Martelli F, Sassaroli A, Zaccanti G, Yamada Y
Mechanical Engineering Laboratory, Biomechanics Division, AIST, MITI, Tsukuba, Ibaraki, Japan.
Phys Med Biol. 1999 May;44(5):1257-75. doi: 10.1088/0031-9155/44/5/013.
By using the diffusion approximation of the radiative transfer equation and the partial-current boundary condition, an analytical expression for the angular dependence of the specific intensity emerging from a diffusive medium has been obtained. The analytical expression for the angular distribution has been validated by comparisons with the results of Monte Carlo simulations. By using the diffusion equation and the extrapolated boundary condition, an heuristic analytical expression for the diffuse time-resolved reflectance has also been obtained by assuming that the photon flux is simply proportional to the fluence rate. For the case of the semi-infinite medium, comparisons with Monte Carlo results are presented and time-resolved reflectance data are fitted with the simple fluence rate formula. The results obtained show that the simple expression correctly describes the time-resolved reflectance giving an error in the retrieved optical parameters smaller than that of other commonly used expressions.
通过使用辐射传输方程的扩散近似和部分电流边界条件，得到了从扩散介质中出射的比强度角分布的解析表达式。通过与蒙特卡罗模拟结果进行比较，验证了角分布的解析表达式。通过使用扩散方程和外推边界条件，通过假设光子通量与注量率简单成正比，还得到了漫反射时间分辨反射率的启发式解析表达式。对于半无限介质的情况，给出了与蒙特卡罗结果的比较，并将时间分辨反射率数据与简单的注量率公式进行了拟合。所得结果表明，该简单表达式正确地描述了时间分辨反射率，在反演光学参数时产生的误差小于其他常用表达式。
