生物医学光子学3-1

Chapter3ModelingLightPropagationinBiologicalTissue主要光传输模型的层次关系图第一节第三节第四节第五节第二节第二章Chapter3ModelingLightPropagationinBiologicalTissue3.1Monte-CarloSimulation3.2RadiativeTransferEquation3.3DiffsuionApproximation3.4Kubaka-MunkTheory3.5Adding-DoublingMethod最主要的两种：模拟MC法(AnalogueMonte-Carlo，AMC)方差减小MC法(VariancereductionMonte-Carlo，VRMC)§3.1Monte-Carlosimulationabsorptionemissionreflection§3.1Monte-CarlosimulationLightincidentMainsteps：PhotonInitializationPropagationDistanceMovingaphotonInternalreflectionAbsorptionorscatteringDirectionafterscatteringNewcoordinateafterscatteringPhotonterminationDetectiondetector§3.1Monte-Carlosimulation§3.1Monte-CarlosimulationMainsteps：PhotonInitializationPropagationDistanceMovingaphotonInternalreflectionAbsorptionorscatteringDirectionafterscatteringNewcoordinateafterscatteringPhotonterminationDetection§3.1Monte-CarlosimulationMainsteps：PhotonInitializationPropagationDistanceMovingaphotonInternalreflectionAbsorptionorscatteringDirectionafterscatteringNewcoordinateafterscatteringPhotonterminationDetection随机抽样原理图Principleofrandomlysampling§3.1Monte-CarlosimulationTissue§3.1Monte-Carlosimulation步骤：•光子初始化（PhotonInitialization）•决定传播距离（PropagationDistance）•移动光子（Movingaphoton）•内部反射（Internalreflection）?•吸收？散射？散射后方向？•散射后的新坐标？•消失（Photontermination）？•检测。§3.1Monte-Carlosimulation散射后的方向？折射§3.1Monte-Carlosimulation步骤：•光子初始化（PhotonInitialization）•决定传播距离（PropagationDistance）•移动光子（Movingaphoton）•内部反射（Internalreflection）?•吸收？散射？散射后方向？•散射后的新坐标？•消失（Photontermination）？•检测。§3.1Monte-Carlosimulation光子随机行走坐标系CoordinatesystemofrandomwalkingforphotonOYX’’Z’Y’新位置？§3.1Monte-Carlosimulation移动光子吸收？YesNoYesYesNoNoYes开始光子初始化光子在媒质中？行进步长随机产生内反射？更新所求统计量按散射角分布随机改变行进方向最一个光子？结束No§3.1Monte-CarlosimulationMonteCarlo模拟应用举例0.00.51.01.52.02.50.00.51.01.52.02.5r(mm)0.65mmEpidermis0.3mmDermis1.2mmSubcutaneous3.0mmBananashapepropagationpathofCWlightreflectedfromskin§3.1Monte-Carlosimulation(a)半无限组织模型的时间分辨MonteCarlo模拟。(b)三条曲线分别对应在源与探测器距离(c)归一化的光子强度与时间关系曲线，随着SDS增大，曲线逐渐展宽，光子平均飞行时间增大。§3.1Monte-CarlosimulationyxzMC中的光子行进方向表示复习§3.1Monte-CarlosimulationEndof3.1