| Project/Area Number |
11558100
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 展開研究 |
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| Research Field |
Biomedical engineering/Biological material science
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| Research Institution | HOKKAIDO UNIVERSITY |
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Principal Investigator |
YAMAMOTO Katsuyuki Hokkaido Univ., Grad. School of Eng., Prof., 大学院・工学研究科, 教授 (10088867)
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| Co-Investigator(Kenkyū-buntansha) |
HAMAOKA Takafumi Tokyo Medical College, School of Med., Lect., 医学部, 講師 (70266518)
KAWAHATSU Kiyonori Hokkaido Univ., Physical Education Center, Asso. Prof., 体育指導センター, 助教授 (80026822)
KUDO Nobuki Hokkaido Univ., Grad. School of Eng., Inst., 大学院・工学研究科, 助手 (30271638)
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| Project Period (FY) |
1999 – 2001
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| Keywords | near-infrared light / tissue oxygen monitor / muscle / adipose tissue / Monte Carlo simulation / optical properties of tissues / optical imaging |
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| Research Abstract |
The objectives of this study were to develop a tissue oxygen monitor that can eliminate the influence of a fat layer on muscle oxygenation measurement using near-infrared spectroscopy (NIRS) and to establish quantitative NIRS by verifying the validity of this technique in the field of sports medicine.
1. Mean optical properties (absorption and scattering coefficients) of muscle and adipose tissues were determined by comparing results of in vivo measurements using time-resolved NIRS with those of Monte Carlo simulation using a multi-layered model.
2. A nonlinear algorithm for tissue oxygenation measurement was theoretically derived, based on diffusion theory, and the coefficients of the algorithm were determined from the mean optical properties of muscles.
3. A correction method for eliminating the great influence of a fat layer on measurement sensitivity was developed so that the theoretical algorithm assuming a homogeneous medium could be applied. Validity of this correction method was also confirmed by magnetic resonance spectroscopy.
4. As an application of NIRS to exercise physiology, restoration rates of muscle oxygenation after exercise n were measured in 13 top athletes of National Team for Nordic skiing during high-altitude training. It was found that the restoration rates increased by 11 % and 20 % at 6 and 11 days after the beginning of the training, respectively.
5. New measurement techniques for estimating muscle metabolism were developed: oxygen saturation of blood in muscles and oxygen consumption of muscles were estimated from change in blood volume and from a decreasing rate of muscle oxygenation, respectively, during contraction.
6. A 200-channel imaging system of muscle oxygenation was developed: and spatio-temporal changes in oxy- and deoxy-hemoglobin during knee extension and flexion were successfully imaged on the thigh.
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