Abstract
Measurement of blood perfusion is a valuable medical diagnostics because changes in blood perfusion are an important indicationof a variety of pathological processes. Thus blood perfusion is an important component of normal tissue physiology and it also contributes to the heat transfer of the body. Loading a thermal stimulus in a local area of skin, the temperature response at the skin surface depends on the amount of blood perfusion. This implies that the volume of blood perfusion could be evaluated by the temperature response. According to this principle, we have formulated simple bio-heat transfer model for a local area of skin in a cylindrical coordinate system and developed the parameter estimation method by applying inverse analysis. Unknown parameters are blood perfusion, thermal conductivity and total heat transfer coefficient. As the result of numerical experiment we found that there was the strong linear relationship between the preset blood perfusion and the estimated blood perfusion. And the results of the experiment using phantom tissue which mimics blood perfusion supported the results of numerical experiment. Blood perfusion can be calibrated by using this phantom tissue. Also we demonstrated that there was the linear relationship between the measured value of “Laser Doppler flow meter” and the estimated blood perfusion from the practical experiment. These results show the validity of our methodology. In addition, both measurement repeatability and sensitivity have been improved by more than three times using the newly developed cylindrical heat source as the thermal stimulus instead of the conventional point heat source.
