各向异性生物组织中偏振光传输的模拟与实验

Simulation and Experiment of Polarized Light Propagating in Anisotropic Tissue

针对具有纤维状结构特征的生物组织(诸如肌肉、皮肤等),建立了包含球状散射体和具有取向分布的圆柱状散射体的仿体模型,并对偏振光在这类具有各向异性分布的复杂体系中的传输过程进行了蒙特卡罗模拟。给出了蒙特卡罗模拟程序的实现方法并验证了程序的可靠性,随后将程序用于模拟和分析一些肌肉组织的偏振成像实验。实验和模拟结果的一致性验证了用柱-球散射体混合的仿体模型来模拟各向异性生物组织的合理性。同时,通过模拟验证,得到了两个新的参量,分别可以用来表征组织样品中纤维的空间取向和组织样品的各向异性度。

The propagation of polarized light in anisotropic medium like some fibrous tissues （e. g., muscle, skin, tooth） is investigated with Monte Carlo method. In the simulation, the myofibrils and collagen fibers are approximated as long cylinders and the tissue phantom is composed of spherical and cylindrical structures. We present the realization and validation of Monte Carlo program, and then apply the program to simulate and analyze polarization imaging process of muscle. The good agreement between the simulation results and the experimental results validates the assumption of the phantom composition and shows the feasibility of Monte Carlo method. This paper also presents how to describe tissue anisotropy according to two parameters derived from the polarization imaging.