Study on the backscattering Mueller matrix of the sphere-cylinder scattering model of anisotropic tissues

摘要

Most biological tissues are anisotropic turbid media containing fibrous structures, such as collagen fibers, axons, or myofibrils. Tests using both unpolarized and polarized lights indicate that the anisotropic tissues can be approximated to a scattering medium containing cylindrical and spherical scatterers. Mueller matrix, as a representative measurement to examine polarization properties, can be used to analyze some important information of turbid media. In this paper, we measure the two dimensional backscattering Mueller matrix of a microsphere-silk phantom composed of a slab of well aligned silk fibers submerged in microsphere solution. We also use a polarization sensitive Monte Carlo simulation program to analyze the Mueller matrix of sphere-cylinder scattering media, such as the microsphere-silk sample. We present systematic analysis about the relationship between the characteristic features in all the Mueller matrix elements and the important parameters of the sphere-cylinder scattering medium approximating biological tissues, such as the sphere-cylinder ratio, direction of the cylinders, diameters of both types of scatterers, etc. These experimental and simulation results confirm the practicability of backscattered Mueller matrix characterizing such anisotropic scattering media like biological tissues.