聚焦光束在生物组织中传输的数值模拟  

Numerical simulation of focused optical beam in tissue samples

作　　者：林林[1] 张梅[2] 张怀岺[1] 

机构地区：[1]广东医学院生物医学工程教研室,广东东莞523808 [2]东莞理工学院电子工程系,广东东莞523808

出　　处：《中国医学影像技术》2010年第12期2375-2378,共4页Chinese Journal of Medical Imaging Technology

基　　金：东莞市科技计划项目(200910815252);湛江市科技计划项目(2008C10017)

摘　　要：目的模拟光子在生物组织类物质中的传输过程,分析漫反射光能分布和组织内部目标区域内光能分布特性。方法采用蒙特卡洛数值模拟方法,在生物组织内设定目标区域,将光子分为一类和二类光子进行研究。模拟高斯聚焦光束入射并记录目标区域的光能密度分布以及漫反射光子的能量状态和平均散射次数。结果在目标区域,被散射的一类光子数目随聚焦深度的增加衰减迅速。目标区域外被散射的二类光子的能量分布和平均散射次数基本恒定,与聚焦位置无关。在组织内部聚焦位置的能量密度分布与束腰半径和聚焦深度相关。结论在散射作用下,一类光子和二类光子随聚焦深度具有不同的衰减特性。聚焦于目标区域的光能密度分布存在扩散现象,高斯光束的束腰越小的光束产生的扩散现象越严重,透射深度越浅。数值计算结果可为生物医学光学成像和光动力医疗研究提供参考。Objective To simulate photons transport in tissue samples and analyze the distribution of backscattered optical energy on the surface and inside the tissue samples,a statistical method was set up based on optical properties of samples. Methods Monte Carlo method was introduced to numerical simulation. The photons were classified as class Ⅰ and class Ⅱ,and the average scattering events and energy status of photons were recorded. Results The number of class Ⅰ photons decreased rapidly with the depth of target area. The number and distribution of classⅡ photons were independent of probing depth. In target area,optical intensity was determined by the waist of Gassian optical beam and the depth of focus area. Conlusion As results of scattering,class Ⅰ and class Ⅱ photons have different relationship with probing depth. Optical intensity dispersed in the target area and the smaller waist of focus beam penetrates shallower into tissue samples. The results are important to biological imaging and photodynamic therapy.

关 键 词：蒙特卡洛方法 束腰半径 光学成像 漫反射 

分 类 号：R817.51[医药卫生—影像医学与核医学]