中文摘要：

光在组织体中的传输过程是扩散光的随机吸收和散射的过程,采用辐射传输方程来表示,由于方程比较复杂,无法直接得到解析解,传统方法是通过蒙特卡罗（Monte Carlo）仿真模拟。通过对经典蒙特卡罗方法中的步长和权重的更改,完成对光子在组织体中传输过程的快速仿真。在相同的仿真条件下,同时对经典蒙特卡罗方法和改进的方法进行仿真实验,改进方法能够大幅度提高仿真速度;并对于含有异质子的组织体进行仿真,结果表明改进的方法不仅提高了速度,而且保证了实验结果的准确性。

英文摘要：

Light transmission in tissue is a random process of absorption and scattering of diffuse optical, and expressed by the radiative transfer equation. Because the equation is complex, it can＇ t get the analytic solution di- rectly, and the traditional method is the Monte Carlo simulation. A modified method is proposed in step and weight of traditional Monte Carlo simulation, which can complete the photons transmission process in tissue quickly. With the same simulation conditions, the experiment is simulated by the Monte Carlo method and improved method, and it shows the improved method can greatly improve the simulation speed. Then the simulation results with heteroge- neous medium show that the proposed method is effectiveness, Which can not only improve the speed, but also ensure the accuracy.