中文摘要：

用蒙特卡罗方法模拟了准直激光束垂直入射于生物组织的过程,分析了光子在生物组织中的运动轨迹、光学参数对能量分布的影响、吸收能量密度和光能流率随组织厚度和半径的变化情况、组织表面径向和角向分辨的漫反射率的变化情况,并利用卷积模拟了高斯光束与平圆光束在生物组织中的传输。结果表明：准直光束入射组织时,能量主要集中在中央束轴附近;g因子增大,光子前向运动增强;吸收系数aμ增大,光子数的分布沿纵向和径向会同时减小;光能流率与吸收能量密度相比变化平滑;高斯光束的能量分布比平圆光束集中,变化迅速,中心位置处吸收能量密度大。

英文摘要：

A Monte Carlo method was used to study the light distribution in bio-tissues with a collimated light beam.The track of photons propagation,the energy intensity distribution with optical parameters,the absorption energy density and internal fluence with depths and radius,the change of radially and angularly resolved diffuse reflectances were analyzed.The propagation of the Gaussian beam and circularly flat beam in bio-tissues was simulated by using convolution.The results showed that when a collimated light beam propagated in the tissue,the energy was mainly concentrated in the vicinity of the central axis.The photons forward movement was enhanced when the g factor was increased.When the absorption coefficient became larger,the distribution of photons was reduced along the vertical and horizontal axis.The internal fluence changed more smoothly than the absorption energy density.The energy distribution of the Gaussian beam had a larger concentration than that of a circularly flat beam,changed more rapidly and had a larger energy absorption in the center.