生物组织光传输的几何推导求解模型

Solution Model of Light Diffusion in Bio-tissues Based on Geometry Deduction

受到光束扩散模型和漫射近似理论的启发,提出了一种改进的光传输求解模型。这个新的几何推导模型采用了光束扩散的思想,但是光束扩散不是由散射系数经验公式直接得到,而是考虑了激光在生物组织中高度前向散射的特点,根据散射角和纵向深度的几何关系推导出来的。该模型还结合了扩散近似中的有效衰减系数作为轴向指数衰减因子。计算结果显示该模型提供了更加合理的光通量密度分布预测,得到的光分布接近蒙特卡罗模拟,而且能更加方便地应用到光传输相关的数值模拟中。

A modified light diffusion solution model was proposed from a heuristic version of beam spreading（BS） model and diffusion approximation（DA） theory. This new geometry deduction（GD） model adopted beam spreading idea, but the beam spreading did not get directly from scattering coefficient experience formula. And it considered the highly forward scattering characteristic of laser in bio - tissue, deducted from the geometry relation of scattering angle and axial depth. GD model combined the effective attenuation coefficient as axial exponential attenuation factor. Computation results showed GD model provided more reasonable predictions of light fluence rate distribution than BS and DA model, and the light distributions were similar to Monte Carlo（MC） simulation but more convenient when used in numerical simulation of light distribution related applications.