用蒙特卡罗方法模拟光在多层组织中的吸收特性

Monte Carlo Study of Light Absorption Feature in Multi-Layered Tissue

在讨论目前新颖的组织功能成像的可能性 (例如光声成像 )时 ,光子在组织中的吸收和散射特性是一个很重要的问题。鉴于这一点 ,本文利用一个多层模型研究了光子在皮肤、脂肪和肌肉组织中的吸收和散射特性 ,得到了在组织中某一深度处光子在一个平面上的吸收分布 ,以及在不同吸收系数和散射系数的情况下 ,光子的反射、吸收和透射几率。结果表明在经过多次散射后 ,大部分的光子被吸收 ,在本文的模型中只有 7.3%的光子从表面反射 (包括镜面反射和漫反射 )。还讨论了不同光学参数对能流分布的影响。

The features of photon absorption and scattering in tissues are very important issue to the discussion of the feasibility of some novel optical methods for tissue functional imaging,such as photo-acoustic imaging.Under this background,in this paper,a multi-layered model was used to simulate the absorption and scattering features of light in skin,adipose and muscle. The light was perpendicularly incident on the top surface of the model tissue. The absorption distribution was obtained on a plane at a certain depth into tissue. The probability of reflectance,absorption and transmission of photons are discussed with the changing of optical parameters of the tissue. The results showed that most of the photons are absorbed after multi-layered tissue scatterings with about 7.3 percent reflectance(specular reflectance and diffuse reflectance) from epidermis. The fluence rate is also discussed at different values of absorption and scattering coefficients.