皮肤三层模型的Monte Carlo法模拟激光多普勒血流测量

Three-layered model Monte Carlo simulation of skin for laser Doppler blood flow measurement

本文提出了用Monte Carlo法模拟光子流在表皮、真皮及皮下组织中的传播。经过对模拟结果的分析,提出通过改变环状探测器与入射光束的距离来探测不同深度血流层的血流速度;发现频谱的指数下降规律;指出在血球浓度较小时,平均频移反映红血球的平均速率,在浓度较高时反映红血球的均方根速率;本文还给出了不同血球浓度下光子的穿透深度。

A three-layered model of Monte Carlo simulation for photon flux in skin was presented. From the results of simulation we know that by varying the distance between the inner edge of the ring detector and the beam, we can measured the blood flow at different depths. The dependence of detected photon number on the frequency shift showed an exponetial decrease. By varying the blood volume fraction (Vb) , we investigated the effect of multiple scattering on the total frequency shift and the mean frequency shift. When Vb<C 0. 01, the mean frequency shift was a constant and it reflected the mean velocity of red blood cells, while Vb>0. 01, it reflected the root-mean-square velocity.