Sensitivities of Spatial-resolved Diffuse Reflectance for Biological Tissue to First-order Parameters

The sensitivity expressions of spatial-resolved diffuse reflectance to first-order parameters are derived in the P3 approximation of transport theory. The influence of first-order scattering parameter and absorption parameter on the P3 approximation are analysed, it is demonstrated that the sensitivity of absorption parameter is positive for the whole range from the source to the detector, and the slope of it with low absorption is larger than that of high absorption; The sensitivity of first-order scattering parameter is negative for close to the source, positive for far from the source, zero for about a distance–where the change of first-order scattering parameter influence on reflectance is the weakest, the change of reflectance comes from the change of absorption, we can obtain absorption information with measuring diffuse reflectance at the distance. The distance of the sensitivity to first-order scattering parameter equaling zero is found shortened when a medium has higher scattering coefficient.