A novel approach has been proved to quickly and non-invasively determine the optical properties of human skin in vivo. It is based on the diffuse reflectance approximation model and subjected to the well established library of absorption spectra of water and hemoglobin. Under the nonlinear least-square algorithm, fitting the measured spectra in the range of 400--1000 nm to the diffusion approximation model, the reduced scattering coefficient and absorption coefficient of skin tissue can be quickly determined in vivo. The results show that this method is convenient and suitable for the real-time clinical application.
To confirm the existence and properties of human meridians, the optical transport properties along the pericardium meridian and tissues around the pericardium meridian are studied noninvasively on twenty healthy volunteers in vivo and then compared with each other. Our study shows that the light propagating along the meridian and non-meridian directions both conform to the Beer＇s exponential attenuation law. However, statistical analysis of the results suggests that the optical transport properties of human meridian differ from those of the surrounding tissues over a low modulated frequency range （P 〈 0.01）, and light attenuation along the pericardium meridian is significantly less than that along the non-meridian direction. These findings not only indicate the existence of acupuncture meridian from the point of view of biomedical optics, but also shed new light on an approach to investigation of human meridians.
