OCT系统中皮肤组织对光的漫反射和光能量吸收研究

Light Diffuse Reflection and Photon Energy Absorption of Skin in OCT System

针对光在高散射介质中的传播特性,研究了皮肤组织中径向漫反射强度R(r)和纵向能量吸收强度A(z).利用Matlab对高散射随机皮肤组织中光子的随机运行进行蒙特卡罗模拟计算,依次改变肌肉层参数,得到三类典型参数在不同取值时的R(r)与A(z).模拟结果表明,在其余参数不变,当吸收系数μα越大时,肌肉层中的能量衰减梯度越大,能量吸收强度的初值也越大,同时漫反射强度越小;当散射系数μs越大时,能量吸收强度的初值越大,衰减梯度也越大,漫反射强度的衰减梯度几乎相同;当各项异性因子g越大时,能量吸收强度的初值越小,即发生吸收的概率就越少,同时漫反射强度也越小;三类光学参数对R(r)影响程度相近并且较小,在半径为0.05cm范围内,漫反射强度均呈现出相类似的大梯度衰减.

According to the properties of light transmission in highly scattering medium,radial diffuse reflection intensity of R（r）and longitudinal energy absorption intensity of A（z）in the skin tissue are discussed.Stochastic motions of a bunch of photons in the highly scattering multi-layered skin were calculated and analyzed with Monte Carlo simulation based on the Matlab software.A series of R（r）and A（z）were obtained when the three typical kinds of parameters had different values by successively changing the parameters of the muscle layer.The calculation results show that,with the rest of the parameters unchanged the larger the absorption coefficientμsis,the greater the gradient of energy decay and the initial value of the A（z）in the muscle layer are and the smaller the R（r）is,with the scattering coefficientμsincreasing,the initial value of A（z）and the gradient of energy decay in the muscle layer become stronger,and gradients of R（r）with differentμsare almost the same.The greater the anisotropy factor g in the muscle layer is,the smaller the initial value of A（z）is,which means that the absorption of photons hardly happens,and the smaller R（r）is.The influences of the three types of optical parameters on R（r）are similar and weak,and every curve of R（r）presents similar and high gradient in the range with the radius being 0.05cm.