KATO Yuji Hokkaido Univ., Grad.Sch.of Eng., Lecturer, 大学院・工学研究科, 助手 (50261582)
YAMAMOTO Katsuyuki Hokkaido Univ., Grad.Sch.of Eng., Professor, 大学院・工学研究科, 教授 (10088867)
SHIMIZU Koichi Hokkaido Univ., Grad.Sch.of Eng., Professor, 大学院・工学研究科, 教授 (30125322)
FUKUSHIMA Kikuro Hokkaido Univ., Sch.of Medicine, Professor, 大学院・医学研究科, 教授 (70091486)
With a view toward the realization of an optical CT, this study was conducted to develop an advanced measurement technique to obtain physiological information using multi wavelength and ultra-short pulse of light. Through this study, the following results were obtained.
1) A principle to suppress the strong scattering in biological tissue was developed. With this principle, we can detect a weak near-axis scattered component of light which is usually buried in a strong scattered component.
2) A time-resolved measurement technique with an ultra-short pulse was applied to the detection of the near-axis scattered light. A technique to obtain the integral of absorption along the optical axis of the incident beam of light was developed.
3) An experimental system was developed to use the above technique. In the experiment with this system, the absorption distribution in a scattering medium was obtained. With this technique, the spatial resolution of the reconstructed image was improved significa
ntly. In addition, the quantitative measurement of absorption distribution became possible, which had been difficult without this technique.
4) A principle of cross-sectional imaging using backscattered light was newly developed for the body part in which transmitted light could not be detected. To utilize this principle, a measurement technique was developed. In a simulation study, the effectiveness and the property of this technique were clarified.
5) An experimental system was developed to use this technique. The absorption distribution in a model phantom of biological tissue was reconstructed. As a result, the reconstructed image agreed well qualitatively with the given distribution. However, further improvement was required for the quantitative measurement. It was also found that the effect of measurement error was not negligible. A new reconstruction algorithm was developed to overcome these problems by the use of multi-wavelength and ultra-short pulse of light. In the simulation and experiment, the effectiveness of this new technique was verified. Less