooming method as a way to improve the resolution of the images. We compare the performance of three regularization methods, i. e., the truncated singular value decomposition, Tikhonov regularization, and Phillips-Twomey regularization, The usefulness of the zooming method is demonstrated.
    日本語
  • Optical tomography by the temporally extrapolated absorbance method
    Ichiro Oda; Hideo Eda; Yoshio Tsunazawa; Michinosuke Takada; Yukio Yamada; Goro Nishimura; Mamoru Tamura
    Applied Optics, 35巻, 1号, 掲載ページ 169-175, 出版日 1996年01月01日, 査読付, The concept of the temporally extrapolated absorbance method (TEAM) for optical tomography of turbid media has been verified by fundamental experiments and image reconstruction. The TEAM uses the time-resolved spectroscopic data of the reference and object to provide projection data that are processed by conventional backprojection. Optical tomography images of a phantom consisting of axisymmetric double cylinders were experimentally obtained with the TEAM and time-gating and continuous-wave (CW) methods. The reconstructed TEAM images are compared with those obtained with the timegating and CW methods and are found to have better spatial resolution. © 1996 Optical Society of America.
    研究論文(学術雑誌), 英語
  • Optical tomography by the temporally extrapolated absorbance method
    Oda, I; H Eda; Y Tsunazawa; M Takada; Y Yamada; G Nishimura; M Tamura
    APPLIED OPTICS, OPTICAL SOC AMER, 35巻, 1号, 掲載ページ 169-175, 出版日 1996年01月, 査読付, The concept of the temporally extrapolated absorbance method (TEAM) for optical tomography of turbid media has been verified by fundamental experiments and image reconstruction. The TEAM uses the time-resolved spectroscopic data of the reference and object to provide projection data that are processed by conventional backprojection. Optical tomography images of a phantom consisting of axisymmetric double cylinders were experimentally obtained with the TEAM and time-gating and continuous-wave (CW) methods. The reconstructed TEAM images are compared with those obtained with the time-gating and CW methods and are found to have better spatial resolution. (C) 1996 Optical Society of America .
    研究論文(学術雑誌), 英語
  • OPTICAL CT USING TEMPORALLY EXTRAPOLATED ABSORBANCE METHOD (TEAM)
    ODA, I; H EDA; Y TSUNAZAWA; M TAKADA; Y YAMADA; G NISHIMURA; M TAMURA
    PHOTON TRANSPORT IN HIGHLY SCATTERING TISSUE, PROCEEDINGS OF, SPIE - INT SOC OPTICAL ENGINEERING, 2326巻, 掲載ページ 505-515, 出版日 1995年, 査読付
    研究論文(国際会議プロシーディングス), 英語
  • 生体内光伝播の高速時間分解計測
    高橋 ゆかり; 山田 幸生; 長谷川 裕夫
    計測自動制御学会論文集, The Society of Instrument and Control Engineers, 29巻, 8号, 掲載ページ 883-887, 出版日 1993年08月31日, Near-infrared light is considered to be able to diagnose the oxygenation state of living bodies, and time-resolved spectroscopy is expected to be promising for sophisticated optical tomographic measurement. However, because light is strongly scattered by living tissues, fundamental understanding of scattering characteristics of light through living tissues is needed. In this paper, fundamental experiment using homogeneous samples was carried out for understanding of light propagation and for estimation of scattering and absorption coefficients by time-resolved measurements. The experimental results were compared with numerical results which were obtained by the Monte-Carlo method and the Finite-Element method solving the time-dependent proton diffusion equation. Good agreement between them are obtained.
    日本語
  • 近赤外光を利用する医療診断
    山田 幸生
    熱物性, JAPAN SOCIETY OF THERMOPHYSICAL PROPERTIES, 7巻, 2号, 掲載ページ 115-120, 出版日 1993年, 生体組織・器官の活動度の指標となる組織の酸素化度を、 近赤外光を用い、 無侵襲で断層像として描き出す光CTの研究開発が行なわれている。 X線とは異なり、 光は生体により強く散乱されるため、 X線CTの方式や画像再構成アルゴリズムをそのまま適用することは困難である。 光が生体内でどのように伝播して行くかについての理解が先ず必要であり、 それに基づいた新しい画像再構成アルゴリズムの構築が期待されている。 ここでは光CT開発の現状と展望を述べる。
    日本語
  • 生体組織における光の挙動と光CTシミュレーション
    山田 幸生
    Medical Imaging Technology, 日本医用画像工学会, 10巻, 5号, 掲載ページ 490-490, 出版日 1992年
    日本語
  • 生体による光の散乱,吸収のモンテカルロ法によるシミュレーション
    長谷川 裕夫; 山田 幸生; 野村 保友; 田村 守
    日本機械学会論文集 B編, The Japan Society of Mechanical Engineers, 56巻, 524号, 掲載ページ 1173-1177, 出版日 1990年, The Monte Carlo method was used to analyze characteristics of light scattering and absorption by living bodies. The intensity of transmitted light through a slab of emulsion which simulates living bodies was calculated. The emulsion contained two types of particles ; small particles with isotropic scattering and large particles with strong forward scattering. Time-resolved analysis clarified the profile of transmitted light intensity, and the optical density, which is calculated from light attenuation caused by absorbing particles, was found to be in proportion to the absorption coefficient of particles and the optical path length. From spatial analysis of transmitted light intensity, the mean optical pathlengths have been found to be four to ten times the geometrical pathlength.
    日本語
  • スターリングエンジン用流動層熱交換器の基礎的研究
    山田 幸生
    日本機械学会論文集 B編, The Japan Society of Mechanical Engineers, 54巻, 507号, 掲載ページ 3284-3289, 出版日 1988年, The present study proposes to use fluidized bed heat exchangers to improve thermal performances of high temperature heat exchangers for Stirling engines. Seven pot-type heat exchangers consisting of U-tubes with 6 mm outer diameter were inserted in a hot fluidized bed to measure heat transfer coefficients at the outer tube surfaces in the bed temperature range up to 400°C. Three different sizes of alumina particles were used as the bed material. The effects of particle size, tube number, fin size, superficial velocity, bed temperature, etc., were investigated. Also, the uniformity in temperature in the fluidized bed was found to be food enough to be used for heat exchangers of Stirling engines.
    日本語

MISC

  • Numerical study of light scattering in the human neck for diagnosis of thyroid cancers by optical tomography
    藤井 宏之; 山田 幸生; 星 詳子; 小林 一道; 渡部 正夫
    出版日 2018年, Extended abstract of the 12th CME International Conference, OS12巻, 2号, 英語, 研究発表ペーパー・要旨(国際会議)
  • Numerical Calculation Of Time-resolved Light Reflectance From Biological Tissue Using The Radiative Transfer Equation
    Hiroyuki Fujii; Yukio Yamada; Yoko Hoshi; Kazumichi Kobayashi; Masao Watanabe
    出版日 2017年, Extended abstract of The International Conference on Mathematics in (bio)Chemical Kinetics and Engineering (MaCKiE) 2017, 英語, 研究発表ペーパー・要旨(国際会議)
  • 拡散光による甲状腺腫瘍診断のためのヒト頸部内における光伝播の数値解析
    藤井 宏之; 山田 幸生; 星 詳子; 小林 一道; 渡部 正夫
    出版日 2017年, 第33回近赤外フォーラム 講演論文集, I巻, 07号, 日本語, 研究発表ペーパー・要旨(全国大会,その他学術会議)
  • GS0610 エタノール水溶液の拡散係数の温度依存性に関する実験的考察
    山下 大樹; 角田 直人; 川嶋 大介; 近藤 克哉; 有本 英伸; 山田 幸生
    Temperature dependence of diffusion coefficient of ethanol in dilute ethanol aqueous solutions is investigated by using a simultaneous imaging method of temperature and concentration. The simultaneous imaging is achieved by absorption imaging with two wavelengths of 1905 nm and 1935 nm in the ν_2+ν_3 absorption band of water. The absorbance at 1905 nm is the most sensitive to the temperature in the band but that at 1935 nm is insensitive. Whereas, the absorbances at both wavelength are highly sensitive to the water molar fraction, which is inversely proportional to the ethanol concentration. When a 2 wt% ethanol aqueous solution and pure water flowed in parallel through a microfluidic channel, the concentration changes by diffusion mixing were measured at different temperatures, and the diffusion coefficients were determined by fitting the analytical solution of one-dimensional diffusion equation to the measured concentration data., 一般社団法人 日本機械学会, 出版日 2016年, 日本機械学会関東支部総会講演会講演論文集, 2016巻, 0号, 掲載ページ _GS0610-1_-_GS0610-2_, 日本語, 110010050007, AA11902161
  • 近赤外光を利用したマイクロ流路内の拡散現象の可視化
    角田 直人; 山下 大樹; 川嶋 大介; 近藤 克哉; 有本 英伸; 山田 幸生

    It is important and required for chemical analysis/synthesis using microfluidic channels to visualize diffusion phenomena and chemical reactions. We have thus developed a near-infrared (NIR) absorption imaging method to simultaneously measure the temperature and concentration distributions of aqueous solutions. This method is based on the fact that the ν2 + ν3 absorption band of water in an NIR region shifts to shorter wavelength as the temperature increases and that the band is very sensitive to the mole fraction of water. This paper shows the temperature and concentration images of aqueous solutions of methanol, ethanol, and glucose flowing in a Y-shaped microchannel. From the concentration images, the diffusion coefficient of each solute in water is determined by using a fitting function based on a one-dimensional diffusion equation, and its temperature dependence is quantitatively discussed.

    , 一般社団法人 日本機械学会, 出版日 2016年, 年次大会, 2016巻, 0号, 掲載ページ G0600703, 日本語, 130007063694
  • B122 液体中の発熱マイクロ粒子周りの温度分布推定(OS-8:マイクロ・ナノ熱工学(2))
    藤岡 良太; 角田 直人; 近藤 克哉; 有本 英伸; 山田 幸生
    Free convection generated in the fluid temperature difference by local heating, influences that can`t be ignored in heat transfer characteristics. Therefore, it is required to measure the amount of heat generated up to the free convection occurs. In previous studies, we've been estimated for the temperature distribution and the free convection around the micro heating magnetic sphere of mm size in the water. In this study, the micro particles under the alternating magnetic field over time imaging the absorbance at a wavelength of 1150 nm or 1412 nm, to estimate the temperature distribution by obtaining the absorbance of images. This time, we set up micro particles in the syrup, to estimate the temperature distribution from the absorbance image., 一般社団法人日本機械学会, 出版日 2015年10月23日, 熱工学コンファレンス講演論文集, 2015巻, 掲載ページ "B122-1"-"B122-2", 日本語, 110010045392, AA11901963
  • H215 水中の微小発熱球周りの自然対流場の3次元温度分布の推定(一般講演(11))
    三宅 智洋; 角田 直人; 藤岡 良太; 近藤 克哉; 有本 英伸; 山田 幸生
    We propose a novel method for estimating three-dimensional temperature distributions of water in a free convection field around a small heated sphere. This method consists of a near-infrared absorption imaging with a wavelength of 1150 nm and inverse Abel transform. Since temperature distributions formed by free convection above a heated sphere can be assumed to be axisymmetric ones, where the axis is in the opposite direction of gravity, the three-dimensional temperature distributions are reconstructed by applying the inverse Abel transform to every absorbance line profile perpendicular to the axis. The reconstructed temperature distributions show the transient process of free convection, indicating the validity of this method., 一般社団法人日本機械学会, 出版日 2015年10月23日, 熱工学コンファレンス講演論文集, 2015巻, 掲載ページ "H215-1"-"H215-2", 日本語, 110010045581, AA11901963
  • J0510204 近赤外光を用いた水溶液中の微小発熱領域の可視化
    角田 直人; 山田 健太; 藤岡 良太; 近藤 克哉; 有本 英伸; 山田 幸生
    This paper introduces a novel method for imaging the temperature fields in water with a small heated sphere. This method is based on the temperature dependence of the absorption coefficient of water at the wavelength of 1150 nm. When a 1 mm diameter steel sphere in water contained in a rectangular glass cell with a light path length of 10 mm was heated inductively by a 760 kHz magnetic field, the absorbance images at this wavelength were acquired by using a near-infrared imaging system. The images showed that the absorbances around the sphere increased, corresponding to the heating power levels, and that a circularly symmetric distribution was formed by thermal conduction in a certain initial period and subsequently upward flow occurred by free convection. To the circularly symmetric distributions, inverse Abel transform was applied, and radial temperature distributions were reconstructed., 一般社団法人日本機械学会, 出版日 2015年09月13日, 年次大会 : Mechanical Engineering Congress, Japan, 2015巻, 掲載ページ "J0510204-1"-"J0510204-3", 日本語, 110010048887, AA12588255
  • G221 近赤外吸収イメージング法を用いた中和反応界面近傍の濃度の計測(OS-12:先端計測による熱工学の学際的展開(3))
    川嶋 大介; 角田 直人; 近藤 克哉; 有本 英伸; 山田 幸生
    This paper focuses on the mixing phenomena at the neutralization reaction interface in a microchannel. Visualization of diffusion and chemical reaction of the aqueous solutions of hydrochloric acid and sodium hydroxide in microchannel is performed by using a novel imaging technique based on the near-infrared absorption spectroscopy of aqueous solutions. We observe the salt generation and diffusion by the reaction when the flow of the two reagents and gravitational directions are changed. The results show that salt diffusion phenomena are greatly influenced by gravitational direction., 一般社団法人 日本機械学会, 出版日 2015年, 熱工学コンファレンス講演論文集, 2015巻, 0号, 掲載ページ _G221-1_-_G221-2_, 日本語, 110010045555, AA11901963
  • H214 近赤外吸収特性を利用したエタノール水溶液の拡散現象の観察(一般講演(11))
    山下 大樹; 角田 直人; 川嶋 大介; 近藤 克哉; 有本 英伸; 山田 幸生
    This paper presents a simultaneous imaging method of the temperature and concentration of ethanol aqueous solutions in a microchannel. Absorbance images at the two wavelengths in the ν_2 + ν_3 absorption band of water: 1905 nm and 1935 nm, are simultaneously acquired and converted to the temperature and concentration images. The absorbance at 1905 nm is the most sensitive to the temperature in the band, but that at 1935 nm is insensitive, i.e., an isosbestic point. Whereas, the absorbances at both wavelength are highly sensitive to the water molar fraction, which is inversely proportional to the ethanol concentration. When a 2 wt% ethanol aqueous solution and pure water meet and diffuse to each other, changes in the concentration are observed, and the temperature dependence of the diffusion coefficient is discussed., 一般社団法人 日本機械学会, 出版日 2015年, 熱工学コンファレンス講演論文集, 2015巻, 0号, 掲載ページ _H214-1_-_H214-2_, 日本語, 110010045580, AA11901963
  • 生体光イメージングのためのヒト頸部内光伝播モデルの構築
    藤井 宏之; 大川 晋平; 灘本 健; 岡田 英史; 山田 幸生; 星 詳子; 渡部 正夫
    出版日 2015年01月, バイオエンジニアリング講演会講演論文集, 2015.27巻, 1G21号, 日本語, 研究発表ペーパー・要旨(全国大会,その他学術会議)
  • D211 近赤外吸収イメージング法を応用した高周波磁場下における微小磁性球の発熱量推定
    山田 健太; 角田 直人; 藤岡 良太; 近藤 克哉; 有本 英伸; 山田 幸生
    This paper presents a novel method for reconstructing the temperature distributions of water around a small heated sphere and predicting the heat generation rates of the sphere. This method is based on the temperature dependence of the absorbance of water at the wavelength of 1150 nm. Absorbance images at 1150 nm were obtained when a 1 mm diameter steel sphere located in water contained in a glass cell with a light path length of 10 mm was heated by a 760 kHz alternating magnetic field. Inverse Abel transform is applied to the line profiles of the absorbance, and radial temperature distributions are reconstructed. The heat generation rates calculated from these temperature distributions well agree with induction heating power levels., 一般社団法人日本機械学会, 出版日 2014年11月08日, 熱工学コンファレンス講演論文集, 2014巻, 掲載ページ "D211-1"-"D211-2", 日本語, 110009939013, AA11901963
  • H215 水中の微小発熱球周りの自然対流の開始時間
    藤岡 良太; 角田 直大; 山田 健太; 近藤 克哉; 有本 英伸; 山田 幸生
    This paper describes the onset of free convection around a 1 mm diameter steel sphere heated inductively in water using a light absorption imaging method with a wavelength of 1150 nm. Since the concentric absorbance distributions formed by pure thermal conduction are distorted by free convection, the onsets of free convection are determined by measuring the position of a centroid of a region with a certain absorbance and compared to Rayleigh number., 一般社団法人日本機械学会, 出版日 2014年11月08日, 熱工学コンファレンス講演論文集, 2014巻, 掲載ページ "H215-1"-"H215-2", 日本語, 110009939105, AA11901963
  • 1B13 一般化パルススペクトル法を用いた蛍光トモグラフィーの三次元画像再構成(GS5:画像解析)
    竹越 雅史; 大川 晋平; 正本 和人; 西村 吾朗; 山田 幸生
    一般社団法人日本機械学会, 出版日 2014年01月10日, バイオエンジニアリング講演会講演論文集, 2014巻, 26号, 掲載ページ 47-48, 日本語, 110009955987, AA11903175
  • D142 近赤外域の2波長同時イメージング法を利用したマイクロ流路内の発熱反応の可視化 : 近赤外吸収画像による酸塩基中和反応の考察
    川嶋 大介; 角田 直人; 近藤 克哉; 有本 英伸; 山田 幸生
    This paper presents the visualization of neutralization reactions of an acid (HCl) and a base (NaOH) in a microchannel. Increases in temperature and concentration of the products, caused by the neutralization reactions, are visualized by using the absorbance images at two wavelengths in a near-infrared region: 1412 nm and 1442 nm. Absorbance images at 1412 nm reflect the temperature increases because the absorbance increases with the elevation of temperature. Absorbance images at 1442 nm reflect the concentrations of the products because the absorbance is insensitive to the temperature but sensitive to the concentrations. The absorbance increment caused by heat generation is observed at 1412 nm and that increment caused by products, salt and water, is observed at 1442 nm, respectively., 一般社団法人 日本機械学会, 出版日 2014年, 熱工学コンファレンス講演論文集, 2014巻, 0号, 掲載ページ _D142-1_-_D142-2_, 日本語, 110009939010, AA11901963
  • 22am2-F8 近赤外吸収イメージング法を応用したマイクロ流路内の酸・アルカリ水溶液混合場の観察
    川嶋 大介; 角田 直人; 近藤 克哉; 有本 英伸; 山田 幸生
    This study aims to visualize the mixing and chemical reactions of aqueous solutions in microchannels by using a near-infrared absorption imaging technique based on the spectral characteristics of water and solutes. This paper focuses on the effect of the salt generated from neutralization reaction of HCl and NaOH aqueous solutions on the spectra, and tries to construct the concentration images of the salt by using absorbance difference images at the wavelength of 1412 nm and 1442 nm., 一般社団法人 日本機械学会, 出版日 2014年, マイクロ・ナノ工学シンポジウム, 2014巻, 0号, 掲載ページ _22am2-F8--_22am2-F8-, 日本語, 110009950736, AA12456946
  • F113 近赤外吸収イメージング法を応用した微小発熱粒子周りの水の温度分布推定(一般講演(7))
    山田 健太; 角田 直人; 有本 英伸; 近藤 克哉; 山田 幸生
    This paper presents a method of reconstructing the temperature distributions of water around a small heated sphere. This method is based on the temperature dependence of the absorbance of water at the wavelength of 975 nm. Absorbance images at this wavelength were obtained when an iron sphere with a diameter of 1 mm located in water contained in a glass cell with a light path length of 10 mm was heated by a high-frequency magnetic field. Inverse Abel transform was applied to the line profiles of the absorbance, and cross-sectional temperature distributions around the sphere were reconstructed. The temperature distributions vary with the magnitudes of the magnetic field, which indicates the possibility of quantitative evaluation of induction heating systems., 一般社団法人日本機械学会, 出版日 2013年10月18日, 熱工学コンファレンス講演論文集, 2013巻, 掲載ページ 167-168, 日本語, 110009955675, AA11901963
  • 3F08 マウス大脳皮質におけるグルコース輸送の生体二光子顕微鏡イメージング(GS20-2:生体計測(2))
    高田 優季; 村田 濡; 田桑 弘之; 菅野 巖; 伊藤 浩; 山田 幸生; 正本 和人
    一般社団法人日本機械学会, 出版日 2013年01月08日, バイオエンジニアリング講演会講演論文集, 2013巻, 25号, 掲載ページ 633-634, 日本語, 110009920196, AA11903175
  • 3F09 層構造を持つヒト皮膚内光学特性値分布の再構成(GS20-2:生体計測(2))
    小菅 朋也; 大川 晋平; 正本 和人; 山田 幸生
    一般社団法人日本機械学会, 出版日 2013年01月08日, バイオエンジニアリング講演会講演論文集, 2013巻, 25号, 掲載ページ 635-636, 日本語, 110009920197, AA11903175
  • 1F03 磁気ハイパーサーミアin vitro実験のための発熱粒子周りの温度分布推定法(GS17-1:バイオヒート・マストランスポート(1))
    角田 直人; 山田 健太; 近藤 克哉; 中田 智士; 有本 英伸; 山田 幸生
    一般社団法人日本機械学会, 出版日 2013年01月08日, バイオエンジニアリング講演会講演論文集, 2013巻, 25号, 掲載ページ 183-184, 日本語, 110009919969, AA11903175
  • 水の近赤外吸収特性を利用した非接触温度イメージング
    角田 直人; 近藤 克哉; 有本 英伸; 山田 幸生
    システム制御情報学会, 出版日 2013年, システム・制御・情報 = Systems, control and information : システム制御情報学会誌, 57巻, 12号, 掲載ページ 493-498, 日本語, 0916-1600, 110009685989, AN10062329
  • F112 近赤外域の2波長同時イメージング法を利用したマイクロ流路内の発熱反応の可視化 : HClとNaOH水溶液の吸収スペクトルと2波長画像の考察(一般講演(7))
    川嶋 大介; 角田 直人; 近藤 克哉; 有本 英伸; 山田 幸生
    This paper presents the visualization of heat and mass transfer of aqueous solutions in microchannels by using the simultaneous imaging method of the temperature and solute concentration. This method is based on the absorption characteristics of water in a near-infrared region: absorbance at a wavelength of 1412 nm is dependent on the temperature whereas that at 1442 nm is independent. This visualization method is applied to experimental researches on chemical reactions between hydrochloric acid and sodium hydroxide aqueous solutions. These two reagents are supplied into two inlets of a Y-shaped rectangular microchannel at several different flow rates. Absorbance difference images in the merging region of the two flows are obtained at the two wavelengths simultaneously, which demonstrate that the magnitude and distribution of the absorbance difference vary with the concentrations and flow rates., 一般社団法人 日本機械学会, 出版日 2013年, 熱工学コンファレンス講演論文集, 2013巻, 0号, 掲載ページ 165-166, 日本語, 110009955674, AA11901963
  • P-G1-2 水の近赤外吸収特性に基づく水溶液の温度と水体積分率の同時イメージング(P-G1 マイクロ熱流体,ポスターセッション論文)
    角田 直人; 近藤 克哉; 有本 英伸; 山田 幸生
    A remote and marker-free method for simultaneously imaging the temperature and the volume fraction of water (VFW) of aqueous solutions in mini/microchannels is presented. The principle of this method is based on the temperature dependence of the near-infrared absorption band (ν_1+ν_3 band) of water. An absorbance image at the wavelength of 1412 nm, the most sensitive to temperature in the band, and that at 1445 nm, isosbestic point, were alternately obtained, each at 10 frames/s, by using an alternate narrow-bandpass filtering system and a near-infrared camera. The 1412 nm-images demonstrated a change in temperature distribution caused by the inflow of heated water. A change in VFW appeared in the images at the both wavelengths and it was confirmed that the VFW was nearly proportional to the concentration of ethanol as a solute., 一般社団法人日本機械学会, 出版日 2012年10月21日, マイクロ・ナノ工学シンポジウム, 2012巻, 4号, 掲載ページ 193-194, 日本語, 110009953458, AA12456946
  • G060065 近赤外温度イメージング法を利用した発熱細線周りの水の温度分布推定
    角田 直人; 近藤 克哉; 中田 智士; 有本 英伸; 山田 幸生
    A prediction method of internal temperatures distributed axisymmetrically in an aqueous solution with a thickness from sub-mm to a few mm is presented. This method consists of a near-infrared (NIR) absorption imaging and an inverse Abel transform. In the NIR absorption imaging, absorbance images at the wavelength of 1412 nm, the most temperature-sensitive wavelength in the v_1 + v_3 absorption band of water, are obtained by using a narrow-bandpass filter and an NIR camera. In the case that the internal temperature possesses an axisymmetric distribution, it can be predicted by Abel inversion of the measured absorbance profile. In this study the absorbance profiles are approximated by multi-Gaussian functions because their inverse transform can be calculated analytically. Cross-sectional temperature distributions around a thin hot wire in 1.5 mm thick water are shown., 一般社団法人日本機械学会, 出版日 2012年09月09日, 年次大会 : Mechanical Engineering Congress, Japan, 2012巻, 掲載ページ "G060065-1"-"G060065-3", 日本語, 110009994294, AA12588255
  • 7D24 脳内グルコースの血管-細胞間の輸送動態解析(GS10 生体計測(解析))
    高田 優希; 吉原 光一; 田桑 弘之; 管野 巌; 伊藤 浩; 大川 晋平; 山田 幸生; 正本 和
    一般社団法人日本機械学会, 出版日 2012年01月06日, バイオエンジニアリング講演会講演論文集, 2012巻, 24号, 掲載ページ "7D24-1"-"7D24-2", 日本語, 110009688978, AA11903175
  • 7D21 ファントムを用いた蛍光トモグラフィーの擬似3次元画像化(GS10 生体計測(解析))
    吉田 昌記; 三井 陽平; 竹越 雅史; 星 詳子; 黄田 育宏; 大川 晋平; 正本 和人; 山田 幸生
    一般社団法人日本機械学会, 出版日 2012年01月06日, バイオエンジニアリング講演会講演論文集, 2012巻, 24号, 掲載ページ "7D21-1"-"7D21-2", 日本語, 110009688975, AA11903175
  • 蛍光イメージングによる脳微小血管血流速の計測
    山口大貴; 吉原光一; 須貸拓馬; 白畑大悟; 田桑弘之; 川口拓之; 伊藤浩; 大川晋平; 正本和人; 菅野巖; 山田幸生
    一般社団法人日本機械学会, 出版日 2012年01月06日, バイオエンジニアリング講演会講演論文集, 24th (CD-ROM)巻, 24号, 掲載ページ ROMBUNNO.7D47-1"-"7D47-2", 日本語, 1348-2920, 201202287731761811, 110009688993, AA11903175
  • 脳微小血管ネットワーク構造の定量解析法
    須貸拓馬; 吉原光一; 山口大貴; 白畑大悟; 川口拓之; 菅野巖; 伊藤浩; 大川晋平; 正本和人; 山田幸生
    一般社団法人日本機械学会, 出版日 2012年01月06日, バイオエンジニアリング講演会講演論文集, 24th (CD-ROM)巻, 24号, 掲載ページ ROMBUNNO.7D22-1"-"7D22-2", 日本語, 1348-2920, 201202237345816000, 110009688976, AA11903175
  • 生体組織の散乱が二光子顕微鏡イメージングの空間分解能に与える影響
    白畑大悟; 吉原光一; 須貸拓馬; 山口大貴; 川口拓之; 菅野巖; 伊藤浩; 大川晋平; 正本和人; 山田幸生
    一般社団法人日本機械学会, 出版日 2012年01月06日, バイオエンジニアリング講演会講演論文集, 24th (CD-ROM)巻, 24号, 掲載ページ ROMBUNNO.7D42-1"-"7D42-2", 日本語, 1348-2920, 201202298711776083, 110009688988, AA11903175
  • ダイナミック・マルチレベル生体光イメージング : 拡散光・蛍光トモグラフィ (特集 分子イメージングの最先端(後編))
    星 詳子; 山田 幸生
    寺田国際事務所先端医療技術研究所, 出版日 2012年, PET journal, 20号, 掲載ページ 9-12, 日本語, 2186-022X, 40019550375
  • 6-5 水の近赤外吸収特性を利用したマイクロ流路内水溶液の温度イメージング(セッション6:マイクロ物理センサ)
    角田 直人; 福原 悠子; 近藤 克哉; 有本 英伸; 山田 幸生
    This paper presents a remote and preparation-free method of temperature imaging of aqueous solutions in microchannels of micro-fluidic chips. The principle of this method is based on the temperature dependency of the near-infrared absorption band (v_2+v_3 band) of water. Temperature images were constructed from absorbances at the wavelength of 1908nm, the most sensitive to temperature in the band, measured by using a near-infrared camera and optical narrow-bandpass filter. Calculation and calibration results demonstrated a temperature coefficient of 1.5×10^<-2>K^<-1>mm^<-1>. Temperature images of 0.05mm thick water in a Y-shaped PDMS microchannel locally heated by a neighboring hot wire were obtained, in which thermal diffusion processes in the microchip were visualized., 一般社団法人日本機械学会, 出版日 2011年09月25日, マイクロ・ナノ工学シンポジウム, 2011巻, 3号, 掲載ページ 67-68, 日本語, 110009664142, AA12456946
  • 日本伝熱学会学術賞を受賞して
    角田 直人; 近藤 克哉; 尾崎 敦之; 有本 英伸; 山田 幸生
    出版日 2011年07月01日, 伝熱 : journal of the Heat Transfer Society of Japan, 50巻, 212号, 掲載ページ 5-5, 日本語, 1344-8692, 10029327153, AA11315621
  • G34 近赤外温度イメージングに及ぼす薄膜水溶液の厚さの影響(G3マイクロ・ナノ熱工学I)
    福原 悠子; 角田 直人; 近藤 克哉; 有本 英伸; 山田 幸生
    一般社団法人日本機械学会, 出版日 2011年03月17日, 日本機械学会九州支部講演論文集, 2011巻, 64号, 掲載ページ 263-264, 日本語, 110009666768, AN0036066X
  • 8I-17 ヒト皮膚の光学特性値の測定(OS-12 バイオヒート・マストランスファー(2))
    服部 和久; 桑原 智裕; 大川 晋平; 正本 和人; 小倉 有紀; 多島 新吾; 近江 雅人; 春名 正光; 山田 幸生
    一般社団法人日本機械学会, 出版日 2011年01月07日, バイオエンジニアリング講演会講演論文集, 2010巻, 23号, 掲載ページ 293-294, 日本語, 110008744138, AA11903175
  • 8I-16 酸素環境に依存した脳微小血管の定量評価(OS-12 バイオヒート・マストランスファー(2))
    坂本 良太; 吉原 光一; 朝賀 龍太郎; 大川 晋平; 正本 和人; 菅野 巖; 山田 幸生
    一般社団法人日本機械学会, 出版日 2011年01月07日, バイオエンジニアリング講演会講演論文集, 2010巻, 23号, 掲載ページ 291-292, 日本語, 110008744137, AA11903175
  • 8I-15 脳内蛍光グルコースの時空間動態の解析(OS-12 バイオヒート・マストランスファー(2))
    朝賀 龍太郎; 吉原 光一; 坂本 良太; 大川 晋平; 正本 和人; 菅野 巖; 山田 幸生
    一般社団法人日本機械学会, 出版日 2011年01月07日, バイオエンジニアリング講演会講演論文集, 2010巻, 23号, 掲載ページ 289-290, 日本語, 110008744136, AA11903175
  • 生物発光・蛍光と生体イメージング
    山田幸生; 大川晋平; 正本和人
    日本伝熱学会, 出版日 2011年01月, 伝熱, 50巻, 210号, 掲載ページ 25-30, 日本語, 記事・総説・解説・論説等(その他), 1344-8692, 10027724559, AA11315621
  • タイムラプス二光子顕微鏡で取得したマウス大脳皮質における脳微小血管構造の4次元解析
    吉原光一; 川口拓之; 田桑弘之; 小畠隆行; 大川晋平; 正本和人; 菅野巖; 山田幸生
    出版日 2010年11月08日, Optics & Photonics Japan講演予稿集, 2010巻, 掲載ページ 380-381, 日本語, 201102286102470800
  • B122 近赤外分光法を応用したマイクロ流路内水溶液の温度測定(OS-9:太陽熱利用(II)・一般講演)
    角田 直人; 福原 悠子; 近藤 克哉; 有本 英伸; 山田 幸生
    Temperature measurement of aqueous solution in a micro-fluidic chip by using near-infrared spectroscopy is presented. The principle is based on the temperature dependence of the v_2 + v_3 absorption band of water. Absorbance spectra for two areas in 50-μm thick water in a temperature controlled Y-channel were measured simultaneously by two photospectrometers. The spectra indicated the temperature difference between the two areas. The images of absorbance at 1905 nm corresponding to temperature images were obtained by using a near-infrared camera and narrow bandpass filter. Calibration measurements on water in the Y-channel from 24.0℃ to 46.0℃ demonstrated a temperature coefficient of 4.5 x 10^<-4>℃^<-1>. Finally, temperature distributions caused by a heating wire were visualized., 一般社団法人日本機械学会, 出版日 2010年10月29日, 熱工学コンファレンス講演論文集, 2010巻, 掲載ページ 41-42, 日本語, 110008742655, AA11901963
  • Involvement of dermal carbonyl modification in yellowish change of skin color with photo-aging in Japanese
    Yuki Ogura; Tomohiro Kuwahara; Tetsuji Hirao; Minoru Akiyama; Shingo Tajima; Kazuhisa Hattori; Kouhei Okamoto; Shinpei Okawa; Yukio Yamada; Hachiro Tagami; Motoji Takahashi
    WILEY-BLACKWELL PUBLISHING, INC, 出版日 2010年09月, JOURNAL OF DERMATOLOGY, 37巻, 掲載ページ 73-73, 英語, 研究発表ペーパー・要旨(国際会議), 0385-2407, WOS:000281733400277
  • 0825 ヒト角層の光学特性(OS31:先端レーザー診断・治療におけるTR(Translational Research)
    服部 和久; 岡本 光平; 畠山 宗也; 桑原 智裕; 近江 雅人; 春名 正光; 大川 晋平; 山田 幸生
    一般社団法人日本機械学会, 出版日 2010年01月08日, バイオエンジニアリング講演会講演論文集, 2009巻, 22号, 掲載ページ 320-320, 日本語, 110008064698, AA11903175
  • 1033 3次元拡散光トモグラフィのシミュレーション(OS26:脳機能およびその光計測)
    内田 和浩; 松橋 翔子; 星 詳子; 大川 晋平; 山田 幸生
    一般社団法人日本機械学会, 出版日 2010年01月08日, バイオエンジニアリング講演会講演論文集, 2009巻, 22号, 掲載ページ 366-366, 日本語, 110008064743, AA11903175
  • 1034 二光子励起法による脳組織光学特性の波長依存性を考慮した生体内脳微小血管イメージング(OS26:脳機能およびその光計測)
    吉原 光一; 米家 一洋; 正本 和人; 大川 晋平; 菅野 巖; 谷下 一夫; 山田 幸生
    一般社団法人日本機械学会, 出版日 2010年01月08日, バイオエンジニアリング講演会講演論文集, 2009巻, 22号, 掲載ページ 367-367, 日本語, 110008064744, AA11903175
  • 1111 光伝播シミュレーションを用いた近赤外分光法による非侵襲血糖値測定法(OS15-1:バイオトランスポート1)
    結束 祥子; 丸尾 勝彦; 大川 晋平; 山田 幸生
    一般社団法人日本機械学会, 出版日 2010年01月08日, バイオエンジニアリング講演会講演論文集, 2009巻, 22号, 掲載ページ 197-197, 日本語, 110008064576, AA11903175
  • 1113 光散乱体中における蛍光特性の測定(OS15-1:バイオトランスポート1)
    丸岡 正二; 内田 和希; 三井 陽平; 大川 晋平; 星 詳子; 山田 幸生
    一般社団法人日本機械学会, 出版日 2010年01月08日, バイオエンジニアリング講演会講演論文集, 2009巻, 22号, 掲載ページ 199-199, 日本語, 110008064578, AA11903175
  • 二光子励起イメージングにおける生体組織の散乱の影響
    吉原光一; 正本和人; 川口拓之; 大川晋平; 菅野巖; 山田幸生
    出版日 2010年, 酸素ダイナミクス研究会プログラム・抄録集, 14th巻, 掲載ページ 51, 日本語, 201102219893617606
  • ブタ頭部の光学特性値の in vivo 測定実験
    谷川 ゆかり; SASSAROLI Angelo; MARTELLI Fabrizio; 今井 大吾; 田中 健之; 荒木 隆一郎; 山田 幸生
    出版日 2009年11月12日, 電気学会研究会資料. LAV, 光応用・視覚研究会, 1999巻, 18号, 掲載ページ 7-11, 日本語, 10024607986, AN00346658
  • 積分球および時間分解測定による生体組織の光学特性測定
    田中 健之; 谷川 ゆかり; 荒木 隆一郎; 河村 洋; 山田 幸生
    出版日 2009年11月12日, 電気学会研究会資料. LAV, 光応用・視覚研究会, 1999巻, 18号, 掲載ページ 1-5, 日本語, 10024607979, AN00346658
  • 生体光伝播シミュレーションの近赤外線分光法への応用
    岡田英史; 川口拓之; 坂口浩一郎; 山田幸生
    出版日 2009年07月, 脈管学, 49巻, 2号, 掲載ページ 113-119, 日本語, 記事・総説・解説・論説等(その他)
  • 樹脂材料のレーザー溶着技術---光散乱材料の光学特性値測定と溶着性能の評価
    山田幸生; 黒﨑晏夫; 又吉智也
    大成社, 出版日 2009年03月, Polyfile, 46巻, 541号, 掲載ページ 14-19, 日本語, 記事・総説・解説・論説等(その他), 0910-2175, 40016575933, AN10153107
  • 111 光マッピング画像に対する脳脊髄液層及び頭蓋骨層厚さの影響(OS6-2:生体モデリングとシミュレーション(2),OS6:生体モデリングとシミュレーション)
    王 淑萍; 芝原 奈々恵; 倉増 大士; 大川 晋平; 角田 直人; 岡田 英史; 牧 敦; 山田 幸生
    一般社団法人日本機械学会, 出版日 2009年01月22日, バイオエンジニアリング講演会講演論文集, 2008巻, 21号, 掲載ページ 21-22, 英語, 110007706272, AA11903175
  • B219 拡散光トモグラフィを用いたハンドグリップ運動時のヒト前腕のin vivo測定(生体計測)
    谷川 ゆかり; 高 峰; 宮崎 康彰; 岩田 直之; 中村 康雄; 大川 晋平; 山田 幸生; 木竜 徹; 宮川 道夫
    時間分解法を応用した拡散光トモグラフィ装置は、光減衰量のみならず、パルスの到達時間から光路長を推定することができるため、定量的な評価が可能な装置と言われている。本研究では、この拡散光トモグラフィ装置の運動効果の定量評価への適用可能性を調べるため、ヒト前腕に放射状にファイバを設置し、ハンドグリップ圧縮運動を対象にin vivoで測定を行った。さらにこの結果を画像再構成アルゴリズムで解析し、運動時および安静時の計測からヒト前腕の酸素飽和度変化の断層画像再構成を行った。, 一般社団法人日本機械学会, 出版日 2008年09月22日, バイオフロンティア講演会講演論文集, 2008巻, 19号, 掲載ページ 75-76, 日本語, 1348-2939, 110007705764, AA11902434
  • B217 光マッピング技術における頭部構造の影響(生体計測)
    大木 万里子; 芝原 奈々恵; 冨樫 陵; 王 淑萍; 大川 晋平; 星 詳子; 山田 幸生
    一般社団法人日本機械学会, 出版日 2008年09月22日, バイオフロンティア講演会講演論文集, 2008巻, 19号, 掲載ページ 71-72, 日本語, 1348-2939, 110007705762, AA11902434
  • マイクロナノバイオエンジニアリングにおける輸送現象
    谷下一夫; 山田幸生
    出版日 2008年07月, 日本機械学会誌, 111巻, 1076号, 掲載ページ 573, 日本語, 記事・総説・解説・論説等(その他)
  • WS(4) 近赤外分光法を利用した培養細胞の熱測定(WS バイオトランスポートの新展開,ワークショップ)
    角田 直人; 尾崎 敦之; 近藤 克哉; 有本 英伸; 山田 幸生
    一般社団法人日本機械学会, 出版日 2008年03月13日, 日本機械学会関東支部総会講演会講演論文集, 2008巻, 14号, 掲載ページ 19-22, 日本語, 110007705074, AA11902161
  • 近赤外光による生体内血液状態分布測定技術
    山田幸生
    出版日 2008年02月, 冷凍, 83巻, 965号, 掲載ページ 167-172, 日本語, 記事・総説・解説・論説等(その他)
  • 205 線形逆問題解法を用いた血小板凝集反応の定量化(OS2-2:生体モデリングとシミュレーション(2),OS2:生体モデリングとシミュレーション)
    廣野 泰亮; 大川 晋平; 山田 幸生
    一般社団法人日本機械学会, 出版日 2008年01月24日, バイオエンジニアリング講演会講演論文集, 2007巻, 20号, 掲載ページ 49-50, 日本語, 110007085283, AA11903175
  • Imaging hemodynamic changes in preterm infant brains with two-dimensional diffuse optical tomography
    Feng Gao; Yiwen Ma; Fang Yang; Huijuan Zhao; Jingying Jiang; Takashi Kusaka; Masanori Ueno; Yukio Yamada
    We present our preliminary results on two-dimensional (2-D) optical tomographic imaging of hemodynamic changes of two preterm infant brains in different ventilation settings conditions. The investigations use the established two-wavelength, 16-channel time-correlated single photon counting system for the detection, and the generalized pulse spectrum technique based algorithm for the image reconstruction. The experiments demonstrate that two-dimensional diffuse optical tomography may be a potent and relatively simple way of investigating the functions and neural development of infant brains in the perinatal period., SPIE-INT SOC OPTICAL ENGINEERING, 出版日 2008年, ADVANCED BIOMEDICAL AND CLINICAL DIAGNOSTIC SYSTEMS VI, 6848巻, 英語, 0277-786X, 42149136347, WOS:000255549900021
  • Temperature measurement of bio-micro-aqueous solutions using near-infrared spectroscopy
    N. Kakuta; A. Ozaki; H. Arimoto; Y. Yamada
    IOS PRESS, 出版日 2008年, BIORHEOLOGY, 45巻, 1-2号, 掲載ページ 100-101, 英語, 研究発表ペーパー・要旨(国際会議), 0006-355X, WOS:000258929100134
  • 近赤外分光法による脳機能計測の基礎,歴史と最近の動向
    山田幸生
    出版日 2007年12月, 光学, 36巻, 12号, 掲載ページ 676-685, 日本語, 記事・総説・解説・論説等(その他)
  • F243 近赤外分光法を用いた褐色脂肪細胞の温度測定(生体)
    尾崎 敦之; 角田 直人; 有本 英伸; 山田 幸生
    This paper introduces a method of temperature measurement of brown adipose cells using near-infrared spectroscopy. The measurement principle is based on the fact that the peak wavelength of the water absorption band with its center near 1910nm shifts with changes in temperature. We developed a measurement system for temperature changes of brown adipose cells cultured on a 60-mm-dish. To induce the heat production of the brown adipose cells, norepinephrine was added to the culture solution during measurement. Irregular changes of absorption coefficient at 1908nm were observed after the norepinephrine administration. However, the relationship between these changes and temperature has not been clear., 一般社団法人日本機械学会, 出版日 2007年11月23日, 熱工学コンファレンス講演論文集, 2007巻, 掲載ページ 393-394, 日本語, 110007082930, AA11901963
  • C115 近赤外カメラを用いたsub-mm厚さの水の温度イメージング(温度計測)
    角田 直人; 尾崎 敦之; 近藤 克哉; 有本 英伸; 山田 幸生
    We report a method using near-infrared camera and optical filter to obtain the temperature image of sub-millimeter-thick water. The measurement principle is based on the fact that the peak wavelength of the water absorption band with its center near 1440nm shifts with changes in temperature. Temperature images can be constructed by calculating absorbances near 1412nm, which most strongly depend on temperature, for all pixels. We first calibrated the temperatures of 0.5-mm-thick water over the temperature range from 26.0℃ to 40.0℃. The average of temperature coefficients obtained was 1.46×10^<-3> absorbance/℃. Finally, we formed the temperature distribution in this water film by heating an immersed nichrome wire and obtained sequential temperature images demonstrating the distribution., 一般社団法人日本機械学会, 出版日 2007年11月23日, 熱工学コンファレンス講演論文集, 2007巻, 掲載ページ 105-106, 日本語, 110007083109, AA11901963
  • Two-dimensional optical tomography of hemo-dynamic changes in a preterm infant brain
    Feng Gao; Yuan Xue; Huijuan Zhao; Takashi Kusaka; Masanori Ueno; Yukio Yamada
    SCIENCE CHINA PRESS, 出版日 2007年08月, CHINESE OPTICS LETTERS, 5巻, 8号, 掲載ページ 472-474, 英語, 1671-7694, 34648846844, WOS:000255024100013
  • 3.多重散乱系での光伝播に関する光学特性値と基礎方程式
    山田幸生
    NTS出版, 出版日 2007年, 非侵襲・可視化技術ハンドブック., 掲載ページ 272-275, 20001638112
  • 616 皮溝・皮丘が皮膚内光伝播に与える影響(GS-4 皮膚と膠原繊維,一般セッション,学術講演)
    間下 友加里; 有本 英伸; 角田 直人; 山田 幸生; 太田 智浩; 丸尾 勝彦
    一般社団法人日本機械学会, 出版日 2006年01月12日, バイオエンジニアリング講演会講演論文集, 2005巻, 18号, 掲載ページ 409-410, 日本語, 110006205625, AA11903175
  • 540 近赤外光を用いた微小生体試料の温度測定のための基礎研究(GS-14 診断・治療,一般セッション,学術講演)
    李 富国; 角田 直人; 有本 英伸; 山田 幸生
    We have proposed a method for non-invasively measuring the temperature changes of water in a micro-region using near infrared (NIR) light. The goal of this study is to measure the temperature changes of biological cells or tissues. This method is on the basis of the phenomenon that the NIR absorption spectrum of water depends on temperature. Absorbance spectra in the wavelength range of 1300-2000nm of water with a thickness of 100 and 500μm were measured by a micro-spectrometer. Also, glucose solution was measured. The measured spectra with temperature-dependence were calibrated using a regression analysis. The standard error of calibration was 0.1-0.3℃., 一般社団法人日本機械学会, 出版日 2006年01月12日, バイオエンジニアリング講演会講演論文集, 2005巻, 18号, 掲載ページ 379-380, 日本語, 110006205610, AA11903175
  • 539 積分球式反射型パルスオキシメータの研究(GS-14 診断・治療,一般セッション,学術講演)
    瀧川 隆介; 尹 娜; 角田 直人; 山田 幸生; 木村 利久; 青木 一男
    一般社団法人日本機械学会, 出版日 2006年01月12日, バイオエンジニアリング講演会講演論文集, 2005巻, 18号, 掲載ページ 377-378, 日本語, 110006205609, AA11903175
  • 分子イメージングにおける光学技術への期待
    山田幸生
    出版日 2006年, 光学, 35巻, 2号, 掲載ページ 65, 日本語, 記事・総説・解説・論説等(その他)
  • A154 蛍光画像解析法による血液製剤混入白血球の計数(OS-17 バイオ・メディカルテクノロジーにおける熱工学の進展II)
    廣野 泰亮; 薮崎 克己; 山田 幸生
    Fluorescence image was investigated for development of a leukocyte counter for quality assurance tests of transfusion blood products. The standard leukocyte fluorescence image profile was established by averaging the actual fluorescence image of leukocytes. It was used for development of an optimum image analysis algorithm to avoid miss-counting of the dust contaminated from the environment. The centrifugal concentration process was investigated by a computer simulation, and it was found that this process caused leukocyte overlapping and limited the measurement range. We succeed in developing the leukocyte counter, with improving the accuracy and the measurement range up to 25 [WBC/μl]., 一般社団法人日本機械学会, 出版日 2005年11月02日, 熱工学コンファレンス講演論文集, 2005巻, 掲載ページ 35-36, 日本語, 110006206637, AA11901963
  • A141 近赤外光を用いた生体計測とイメージング(基調講演,OS-17 バイオ・メディカルテクノロジーにおける熱工学の進展I)
    山田 幸生
    This review introduces the recent developments in the field of biomedical measurement and imaging using near infra-red light, including pulse oximeter, oxygen monitor, optical mapping (topography), diffuse optical tomography, retinal imaging, and fluorescence tomography., 一般社団法人日本機械学会, 出版日 2005年11月02日, 熱工学コンファレンス講演論文集, 2005巻, 掲載ページ 23-24, 日本語, 110006206631, AA11901963
  • (1)Anatomical and Functional Images of in vitro and in vivo Tissues by NIR Time-domain Diffuse Optical Tomography(論文,日本機械学会賞〔2004年度(平成16年度)審査経過報告〕)
    趙 会娟; 高 峰; 谷川 ゆかり; 本間 一弘; 小野寺 陽一; 山田 幸生
    一般社団法人日本機械学会, 出版日 2005年05月05日, 日本機械学會誌, 108巻, 1038号, 掲載ページ 345-345, 日本語, 0021-4728, 110006218925, AN00187394
  • Time-resolved diffuse optical tomographic imaging for providing both anatomical and functional information of biological tissue
    ZHAO Huijuan; ZHAO Huijuan; GAO Feng; GAO Feng; TANIKAWA Yukari; HOMMA Kazuhiro; YAMADA Yukio
    出版日 2005年, APPLIED OPTICS, 44巻, 10号, 掲載ページ 1905-1916, 0003-6935, 80017827745, 15813527
  • 光伝播の時間分解計測に基づく拡散光トモグラフィの開発
    山田幸生
    出版日 2005年, 熱物性, 19巻, 6号, 掲載ページ 103-108, 日本語, 記事・総説・解説・論説等(その他)
  • 光学的血糖値測定手法開発の現状と実現へのとりくみ
    垂水正敏; 島田光功; 有本英伸; 丸尾勝彦; 山田幸生
    出版日 2005年, ライフサポート, 17巻, 1号, 掲載ページ 3-8, 日本語, 記事・総説・解説・論説等(その他)
  • 時間分解計測法による拡散光トモグラフィ
    山田幸生
    出版日 2005年, 日本レーザー医学会誌, 26巻, 3号, 掲載ページ 214-221, 日本語, 記事・総説・解説・論説等(その他)
  • 時間分解測定法による層構造光散乱媒体の下層の吸収係数決定法(オーガナイズドセッション13 バイオシステムにおける熱・物質移動)
    佐藤 知絵; 島田 美帆; 山田 幸生; 星 詳子
    We propose a new method to determ ine the absorption coefficient (μ_a) of the lower layer in a two-layered medium using time-resolved spectroscopy (TRS). To estimate the variation of μ_a with the depth, the difference in the temporal profiles of light attenuation between a two-layered medium and a homogeneous one was divided into time segments, and a slope of each segment was calculated to get the time-segmented μ_a of the layered medium. Its validity was examined both by a Monte Carlo simulation and phantom experiments. The results suggest the possi bility that μ_a of hum an cerebral tissue can be selectively determined by TRS., 一般社団法人日本機械学会, 出版日 2004年11月10日, 熱工学コンファレンス講演論文集, 2004巻, 掲載ページ 393-394, 日本語, 110004058065, AA11901963
  • Simple algorithm to estimate the absorption coefficients of two-layered scattering media from the spatially- and time-resolved reflectance
    Miho Shimada; Yukio Yamada; Yoko Hoshi
    A time-resolved diffuse reflectance from a semi-infinite homogeneous medium is compressed along the time axis and multiplied by appropriate factors. According to the photon diffusion equation, a gradient of the attenuation difference between the compressed reflectance and that measured with a smaller source-detector distance is proportional to the absorption coefficient. Using this property, a simple algorithm using spatially and time-resolved reflectance to measure the absorption coefficient of a homogeneous medium is proposed as an alternative to the procedure of fitting to the photon diffusion equation. In the case of a two-layered medium, the absorption coefficient of each layer can be estimated also using this simple algorithm if approximate values of the depth of the upper layer and the scattering coefficients of the two layers are known beforehand. For validation experiment, the time-resolved reflectance from a polyacetal block was measured at various source-detector distances and the estimated absorption coefficient of the block was compared to that obtained using the conventional method. As the result of in vivo experiment, the absorption coefficient of the lower layer of a human head was found to be larger than that of the upper layer under the assumption that the human head consisted of two layers., 出版日 2004年10月27日, Proceedings of SPIE - The International Society for Optical Engineering, 5321巻, 掲載ページ 138-148, 0277-786X, 5644265080
  • 体表温の正規化への試み : 異なる温熱環境下における体表温の比較評価のための正規化された体表温指標作成の試み
    角田 直人; 山田 幸生; 横山 真太郎; 満渕 邦彦
    出版日 2004年06月07日, Biomedical thermology : the journal of the Japanese Society of Thermorogy = 医学・生物学サーモロジー, 24巻, 1号, 掲載ページ 11-11, 日本語, 0916-6238, 10013438573, AN10339852
  • 2003年光学界の進展 17.医学・生物応用光学
    山田幸生
    出版日 2004年04月, 光学, 33巻, 掲載ページ 227-228, 日本語, 記事・総説・解説・論説等(その他)
  • 拡散光イメージングによる脳機能計測
    山田幸生
    出版日 2004年02月, 光学, 33巻, 掲載ページ 103-109, 日本語, 記事・総説・解説・論説等(その他)
  • 人工膵臓用超微量流量計の研究開発
    西山尚; 小西 義昭; 村上 元章; 藤原 真人; 角田 直人; 山田 幸生
    一般社団法人日本機械学会, 出版日 2004年, 日本機械学会第16回バイオエンジニアリング講演会講演論文集2004, 掲載ページ 207-208, 日本語, 110002484165, AA11903175
  • 拡散光を用いた生体組織のイメージング:最近の成果と動向
    山田幸生
    日本オプトメカトロニクス協会, 出版日 2004年, 光技術コンタクト, 42巻, 7号, 掲載ページ 359-369, 日本語, 記事・総説・解説・論説等(その他), 0913-7289, 40006353509, AN10075091
  • H143 光利用と生体
    山田 幸生
    This paper reviews the current status and future prospects of optical technologies using near-infrared light for biology and medicine. Light in the near-infrared wavelength range has higher transmittance through biological tissues, and is frequently used for measuring physiological information such as tissue oxygenation, hemodynamics, and concentrations of tissue fluids. However, light in the near-infrared wavelength range is subject not only to the absorption but also to the strong scattering by tissues. Due to this strong scattering of light by tissue light propagates diffusely in tissues. This paper focuses on the technologies of diffuse optical imaging and noninvasive measurement of blood glucose level., 一般社団法人日本機械学会, 出版日 2003年11月10日, 熱工学コンファレンス講演論文集, 2003巻, 掲載ページ 329-330, 日本語, 110002489708, AA11901963
  • 3次元光CTを応用した低侵襲的脳腫瘍摘出法の開発
    酒谷 薫; 山田 幸生; 片山 容一
    出版日 2003年09月28日, 日本レーザー医学会誌 = The Journal of Japan Society for Laser Medicine, 24巻, 3号, 掲載ページ 201-201, 日本語, 0288-6200, 10012435520, AN0035795X
  • B209 生体組織の光学特性測定
    岡田 賢二; 間下 友加里; 飯野 賢治; 桃木 秀幸; 角田 直人; 山田 幸生
    一般社団法人日本機械学会, 出版日 2003年09月17日, バイオフロンティア講演会講演論文集, 2003巻, 14号, 掲載ページ 135-136, 日本語, 1348-2939, 110002479253, AA11902434
  • 光学的血糖値測定の数値シミュレーションと誤差低減法
    山田幸生; 垂水正敏
    日本医療機器学会, 出版日 2003年08月, 医科器械学, 73巻, 8号, 掲載ページ 415-421, 日本語, 記事・総説・解説・論説等(その他), 0385-440X, 110002514935, AN00013123
  • 【体内植え込み型インスリン注入システムの開発動向】光学的血糖値測定システムの開発状況
    丸尾 勝彦; 鶴来 充啓; 清崎 若正; 太田 智浩; 有本 英伸; 山田 幸生; 田村 守; 石井 正孝; 尾崎 幸洋
    (一社)日本医療機器学会, 出版日 2003年08月, 医科器械学, 73巻, 8号, 掲載ページ 406-414, 日本語, 記事・総説・解説・論説等(その他), 0385-440X, 2004016859
  • 拡散光トモグラフィ(光CT)の研究開発
    山田幸生
    出版日 2003年08月, BME(日本エム・イー学会雑誌), 17巻, 4号, 掲載ページ 35-43, 日本語, 記事・総説・解説・論説等(その他)
  • Noninvasive blood glucose monitoring using near-infrared dermis tissue spectra
    K Maruo; M Tsurugi; J Chin; T Ota; H Arimoto; Y Yamada; M Tamura; M Ishii; Y Ozaki
    AMER DIABETES ASSOC, 出版日 2003年06月, DIABETES, 52巻, 掲載ページ A435-A435, 英語, 研究発表ペーパー・要旨(国際会議), 0012-1797, WOS:000183173801871
  • 226 細胞熱計測のための微小熱電対プローブの開発
    角田 直人; 鈴木 隆文; 齋藤 敬; 満渕 邦彦; 山田 幸生
    一般社団法人日本機械学会, 出版日 2003年01月20日, バイオエンジニアリング講演会講演論文集, 2003巻, 15号, 掲載ページ 239-240, 日本語, 110002483968, AA11903175
  • 503 生体光伝播シミュレーションのための光学特性値測定
    太田 智浩; 垂水 正敏; 有本 英伸; 島田 美帆; 山田 幸生
    一般社団法人日本機械学会, 出版日 2003年01月20日, バイオエンジニアリング講演会講演論文集, 2003巻, 15号, 掲載ページ 123-124, 日本語, 110002483910, AA11903175
  • 逆問題解法による拡散光断層イメージング
    山田幸生; 高 峰
    出版日 2002年11月, レーザー研究, 30巻, 11号, 掲載ページ 625-629, 日本語, 記事・総説・解説・論説等(その他)
  • 脳機能の光計測
    山田幸生
    レ-ザ-学会, 出版日 2002年11月, レーザー研究, 30巻, 11号, 掲載ページ 623-624, 日本語, 記事・総説・解説・論説等(その他), 0387-0200, 40005496807, AN00255326
  • A Monte Carlo simulation of NIR spectrum changes induced by variations of glucose concentration
    Masatoshi Tarumi; Mitsunori Shimada; Tomoya Murakami; Mamoru Tamura; Miho Shimada; Yukio Yamada
    We have analyzed the light propagation in tissue simulating media by a Monte Carlo method, using the estimated changes in the optical properties caused by variation of glucose concentration and temperature of the media. Using the calculated data, we have predicted the changes in the absorbance spectra caused by the change in glucose concentration in the absorbing and scattering medium. The predicted spectra have agreed very well with those obtained by the experiments. We have also studied the effects of the varying scattering coefficient on the spectra, and found that the changes in the absolute value and the wavelength dependency of the scattering coefficient are closely related to the changes in the observed spectra. In addition, we have calculated the changes in the absorbance spectra, when the glucose concentration and the temperature of glucose solution vary simultaneously. Using the multivariate analysis, we have extracted the glucose concentration accurately from the calculated absorbance spectra. © 2002 SPIE., 出版日 2002年05月24日, Proceedings of SPIE - The International Society for Optical Engineering, 4624巻, 掲載ページ 28-35, 0277-786X, 10012675552, 0036057207
  • 2426 近赤外光イメージングシステムによるヒト頭部の DPF 測定
    谷川 ゆかり; 趙 会娟; SASSAROLI Angelo; 高 峰; 小野寺 陽一; 山田 幸生
    一般社団法人日本機械学会, 出版日 2002年03月01日, バイオエンジニアリング講演会講演論文集, 2002巻, 14号, 掲載ページ 335-336, 日本語, 110002483841, AA11903175
  • 脳組織モデルを用いたマルチスペクトル画像の重回帰分析
    横山健太郎; 本庄一史; 渡辺基志; 牧敦; 山田幸生; 伊関洋; 岡田英史
    出版日 2002年, 応用物理学関係連合講演会講演予稿集, 49th巻, 3号, 200902163922755041
  • バイオエンジニアリングにおける伝熱研究の進展
    山田幸生
    日本伝熱学会, 出版日 2002年01月, 伝熱, 41巻, 166号, 掲載ページ 3-8, 日本語, 記事・総説・解説・論説等(その他), 1344-8692, 10010165832, AA11315621
  • 光CTの原理と現状・将来
    山田幸生
    出版日 2001年04月, 精密工学会誌, 67巻, 4号, 掲載ページ 541-545, 日本語, 記事・総説・解説・論説等(その他)
  • 官から見た産学官連携のあり方
    山田 幸生
    出版日 2001年03月01日, 伝熱研究 = News of HTSJ, 40巻, 161号, 掲載ページ 13-14, 日本語, 0910-7851, 10017034832, AN0015409X
  • 336 一様および層状媒体の光学的拡散係数の測定法
    Martelli Fabrizio; Angelo Sassaroli; 山田 幸生; Giovanni Zaccanti
    一般社団法人日本機械学会, 出版日 2001年01月15日, バイオエンジニアリング講演会講演論文集, 2001巻, 13号, 掲載ページ 256-257, 英語, 110002483654, AA11903175
  • 光と生体
    山田幸生
    共立出版, 出版日 2001年, 光による医学診断, 掲載ページ 19-36, 20001543260
  • 脳へら型組織酸素モニタリングプローブの試作
    小野寺 陽一; 山田 幸生; 酒谷 薫; 堀 智勝
    出版日 2000年12月30日, Journal of Japan Society of Computer Aided Surgery : J.JSCAS, 2巻, 3号, 掲載ページ 145-146, 日本語, 1344-9486, 10024482515, AA11908088
  • 423 光を用いた脳マッピング画像の再構成法
    小田 一郎; 綱澤 義夫; 山田 幸生
    一般社団法人日本機械学会, 出版日 2000年11月27日, 計算力学講演会講演論文集, 2000巻, 13号, 掲載ページ 411-412, 日本語, 1348-026X, 110002487088, AA1190257X
  • 近赤外光による生体機能計測と光CT
    山田幸生; 田村守; 綱澤義夫; 土屋裕
    出版日 2000年04月, 計測と制御(自動制御学会誌), 39巻, 4号, 掲載ページ 239-245, 日本語, 記事・総説・解説・論説等(その他)
  • Fundamental studies of photon migration in biological tissues and their application to optical tomography
    Yukio Yamada
    This paper reviews the studies of photon migration in biological tissues and its application to optical tomography which were conducted in the Mechanical Engineering Laboratory of Japan's Ministry of International Trade and Industry. The research subjects range from theoretical and experimental studies of photon migration in random media to the development of image reconstruction algorithms and experiments for optical tomography. The most fundamental theoretical study of the photon diffusion equation has proved that the photon diffusion coefficient is independent of the absorption coefficient while the conventional one is dependent on the absorption coefficient. Experimental studies included the time-resolved spectroscopy and the fabrication of realistic human head phantoms which have five tissue types with different optical properties. Several types of reconstruction algorithms have been developed and verified experimentally. These investigations are pioneering work in the field of biomedical optics in Japan., Optical Society of Japan, 出版日 2000年, Optical Review, 7巻, 5号, 掲載ページ 366-374, 英語, 査読付, 記事・総説・解説・論説等(その他), 1340-6000, 0034346609
  • 生体熱工学の現状と展望
    山田幸生
    一般社団法人日本機械学会, 出版日 1999年11月, 日本機械学会熱工学部門ニュースレター,日本機械学会誌, 102巻, 972号, 掲載ページ 701-709, 日本語, 記事・総説・解説・論説等(その他), 0021-4728, 110002439198, AN00187394
  • 光断層イメージングシステム---ナショナルプロジェクトの成果---
    山田幸生
    出版日 1999年11月, 日本機械学会誌,トピックス欄, 102巻, 972号, 掲載ページ 692, 日本語, 記事・総説・解説・論説等(その他)
  • ダイナミック部分を持つヒト頭部光学ファントムの作製
    今井 大吾; 谷川 ゆかり; 山田 幸生
    工業技術院機械技術研究所, 出版日 1999年05月, 機械技術研究所所報, 53巻, 3号, 掲載ページ 72-81, 日本語, 0388-4252, 40000578879, AN00048977
  • 体内を透視する光断層イメージング
    山田幸生
    The Japan Institute of Metals and Materials, 出版日 1999年03月, まてりあ, 38巻, 3号, 掲載ページ 189-193, 日本語, 記事・総説・解説・論説等(その他), 1340-2625, 130004352079
  • 低温やけどについて
    山田幸生
    出版日 1999年03月, 製品と安全, 72号, 掲載ページ 2-8, 日本語, 記事・総説・解説・論説等(その他)
  • 光トポグラフィの画像作成アルゴリズム評価
    山本剛; 牧敦; 谷川ゆかり; 山下優一; 山田幸生; 小泉英明
    出版日 1999年, 応用物理学会学術講演会講演予稿集, 60th巻, 3号, 200902187801685557
  • 酸素状態の断層像を描き出す光CT
    山田幸生
    医歯薬出版, 出版日 1998年08月, 医学のあゆみ, 186巻, 5号, 掲載ページ 335-340, 日本語, 記事・総説・解説・論説等(その他), 0039-2359, 40000112772, AN10289798
  • 光で体の中を視る―光CTによる生体診断ー
    山田 幸生
    一般社団法人日本機械学会, 出版日 1998年07月05日, 日本機械学会誌, 101巻, 956号, 掲載ページ 529-533, 日本語, 0021-4728, 110002438586, AN00187394
  • 光で体の中を視る 光CTによる生体診断
    山田幸生
    出版日 1998年07月, 日本機械学会誌, 101巻, 956号, 掲載ページ 29-33, 日本語, 記事・総説・解説・論説等(その他)
  • 散乱性媒質中の放射エネルギーの伝搬と生体医用光学
    山田 幸生; 高橋 修一; 谷川 ゆかり
    応用物理学会分科会日本光学会, 出版日 1997年12月10日, 光学, 26巻, 12号, 掲載ページ 649-656, 日本語, 0389-6625, 10016237046, AN00080324
  • 光散乱媒体内における極短パルス光伝ぱのモデルと解析
    KUMAR Sunil; MITRA Kunal; VEDAVARZ Ali; 山田 幸生
    Light pulses have found increasing use in medicine and biology. Biological tissues, however, scatter light very strongly, and the modeling of light pulse propagation in biological tissues has not been established because of scattering. We compare the results of three modeling methods, the photon diffusion approximation, the diffusive wave approximation, and the two-flux method with those of the discrete ordinate method which provides the exact solution of the transient equation of radiative transfer for the case of 1 picosecond pulse incidence on scattering and absorbing slab or semi-infinite media simulating biological tissues. The early behavior of the light pulses predicted by the photon diffusion approximation is quite different from that by the diffusive wave approximation. In the later period both the photon diffusion and diffusive wave approximations are able to give reasonable results, but the two-flux method is not. Because of much shorter computation time, the diffusive wave approximation is advantageous to the photon diffusion approximation., 一般社団法人日本機械学会, 出版日 1997年03月25日, 日本機械学会論文集. C編, 63巻, 607号, 掲載ページ 895-900, 日本語, 0387-5024, 110002385017, AN00187463
  • 光学的ファントムの作製と積分球による光学定数測定
    水野 祥; 谷川 ゆかり; 山田 幸生; 牧 博司
    Noninvasive diagnosis by near-infrared light is widely used because it can provide physiological information about biological tissues. For quantitative measurement, however, estimation of the optical properties of biological tissues is necessary with respect to understanding of photon migration in media which scatter light strongly. The purpose of this study is to fabricate stable, solid phantoms which optically simulate biological tissues, and to measure their optical properties using an integrating sphere and a Monte Carlo simulation. The solid phantoms were fabricated using either polyester or epoxy resin as the base material, and small titanium oxide particles were mixed to provide appropriate scattering of light. Their optical properties were measured by means of spectroscopy using an integrating sphere and numerical simulation using a Monte Carlo method. The reduced scattering coefficients were measured within an uncertainty of approximately 4% and ranged from 0.3 to 1.5 mm^<-1>, which are typical values of biological tissues in the near-infrared wavelength range. The measured absorption coefficients of the phantoms were below 0.0034 mm^<-1>, which are satisfactorily small values., 一般社団法人日本機械学会, 出版日 1997年03月25日, 日本機械学会論文集. C編, 63巻, 607号, 掲載ページ 889-894, 日本語, 0387-5024, 110002385016, AN00187463
  • ズーミング法を用いた逆問題解法による光断層イメージング
    Jones Matthew R.; Proskurin Sergei G.; 谷川 ゆかり; 山田 幸生
    日本エム・イー学会, 出版日 1997年03月10日, 医用電子と生体工学 : 日本ME学会雑誌 = Japanese journal of medical electronics and biological engineering : JJME, 35巻, 1号, 掲載ページ 55-63, 日本語, 0021-3292, 10009790925, AN00016981
  • 強い散乱体の光CTシミュレ-ション-2-ファンビ-ム方式
    山田 幸生; 長谷川 裕夫
    Optical-CT (Computed Tomography) imaging of living bodies poses the difficulty caused by strong scattering of light by tissues. In our previous paper, time-resolved spectroscopy was shown to have potential for realization of optical-CT imaging. In this second paper, it is shown that utilization of the characteristics of strong scattering makes fan-beam-type optical-CT imaging possible. The Monte Carlo method is employed to simulate the strongly scattering and weakly absorbing media. Hybrid scattering calculation is proposed to simulate the highly forward-directed scattering to avoid unrealistic sharp peaks at the shortest time of flight observed when only isotropic scattering approximation is employed. The temporally extrapolated absorbance method is employed for the object and reference cylinder, as in the previous paper. Fan-beam-type optical-CT imaging is numerically shown to be capable of reconstructing an image of the difference in the absorption coefficient with satisfactory accuracy and spatial resolution., 一般社団法人日本機械学会, 出版日 1993年05月, 日本機械学会論文集 B編, 59巻, 561号, 掲載ページ p1766-1769, 日本語, 0387-5016, 110002392032, AN00187441
  • 光断層イメ-ジングのシミュレ-ション (バイオ特集)
    山田 幸生; 長谷川 裕夫
    工業技術院機械技術研究所, 出版日 1991年09月, 機械技術研究所所報, 45巻, 5号, 掲載ページ p219-224, 日本語, 0388-4252, 40000578766, AN00048977
  • 強い散乱体の光CTシミュレ-ション
    山田 幸生; 長谷川 裕夫
    Computed tomography (CT) essentially assumes that rays such as X-rays propagate straight within the body ; therefore, it is difficult to apply this assumption to bodies which scatter the incident rays. Since the living tissues are very strong light-scattering media, realization of optical-CT scanners is not considered easy, although it is highly desired because of its possible ability to measure the oxygenation states in the body with a noninvasive method. This report shows how optical-CT imaging is possible by the use of time-resolved spectroscopy. The object is a cylindrical scattering medium containing a coaxial small cylinder with both scattering and absorption, while the reference is only the scattering cylinder. The light transmission data are generated by the Monte Carlo method. The temporal variations of the difference in the optical density between the object and reference provide the projection data necessary for the CT reconstruction procedure. The obtained image reflects the profile of the difference in the absorption coefficient between the object and the reference with satisfactory accuracy and spacial resolution., 一般社団法人日本機械学会, 出版日 1991年08月, 日本機械学会論文集 B編, 57巻, 540号, 掲載ページ p2822-2825, 日本語, 0387-5016, 110002402429, AN00187441
  • セラミックガスタ-ビンの研究開発 (新しいエンジン技術<今月のテ-マ>)
    山田 幸生
    一般社団法人日本機械学会, 出版日 1990年02月, 日本機械学会誌, 93巻, 855号, 掲載ページ p129-135, 日本語, 0021-4728, 110002436754, AN00187394

書籍等出版物

  • より良いfNIRS(機能的近赤外分光法)計測のために
    山田幸生ほか
    その他, 日本語, 共著, 日本光脳機能イメージング学会, 出版日 2017年03月
  • 医用画像解析ハンドブック
    山田幸生
    学術書, 日本語, 分担執筆, 4.6.1 近赤外光, オーム社, 出版日 2012年11月
  • 医用画像工学ハンドブック
    山田幸生
    学術書, 日本語, 分担執筆, Part I 第2章 6.4拡散光イメージング, 日本医用画像工学会, 出版日 2012年09月
  • シミュレーション辞典
    山田幸生; 大川晋平
    日本語, 共著, 蛍光トモグラフィー, コロナ社, 出版日 2012年02月
  • NIRS---基礎と臨床
    山田幸生
    日本語, 共著, 第I章A-5 拡散光トモグラフィー, 新興医学出版社, 出版日 2012年01月
  • 伝熱工学資料 改訂第5版
    山田幸生
    日本語, 共著, 6・5・5 生体のふく射, 日本機械学会, 出版日 2009年05月
  • 機械工学便覧
    山田幸生
    日本語, 共著, 応用システム編 γ9 医療・福祉・バイオ機器,「4・11 その他の映像検査装置 4・11・1 CT」, 日本機械学会, 出版日 2008年08月
  • 非侵襲・可視化技術ハンドブック
    山田幸生
    日本語, 共著, 第3章第1節3.多重散乱系での光伝播に関する光学特性値と基礎方程式,第3章第3節3.2光拡散方程式に基づく拡散光トモグラフィ,第3章第4節3.小動物の蛍光イメージングおよび生物発光イメージング, (株)エヌ・ティー・エス, 出版日 2007年06月
  • 糖尿病学の進歩(第41集)
    田村 守; 丸尾勝彦; 山田幸生
    日本語, 共著, 非観血的血糖計測装置, (株)診断と治療社, 出版日 2007年03月
  • エレクトロニクス分野における熱制御,放熱・冷却技術
    石塚勝; 渡辺聡志監修
    日本語, 共著, 第4章第5節[1]低温やけどのメカニズム, 技術情報協会, 出版日 2006年10月
  • レーザーハンドブック第2版
    山田幸生
    日本語, 共著, IX編バイオフォトニクス,38章臨床診断,38・2 拡散光トモグラフィ, オーム社, 出版日 2005年04月
  • 表面・界面工学大系
    角田直人; 山田幸生
    日本語, 共著, 上巻基礎編 第20章第6節「温度の測定」, フジテクノシステム, 出版日 2005年03月
  • 大森豊明監修,「生体物理刺激と生体反応」の分担執筆:第1編第11章「熱」,pp. 158-166,第2編第11章「熱による生体への影響」,pp. 323-330,第3編第13章「熱の医療応用」pp. 547-555
    山田幸生
    日本語, 共著, 第1編第11章「熱」,第2編第11章「熱による生体への影響」,第3編第13章「熱の医療応用」, フジテクノシステム, 出版日 2004年01月
  • 先端放射医療技術と計測(電気学会放射波の医療応用と計測技術調査専門委員会編)中,7.1節「近赤外光による計測とイメージング」
    山田幸生
    日本語, 共著, コロナ社,2001年11月15日, 出版日 2001年11月
  • 光による医学診断(田村 守編著)中,1-1節「光と生体---生体分光学への招待」)
    山田幸生
    日本語, 共著, 共立出版,平成13年3月30日, 出版日 2001年03月
  • 田村 守編著,「光による医学診断」,山田幸生分担執筆:1-1節「光と生体---生体分光学への招待」
    山田幸生
    日本語, 共著, 共立出版, 出版日 2001年03月
  • メディカルエンジニアリング(立石哲也編著)中,2-3節「光による生体診断」,3-2節「レーザ治療」
    山田幸生
    日本語, 共著, 米田出版,2000年4月5日, 出版日 2000年04月
  • からだと熱と流れの科学(山田幸生編著)中,「はじめに」,3章「身体の中の良い熱・悪い熱」,6章「レーザの光と熱を用いる診断・医療技術」
    山田幸生
    日本語, 編者(編著者), オーム社,1998年10月30日, 出版日 1998年10月

講演・口頭発表等

  • 近赤外光による生体センシング--パルスオキシメータから拡散光トモグラフィまで--
    山田幸生
    口頭発表(招待・特別), 日本語, 第24回 酸素ダイナミクス研究会, 招待, 国内会議
    発表日 2020年10月10日
  • 分光学的視点から見た非侵襲血糖測定技術
    丸尾勝彦; 山田幸生
    その他, 日本語, 日本学術振興会第185委員会2019年度第1回研究会, 日本学術振興会第185委員会, 東京都千代田区, 国内会議
    発表日 2019年06月17日
  • Numerical treatment of highly forward-directed scattering on radiative transfer using the delta-m approximation and galerkin quadrature method
    Hiroyuki Fujii; Go Chiba; Yukio Yamada; Yoko Hoshi; Kazumichi Kobayashi; Masao Watanabe
    口頭発表(一般), 英語, The 9th International Symposium on Radiative Transfer (RAD-19), ICHMT, Athens, Greece, 国際会議
    発表日 2019年06月03日
  • 近赤外分光による非侵襲血糖測定‐分光学的視点から見た非侵襲血糖測定技術‐
    丸尾勝彦; 山田幸生
    口頭発表(招待・特別), 日本語, 2019年度日本分光学会年次講演会, 招待, 日本分光学会, 京都府宇治市, 国内会議
    発表日 2019年05月14日
  • 蛍光食品を利用した誤嚥検査法および水の近赤外光吸収スペクトルを利用した温度・濃度変化のイメージング
    山田幸生
    その他, 日本語, 日本学術振興会第185委員会2018年度第3回研究会, 招待, 日本学術振興会第185委員会, 東京都千代田区, 国内会議
    発表日 2019年02月28日
  • Near-infrared spectroscopic method for noninvasive blood glucose prediction without using multivariate analyses
    K. Maruo; Y. Yamada
    ポスター発表, 英語, 78th Scientific Sessions of American Diabetes Association, American Diabetes Association, Orlando, Florida, USA, 国際会議
    発表日 2018年06月22日
  • Aspiration Risk Detection Using Oral Administration of Fluorescent Food --- Preliminary Experiments Using Meat Phantoms ---
    Takahiro SUZUKI; Ryohei SAITO; Nobuo KITADA; Takuji KOIKE; Shojiro MAKI; Yukihiro MICHIWAKI; Goro NISHIMURA; Haruki NIWA; Yukio YAMADA
    口頭発表(一般), 英語, 2017 IEEE International Conference on Cyborg and Bionic Systems (CBS 2017), IEEE, Beijing, China, 国際会議
    発表日 2017年10月17日
  • Recent Progresses of DOT and Blood Glucose Measurement
    山田幸生
    公開講演,セミナー,チュートリアル,講習,講義等, 英語, Special talk at College of Precision Instrument and Optoelectronics Engineering, Tianjin University, 招待, College of Precision Instrument and Optoelectronics Engineering, Tianjin University, Tianjin, China, 国際会議
    発表日 2017年05月30日
  • Non-invasive near-infrared blood glucose measurement: two new approaches
    Yukio Yamada
    シンポジウム・ワークショップパネル(指名), 英語, Samsung Future Tech Forum, 招待, Samsung Future Technology Research Center, Suwan, Korea, 国際会議
    発表日 2016年10月25日
  • 生体内光伝播と生体内熱移動 ― 光温熱療法に向けて ―
    山田幸生
    公開講演,セミナー,チュートリアル,講習,講義等, 日本語, 第47回BASIC(分野横断型医工学研究プラットフォーム)講演会, 招待, ASIC(分野横断型医工学研究プラットフォーム), 東京, 国内会議
    発表日 2016年08月24日
  • Numerical modeling of photon migration in the cerebral cortex of the living rat using the radiative transport equation
    Hiroyuki Fujii; Shinpei Okawa; Ken Nadamoto; Eiji Okada; Yukio Yamada; Yoko Hoshi; Masao Watanabe
    口頭発表(一般), 英語, SPIE BiOS 2015, SPIE, San Francisco, USA, 国際会議
    発表日 2015年02月07日
  • 生体光イメージングのためのヒト頸部内光伝播モデルの構築
    藤井宏之; 大川晋平; 灘本健; 岡田英史; 山田幸生; 星詳子; 渡部正夫
    口頭発表(一般), 日本語, 日本機械学会第27回バイオエンジニアリング講演会, 日本機械学会, 新潟市, 国内会議
    発表日 2015年01月09日
  • 近赤外吸収イメージング法を応用したマイクロ流路内の酸塩基中和反応の可視化
    川嶋大介; 角田直人; 近藤克哉; 有本英伸; 山田幸生
    口頭発表(一般), 日本語, 第30回近赤外フォーラム, 近赤外分光研究会, つくば市, 国内会議
    発表日 2014年11月27日
  • Numerical modeling of photon migration in human thyroid based on the radiative transport equation
    H. Fujii; S. Okawa; K. Nadamoto; E. Okada; Y. Yamada; Y. Hoshi; M. Watanabe
    シンポジウム・ワークショップパネル(公募), 英語, The 3rd International Conference on Complex Dynamical Systems & Their Applications, Ankara, Turkey, 国際会議
    発表日 2014年11月24日
  • 生体医用光学の発展と産学連携および将来
    山田幸生
    公開講演,セミナー,チュートリアル,講習,講義等, 日本語, 第6回 BioOpto Japanカンファレンス, 招待, BioOpto Japan, 横浜市, 国内会議
    発表日 2014年10月15日
  • 時間分解スペクトロスコピー(TRS)の基礎
    山田幸生
    公開講演,セミナー,チュートリアル,講習,講義等, 日本語, 次世代NIRS「時間分解スペクトロスコピー(TRS)」セミナー, 招待, 日本大学工学部 次世代工学技術研究センター, 福島県郡山市, 国内会議
    発表日 2014年09月28日
  • 近赤外吸収イメージング法を応用した高周波磁場下における磁性微小球周りの水の温度分布推定
    山田健太; 角田直人; 藤岡良太; 近藤克哉; 有本英伸; 山田幸生
    口頭発表(一般), 日本語, 第51回日本伝熱シンポジウム, 日本伝熱学会, 浜松市, 国内会議
    発表日 2014年05月21日
  • 近赤外域の2波長を用いたマイクロ流路内の酸・アルカリ水溶液混合場の濃度イメージング
    川嶋大介; 角田直人; 近藤克哉; 有本英伸; 山田幸生
    口頭発表(一般), 日本語, 第51回日本伝熱シンポジウム, 日本伝熱学会, 浜松市, 国内会議
    発表日 2014年05月21日
  • 近赤外分光法と拡散光トモグラフィー・蛍光トモグラフィー
    山田幸生
    シンポジウム・ワークショップパネル(指名), 日本語, 京都大学数理解析研究所研究集会「偏微分方程式に対する逆問題の数学解析と数値解析」, 招待, 京都大学数理解析研究所, 京都市, 国内会議
    発表日 2013年07月16日
  • 近赤外光法と拡散光トモグラフィー・蛍光トモグラフィー
    山田幸生
    シンポジウム・ワークショップパネル(指名), 日本語, 自然科学研究機構 画像逆問題の数理解析研究会 第二回研究会, 招待, 自然科学研究機構, 東京都千代田区, 国内会議
    発表日 2012年12月21日
  • 近赤外分光法による生体計測とイメージング・医学応用
    山田幸生
    シンポジウム・ワークショップパネル(指名), 日本語, 放射線医学総合研究所セミナー, 招待, 放射線医学総合研究所, 千葉市, 国内会議
    発表日 2012年09月18日
  • 近赤外光を用いた生体計測技術の新展開
    山田幸生
    シンポジウム・ワークショップパネル(公募), 日本語, 東北大学GCOEプログラム「流動ダイナミクスと医療の融合」ワークショップ, 東北大学
    発表日 2011年02月
  • 生体熱工学と低温熱傷について
    山田幸生
    口頭発表(招待・特別), 日本語, 病院環境設備研究会講演会, 病院環境設備研究会
    発表日 2010年12月
  • 拡散光トモグラフィーとその展開について
    山田幸生; 大川晋平
    口頭発表(招待・特別), 日本語, 日本光学会 光設計研究グループ第45回研究会「生体イメージングの新しい展開」, 日本光学会
    発表日 2010年11月
  • 拡散光トモグラフィーおよび蛍光トモグラフィーによる生体情報の断層画像化について
    山田幸生
    口頭発表(招待・特別), 日本語, 第14回酸素ダイナミクス研究会, 酸素ダイナミクス研究会
    発表日 2010年09月
  • 時間分解計測と拡散方程式を用いた拡散光トモグラフィーの現状
    山田幸生
    口頭発表(招待・特別), 日本語, 研究集会「偏微分方程式の逆問題解析とその周辺分野に関する研究」, 京都大学数理解析研究所
    発表日 2010年06月
  • 大学が育成を目指す伝熱人材像
    山田幸生
    その他, 日本語, 第47回日本伝熱シンポジウム 産学連携フォーラム, 社)日本伝熱学会
    発表日 2010年05月
  • Some topics in biomedical optics --- Toward collaboration between China and Japan
    Y. Yamada
    その他, 英語, Seminar at College of Precision Instrument and Optoelectronics Engineering, Tianjin University
    発表日 2010年04月
  • 拡散光を用いた生体医用光学
    山田幸生
    その他, 日本語, 第10回連携創造本部先端研究推進部門『ナノ・フォトニクス技術セミナー』, 神戸大学
    発表日 2010年01月
  • 蛍光トモグラフィーにおける画像化技術
    山田幸生
    その他, 日本語, 大学知財群活用セミナー, 経済産業省 関東経済産業局
    発表日 2010年01月
  • Diffuse Light Spectroscopy and Imaging for Biomedical Engineering
    Y. Yamada
    口頭発表(招待・特別), 英語, Workshop on Information, Nano and Photonics Technology 2009, Kobe University, Kobe, Japan, 国際会議
    発表日 2009年12月
  • Physical fundamentals of optical mapping and diffuse optical tomography using NIRS
    Yukio Yamada
    口頭発表(招待・特別), 英語, The 36th Annual Conference of International Society of Oxygen Transport to Tissue (ISOTT2008), International Society of Oxygen Transport to Tissue, Sapporo, Japan, 国際会議
    発表日 2008年08月
  • Optical brain imaging in infants by use of near-infrared diffuse optical tomography
    T. Kusaka; S. Okawa; M. Ueno; R. Fukuzawa; T. Nishida; K. Isobe; Y. Tanikawa; F. Gao; C. Sato; Y. Hoshi; Y. Yamada
    口頭発表(一般), 英語, The 36th Annual Conference of International Society of Oxygen Transport to Tissue (ISOTT2008)
    発表日 2008年08月
  • Physical fundamentals of optical mapping and diffuse optical tomography using NIRS
    Yukio Yamada
    口頭発表(招待・特別), 英語, The 36th Annual Conference of International Society of Oxygen Transport to Tissue (ISOTT2008), International Society of Oxygen Transport to Tissue, Sapporo, Japan, 国際会議
    発表日 2008年08月
  • 光脳機能イメージングの原理
    山田幸生
    口頭発表(招待・特別), 日本語, 第9回日本光脳機能イメージング研究会, 日本光脳機能イメージング研究会
    発表日 2008年07月
  • “医療及び健康・福祉分野を支える光技術と将来展望に関する調査研究報告書”,「第II章 第5節 拡散光トモグラフィー」,「第IV章 第1節 血糖値センサー(1)」
    山田幸生
    その他, 日本語, 医療及び健康・福祉分野を支える光技術と将来展望に関する調査研究委員会,(社)日本オプトメカトロニクス協会,医療及び健康・福祉分野を支える光技術と将来展望に関する調査研究委員会報告
    発表日 2008年03月
  • New methodology of optical blood glucose monitoring based on simulation of light propagation in the skin
    Yukio Yamada; Katsuhiko Maruo; Hidenobu Arimoto; Mamoru Tamura; Yukihiro Ozaki
    口頭発表(招待・特別), 英語, Optical Imaging 2006 at NIH --- Fifth Inter-Institute Workshop on Optical Diagnostic Imaging from Bench to Bedside at the National Institutes of Health ---, NIH (National Institute of Health), Bethesda, Maryland, USA, 国際会議
    発表日 2007年09月
  • 文部科学省科学技術・学術審議会資源調査分科会報告“光資源を活用し,創造する科学技術の振興~持続可能な「光の世紀」に向けて~,「第3章3.光を用いた非侵襲生体診断」
    山田幸生
    その他, 日本語, 文部科学省科学技術・学術審議会資源調査分科会,文部科学省科学技術・学術審議会資源調査分科会報告書
    発表日 2007年09月
  • 皮膚などの光散乱体中の光伝搬シミュレーション
    山田幸生
    口頭発表(招待・特別), 日本語, 第22回近赤外フォーラム, 近赤外研究会
    発表日 2006年11月
  • New methodology of optical blood glucose monitoring based on simulation of light propagation in the skin
    Yukio Yamada; Katsuhiko Maruo; Hidenobu Arimoto; Mamoru Tamura; Yukihiro Ozaki
    口頭発表(招待・特別), 英語, Optical Imaging 2006 at NIH --- Fifth Inter-Institute Workshop on Optical Diagnostic Imaging from Bench to Bedside, National Institutes of Health, USA, Bethesda, USA, 国際会議
    発表日 2006年09月
  • 近赤外光を用いた生体計測とイメージング
    山田幸生
    口頭発表(一般), 日本語, 日本機械学会,熱工学コンファレンス2005
    発表日 2005年11月
  • 近赤外光を用いた生体計測とイメージング
    山田幸生
    口頭発表(一般), 日本語, 日本機械学会,熱工学コンファレンス2005, 日本機械学会, 国内会議
    発表日 2005年11月
  • 分光技術による眼底の機能情報イメージングと課題
    山田幸生
    口頭発表(一般), 日本語, NEDOワークショップ「人体の“窓”,眼底から体内を見る(診る)」
    発表日 2005年04月
  • バイオエンジニアリングにおける熱工学の現状と将来
    山田幸生
    口頭発表(一般), 日本語, 日本機械学会,2004日本機械学会年次大会
    発表日 2004年09月
  • PHOTON MIGRATION IN BIOLOGICAL TISSUES AND DIFFUSE OPTICAL IMAGING
    Yukio Yamada
    口頭発表(招待・特別), 英語, Saratov Fall Meeting SFM’04, Saratov, Russia, 国際会議
    発表日 2004年09月
  • 生体医用光学の最近の動向
    山田幸生
    口頭発表(一般), 日本語, 社)日本オプトメカトロニクス協会,光センシング技術部会
    発表日 2004年07月
  • Photon migration in tissues, diffuse optical imaging and their applications to biomedicine
    Y. Yamada; F. Gao; H. Zhao; Y. Tanikawa; K. Homma
    口頭発表(招待・特別), 英語, ICO’04 (2004 ICO International Conference Optics & Photonics in Technology Frontier, Chiba, Japan, 国際会議
    発表日 2004年07月
  • 時間分解法による拡散光断層イメージングの現状と展望
    山田幸生
    口頭発表(一般), 日本語, 第1回光脳機能イメージング研究会
    発表日 2004年03月
  • 拡散光トモグラフィとその可能性
    山田幸生; 高 峰; 趙 会娟; 谷川ゆかり; 本間一弘
    口頭発表(一般), 日本語, レーザー学会,レーザー学会学術講演会第24回年次大会
    発表日 2004年01月
  • 拡散光トモグラフィとその可能性
    山田幸生; 高 峰; 趙 会娟; 谷川ゆかり; 本間一弘
    口頭発表(招待・特別), 日本語, レーザー学会学術講演会第24回年次大会, レーザー学会
    発表日 2004年01月
  • Photon migration in biological tissue and application to diffuse optical tomography
    Y. Yamada
    口頭発表(招待・特別), 英語, The 5th Pacific Rim Conference on Lasers and Electro-Optics, Taipei, Taiwan, 国際会議
    発表日 2003年12月
  • 生体内熱輸送および光伝播とイメージング
    山田幸生
    口頭発表(一般), 日本語, 日本機械学会,日本機械学会熱工学部門特別企画「熱工学の新領域に関するセミナー」
    発表日 2003年11月
  • Optical transport process in turbid media and applications to optical imaging of tissues
    Y. Yamada
    口頭発表(招待・特別), 英語, XI Conference on Laser Optics, Pertersburg, Russia, 国際会議
    発表日 2003年06月
  • NIRSイメージング:トモグラフィによる定量化の実現
    山田幸生; 高 峰; 趙 会娟; 谷川ゆかり
    口頭発表(一般), 日本語, ヒト脳機能マッピング学会,第5回ヒト脳機能マッピング学会大会, 第5回ヒト脳機能マッピング学会大会
    発表日 2003年03月
  • NIRSイメージング:トモグラフィによる定量化の実現
    山田幸生; 高 峰; 趙 会娟; 谷川ゆかり
    口頭発表(一般), 日本語, ヒト脳機能マッピング学会,第5回ヒト脳機能マッピング学会大会
    発表日 2003年03月
  • LIGHT PROPAGATION IN BIOLOGICAL TISSUES AND OPTICAL DIAGNOSTICS BY IMAGING AND SPECTROSCOPY
    Yukio Yamada
    口頭発表(招待・特別), 英語, ICBME 2002 (International Congress on Biological and Medical Engineering 2002), 招待, ICBME 2002 (International Congress on Biological and Medical Engineering 2002), 国際会議
    発表日 2002年12月
  • LIGHT PROPAGATION IN BIOLOGICAL TISSUES AND OPTICAL DIAGNOSTICS BY IMAGING AND SPECTROSCOPY
    Yukio Yamada
    口頭発表(招待・特別), 英語, ICBME 2002 (International Congress on Biological and Medical Engineering 2002), 国際会議
    発表日 2002年12月
  • Optical imaging using time-resolved measurements
    Y. Yamada; F. Gao; H. Zhao; Y. Tanikawa; Y. Onodera; A. Sassaroli
    口頭発表(招待・特別), 英語, PIERS (Progress In Electromagnetics Research Symposium) 2002, PIERS (Progress In Electromagnetics Research Symposium), 国際会議
    発表日 2002年07月
  • Optical Topography --- Visualization of Brain Activation by Near-Infrared Spectroscopy
    T. Yamamoto; A. Maki; Y. Tanikawa; M. Kiguchi; E. Okada; Y. Yamada; H. Koizumi
    口頭発表(招待・特別), 英語, PIERS (Progress In Electromagnetics Research Symposium) 2002, PIERS (Progress In Electromagnetics Research Symposium), 国際会議
    発表日 2002年07月
  • Biomedical optical imaging by a time-resolved multichannel system
    Y. Yamada
    口頭発表(招待・特別), 英語, Joint Symposium on Bio-Sensing and Bio-Imaging, Joint Symposium on Bio-Sensing and Bio-Imaging, Yamagata, Japan, 国際会議
    発表日 2001年08月02日
  • Photon migration in biological tissues, their optical properties and imaging
    Y. Yamada; A. Sassaroli; F. Martelli; F. Gao; H. Zhao; Y. Onodera; Y. Tanikawa; K. Tanaka; R. Araki
    口頭発表(招待・特別), 英語, CLEO/Pacific Rim 2001, Special Session: Spectroscopy and Imaging for Brain and Characterization of Tissues, CLEO/Pacific Rim 2001, Chiba, Japan, 国際会議
    発表日 2001年07月15日
  • Photon migration in biological tissues, their optical properties and imaging
    Y. Yamada; A. Sassaroli; F. Martelli; F. Gao; H. Zhao; Y. Onodera; Y. Tanikawa; K. Tanaka; R. Araki
    口頭発表(招待・特別), 英語, Technical Digest of CLEO/Pacific Rim 2001, Special Session: Spectroscopy and Imaging for Brain and Characterization of Tissues, Chiba, Japan, 15-19 July, 2001, 国際会議
    発表日 2001年07月
  • Measurement of optical properties of brain in vivo
    Y. Yamada; A. Sassaroli; Y. Tanikawa; F. Martelli; R. Arakai; K. Tanaka
    口頭発表(招待・特別), 英語, Pacifichem 2000, Symposium No. 75, Frontiers of Spectroscopic Analysis of the Brain, Pacifichem 2000, Honolulu, USA, 国際会議
    発表日 2000年12月14日
  • Performance of a Multi-Channel Time-Resolved Optical Tomographic Imaging System and Tomographic Images
    Y. Yamada; M Tamura; H. Eda; I. Oda; Y. Ito; Y. Wada; Y. Oikawa; Y. Tsunazawa; M. Takada; Y. Tsuchiya; Y. Yamashita; M. Oda; A. Sassaroli
    口頭発表(招待・特別), 英語, Proceedings of Inter-Institute Workshop on In Vivo Optical Imaging at the NIH (National Institutes of Health), Ed. A. H. Gandjbakhche, OSA, 国際会議
    発表日 2000年
  • Performance of a Multi-Channel Time-Resolved Optical Tomographic Imaging System and Tomographic Images
    Y. Yamada; M Tamura; H. Eda; I. Oda; Y. Ito; Y. Wada; Y. Oikawa; Y. Tsunazawa; M. Takada; Y. Tsuchiya; Y. Yamashita; M. Oda; A. Sassaroli
    口頭発表(招待・特別), 英語, Inter-Institute Workshop on In Vivo Optical Imaging at the NIH, National Institutes of Health, Bethesda, Maryland, USA, 国際会議
    発表日 1999年09月16日
  • Performance of a Multi-Channel Time-Resolved Optical Tomographic Imaging System and Tomographic Images
    Y. Yamada
    口頭発表(一般), 英語, Inter-Institute Workshop on In Vivo Optical Imaging at the NIH (National Institutes of Health), Bethesda, Maryland, USA, (Sep. 16-17, 1999)
    発表日 1999年09月

所属学協会

  • 米国光工学会
  • 応用物理学会
  • 日本機械学会
  • 日本伝熱学会
  • 日本生体医工学会
  • 米国光学会
  • 英国物理学会
  • 日本光学会
  • 電気学会
  • 日本光脳機能イメージング研究会

共同研究・競争的資金等の研究課題

  • 蛍光食品を用いた非侵襲誤嚥検査法の研究開発
    山田幸生
    研究期間 2018年07月01日 - 2021年03月31日
  • 近赤外温度・濃度同時イメージング法によるマイクロ反応拡散場の直接定量評価
    角田 直人; 有本 英伸; 近藤 克哉; 山田 幸生
    日本学術振興会, 科学研究費助成事業, 首都大学東京, 基盤研究(B), 水の近赤外吸収バンドの分光特性に基づき開発した温度・濃度同時イメージング法により、マイクロ流路内の各種水溶液の反応拡散現象を可視化した。水溶液間に形成される界面において、拡散に伴う濃度の時空間変化を測定し、拡散係数を算出した。同時に、拡散係数の温度依存性を定量的に明らかにした。酸、アルカリ水溶液については、中和反応に伴う各反応物と生成塩の濃度の画像化に成功した。また、液液界面の不安定性について分析し、拡散および化学反応が不安定化の開始時間に影響を与えることを明らかにした。以上の成果より、本イメージング法の有用性が実証され、従来難しかった反応拡散場の可視定量分析が可能となった。, 26289049
    研究期間 2014年04月01日 - 2017年03月31日
  • 数値解析・応用数学的アプローチによる高解像光トモグラフィ実現のための基礎研究
    磯 祐介
    研究期間 2013年04月01日 - 2016年03月31日
  • 近赤外温度イメージング法によるマイクロ化学チップ内の発熱反応測定
    角田 直人; 有本 英伸; 近藤 克哉; 山田 幸生
    日本学術振興会, 科学研究費助成事業, 基盤研究(B), マイクロ流路内における水溶液の温度と濃度を同時にイメージングできるシステムを開発した。測定原理は近赤外域の水の吸収スペクトルの温度依存性を応用しており、温度感度波長(1412 nmもしくは1905 nm)と非温度依存性の等吸収点(1442 nmもしくは1935 nm)の吸光度画像を各100 frames/sで交互取得できるシステムである。マイクロ流路に異なる温度と濃度のエタノール水溶液を流した場合の画像を取得し、両波長の画像を用いて温度分布と濃度分布を画像化できることを示し、本システムの有効性を確認した。中和反応実験では酸とアルカリ水溶液の反応前後での濃度変化を画像化することに成功した。, 23360102
    研究期間 2011年04月01日 - 2014年03月31日
  • ソース推定逆問題解法を用いた光イメージングによる乳がん検診
    大川 晋平; 山田 幸生
    日本学術振興会, 科学研究費助成事業, 電気通信大学, 若手研究(B), 生体透過性の高い近赤外光を用いて,生体内の断層画像を取得する拡散光/蛍光トモグラフィ技術に関して,乳がん診断への応用に向けて,拡散光トモグラフィを行う際の効率的な照射・検出器配置を検討した.また,がん組織などを標識した生体内の蛍光物質の分布や光の伝播にかかわる生体内の光学特性値分布を推定する空間フィルタによる逆問題解法と,時間分解計測データからノイズを除去する,事後確率最大化推定を用いた信号処理アルゴリズムを提案し,シミュレーションと生体模擬試料を用いた実験でそれらの有効性を示した., 21760312
    研究期間 2009年 - 2010年
  • 針型マイクロプローブへのDLCコーティング技術の開発とその応用
    奥山 直樹; 角田 直人; 山田 幸生
    日本学術振興会, 科学研究費助成事業, 電気通信大学, 萌芽研究, 高周波プラズマCVD装置をベースとした、針型マイクロプローブへのDLC成膜装置の改良と、高電圧パルス成膜法の有効性を検討した。昨年度までに開発した成膜装置は、成膜対象の針型プローブ(先鋭部径1μm、直径1mm、高さ50mm)自体をカソード電極とし、このカソード電極を中心に、ステンレスメッシュ製の円筒形電極(直径40mm、高さ50mm)をアノード電極(グランド)とした電極構造を有する。アノード内のプローブ周囲に比較的均一なプラズマの発生が可能であったが、特に先端部のDLC膜が変質する場合が観察されたため、印加電圧の制御方法について改良を実施した。具体的には、先端部は過度なイオン衝突による温度上昇が発生しやすいため、放電・冷却サイクルのパラメータを変更し、膜質との関係を検証した。絶縁破壊電圧が-400V、放電維持電圧が-120V、放電時間が5s以下、冷却時間が45s以上で膜の剥離や変性がほとんど起きないことを確かめた。本年度後半からは、さらなる膜厚化と多数プローブの同時成膜を目的として、3極構造とした高電圧パルス成膜を実施した。平行平板間でプラズマを発生させ(バイアス電圧-350V)、プラズマ中に第3の電極となるプローブを挿入し、これに高電圧パルス(-800V;10μs,100Hz)を付加した。安定した成膜が可能であり、1hの成膜時間で1μm以上の膜厚がプローブ全体で得られた。堆積した膜は水素を多く含有する重合膜に近いものであったが、高電圧パルスのパラメータを変更することで膜質の変更が可能であり、用途に応じた成膜を多数本のプローブに対して行える基盤技術を提供できたといえる。, 16651078
    研究期間 2004年 - 2005年
  • 生体細胞内操作用超小型ナノ作業ロボットの開発
    青山 尚之; 山田 幸生; 岩田 太
    日本学術振興会, 科学研究費助成事業, 電気通信大学, 基盤研究(B), 本課題ではナノメートルの位置決め分解能を有する超小型ロボットにより細胞内に極細ガラスプローブを精密に穿刺し,細胞内の生体素子や核移植を可能にすることを最終目的としている.次の段階では蛍光顕微鏡により,生体内の代謝反応やタンパク質の流動などをリアルタイムで計測し、同時に超小型ロボットに搭載した極細計測プローブをナノオーダで操作し、一連の細胞処理システムの構築を実現する. 本年度は下記の成果が得られた。 ・ナノ精度を有する超小型移動機構と細胞の非接触マニピュレーション法の検討 顕微鏡視野内では細胞操作のために、それを搭載する超小型ロボットには平面内の精密並進だけでなく、回転も必要である.そこで圧電素子4個とコの字型電磁石で構成されるインチォーム式の超小型移動機構の開発成功し、顕微鏡焦点の周りに精密に自在に移動させることができた.またこの機構に搭載した極細ガラスプローブを振動させて、その先端近傍に流れる微小流動を利用して、細胞を搬送し、また回転位置決めできることを明らかにした. ・局所熱流動検出方法 細胞レベルでの温度変化を測定するための微小熱電対プローブを作製した。プローブはガラスマイクロピペットをベースとし、Ni、電機絶縁膜、コンスタンタンと順に薄膜を積層させ、先端部でNiとコンスタンタンを接合させる構造とした。特に、このような薄膜層構造では、均質な絶縁膜の形成が重要であるため、ここではDLC膜を選択し、プラズマCVD法によりコーティングする手法を開発した。先端部の金属接合部の作製にはFIBを用いた。次に、プローブの熱電性能を評価し、培養細胞を対象とした温度測定システムをセットアップした。今後、測定システムのノイズ対策・信号処理の改善と、数多くの細胞測定によるデータ収集を実施した。 ・極細プローブによる加工法 SPM用の探針を積極的に応用し、表面の微細な加工法について検討を行った.その結果、先端の液滴をフェムトリットルの分解能で付着させたり、これと紫外線硬化樹脂を組み合わせて微小立体を形成させたりすることに成功している.さらに金属粒子を付着させたDNAの観察にも成功しており、生体内素子の観察の可能性を高めた., 15360134
    研究期間 2003年 - 2005年
  • 生命系のホメオスタシスを構築するトランスファロームのシステム生物学
    谷下 一夫; 山田 幸生; 石黒 博; 高松 洋; 白樫 了; 小林 弘祐
    日本学術振興会, 科学研究費助成事業, 慶應義塾大学, 基盤研究(C), 生命システムは、呼吸循環系と代謝系を中心に、熱と物質の移動を極めて精密かつ緻密に制御し、深部温度を一定に保つことができ、さらに広範囲な分子量にわたる物質の移動を制御することによって、エネルギ代謝を行い、生命活動の原動力になっている。従って、生命システムは熱と物質移動の宝庫とも言うべきものであるが、従来は局所的な熱と物質移動の取り扱いがされているだけで、生命システム全体で、熱と物質移動現象が、生命システムの動的恒常性であるホメオスタシスを実現しているかが不明であった。生命システムの熱と物質移動現象は、生命活動に直接関わっているため、生命システム全体の熱と物質移動が明らかになることによって、医学における診断・治療や薬物輸送の薬理効果が明らかになり、革新的な医学が出現する可能性がある。生命システムにおける熱と物質移動の総体を、ここでトランスファロームと名づけ、これまでのシステム生物学では重点的に取り上げられていなかった熱と物質移動のダイナミクスをトランスファロームで明らかにすることを目標としている。そこで、まず本企画調査では、生命システムにおける熱と物質移動現象に関して、移動現象論、医学生物学および薬理学の立場から調査・討論を行い、トランスファロームのシステム生物学を確立するための研究計画をたてた。具体的には、5回の研究会(シンポジウムを2回)、幹事会を2回開催し、研究計画の独自性、ニーズ、特徴、社会への波及効果などを中心に議論を行った。その結果、十分に特定研究のテーマとして相応しいという結論に達し、今後特定研究の具体的な申請の手続きを行うこととした。, 16636004
    研究期間 2004年 - 2004年

産業財産権

  • 検出装置、検出方法、及び検出器
    特許権, 山田幸生, 西村吾朗, 丹羽治樹, 牧昌次郎, 道脇幸博, 小池卓二, 鈴木祟弘, 田代剛大, 特願2019-132298, 出願日: 2019年07月17日, 電気通信大学,北海道大学,昭和大学
  • 光断層像の生成法
    特許権, 山田幸生, 大川晋平, 山本拓明, 2009-020330, 出願日: 2009年11月30日, (株)富士フィルム, 特開2010-1754, 公開日: 2010年01月30日, 第5283525号, 発行日: 2013年06月07日
  • 計測対象保持具,生体保持具及び光計測装置
    特許権, 山田幸生, 清水仁, 木村壮士, 特願2009-020331, 出願日: 2009年11月30日, (株)富士フィルム, 特開2010-197381, 公開日: 2010年09月09日, 第5274492号, 発行日: 2013年05月24日
  • マイクロ化学チップ装置
    特許権, 山田幸生, 角田直人, 廣野泰亮, 2006-142214, 出願日: 2006年05月23日, 特開2007-315753, 公開日: 2007年12月06日, 第4915690号, 発行日: 2012年02月03日
  • 光学的成分測定方法および装置
    特許権, 垂水正敏, 山田幸生, 特願2001-167339号, 特願2001-228507号, 出願日: 2001年07月27日, (株)日機装,(独)産業技術総合研究所, 特開2003-50200号, 公開日: 2003年02月21日, 第4633302号, 発行日: 2010年11月26日
  • 流量測定方法およびそれに用いる測定装置
    特許権, 山田幸生, 桃木秀幸, 角田直人, 2003-042619, 2004-043386, 出願日: 2004年02月19日, (株)キャンパスクリエイト, 2004-271523, 公開日: 2004年09月30日, 第4565233号, 発行日: 2010年08月13日
  • 光プローブ,これを用いた計測システム,および,これを用いた反射光検出方法
    特許権, 山田幸生, 角田直人, 青木一男, 木村利久, 2003-118301, 2004-128918, 出願日: 2004年04月23日, (株)オータックス,(株)キャンパスクリエイト, 2004-337605, 公開日: 2004年12月02日, 第4551998号, 発行日: 2010年07月23日
  • 粒子計測装置、及び粒径計測装置
    特許権, 山田幸生, 大川晋平, 廣野泰亮, 12/595,348, 電気通信大学,興和(株), US2010/0110177A1, 公開日: 2010年05月06日
  • 流量測定装置及び流量測定方法
    特許権, 濱崎英司, 山田幸生, 大川晋平, 正本和人, 白石 和, 2010-81438, 出願日: 2010年03月31日, 電気通信大学,(株)東京計装
  • マイクロ化学チップ装置
    特許権, 廣野泰亮, 山田幸生, 大川晋平, 2008-197679, 出願日: 2008年07月31日, 電気通信大学,(株)興和, 2010-32472, 公開日: 2010年02月12日
  • 計測対象保持具
    特許権, 山田幸生, 清水仁, 2009-020331, 出願日: 2009年11月30日, 電気通信大学,(株)富士フィルム
  • 光学的血糖値測定用ピックアップ
    特許権, 丸尾勝彦, 鶴来充啓, 中川武大, 山田幸生, 2003-313164, 出願日: 2003年09月04日, (株)パナソニック電工, 第4363130号, 発行日: 2009年08月28日
  • MICRO CHIP DEVICE
    特許権, Yukio Yamada, Naoto Kakuta, Taisuke Hirono, 11/751,793, 出願日: 2007年05月22日, US 2008/0056953 A1, 公開日: 2008年03月06日, US 7,553,454 B2, 発行日: 2009年06月30日
  • 血小板凝集反応評価方法,及び血小板凝集反応評価装置
    特許権, 山田幸生, 大川晋平, 廣野泰亮, 2008-090211, 出願日: 2008年03月31日, 電気通信大学,(株)興和, 2009-244053
  • 光学的散乱特性推定装置およびその作動方法
    特許権, 垂水正敏, 山田幸生, 有本英伸, 2002-302287, 出願日: 2002年10月16日, 日機装,産業技術総合研究所, 2004-138454, 公開日: 2004年05月13日, 第3902999号, 発行日: 2007年01月12日
  • 樹脂製マイクロ流体チップの溶着方法
    特許権, 黒﨑晏夫, 山田幸生, 大川晋平, 清水直紀, 2006-312841, 出願日: 2006年11月20日
  • 目的物質の塗布方法,及びマイクロ化学チップ
    特許権, 山田幸生, 角田直人, 廣野泰亮, 2006-142215, 出願日: 2006年05月23日
  • 非接触温度測定装置
    特許権, 山田幸生, 角田直人, 李 富国, 2005-243214, 出願日: 2005年08月24日
  • マイクロプローブ並びにその製造装置及び方法
    特許権, 角田直人, 奥山直樹, 渡邊まゆ, 山田幸生, 2005-041142, 出願日: 2005年02月17日
  • 温度測定方法およびそれに用いる測定装置
    特許権, 山田幸生, 桃木秀幸, 角田直人, 2003-042620, 出願日: 2003年02月20日, 2004-251766, 公開日: 2004年09月09日
  • Optical phantom of Living Body and Method for Producing It(生体の光学ファントム及びその製造法(日本の特許を米国でも取得))
    特許権, Yukio Yamada, Yukari Tanikawa, Shuichi Takhashi, Daigo Imai, 09/145227, 出願日: 1998年09月01日, 6083008, 発行日: 2004年07月04日
  • 生体組織モニタリング用プローブ付きへら
    特許権, 山田幸生, 小野寺陽一, 酒谷 薫, 堀 智勝, 特願2000-71711, 出願日: 2000年03月15日, 3502902, 発行日: 2003年12月19日
  • 散乱物体の光学定数決定法
    特許権, 山田幸生, 荒木隆一郎, 山下 豊, 平7-300464, 出願日: 1995年10月26日, 3401376, 発行日: 2003年02月21日
  • 生体の光学ファントム作製法(注目発明選定:科学技術庁長官(2000年4月18日))
    特許権, 山田幸生, 谷川ゆかり, 鎮西清行, 高橋修一, 今井大吾, 平9-38513, 出願日: 1997年02月06日, 2857753, 発行日: 1998年12月04日
  • 光CT装置(注目発明選定:科学技術庁長官(1993年4月12日)).
    特許権, 山田幸生, 長谷川裕夫, 平2-279942, 出願日: 1991年10月18日, 1841512, 発行日: 1994年05月12日