Fung K L Barry, Samim Masood, Gribble Adam, Barzda Virginijus, Vitkin I Alex
Division of Engineering Science, University of Toronto, Toronto, Ontario, Canada.
Division of Biophysics and Bioimaging, Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada.
J Biophotonics. 2018 Dec;11(12):e201800036. doi: 10.1002/jbio.201800036. Epub 2018 Jul 31.
Polarization-sensitive second harmonic generation (p-SHG) is a nonlinear optical microscopy technique that has shown great promise in biomedicine, such as in detecting changes in the collagen ultrastructure of the tumor microenvironment. However, the complex nature of light-tissue interactions and the heterogeneity of biological samples pose challenges in creating an analytical and experimental quantification platform for tissue characterization via p-SHG. We present a Monte Carlo (MC) p-SHG simulation model based on double Stokes-Mueller polarimetry for the investigation of nonlinear light-tissue interaction. The MC model predictions are compared with experimental measurements of second-order nonlinear susceptibility component ratio and degree of polarization (DOP) in rat-tail collagen. The observed trends in the behavior of these parameters as a function of tissue thickness, as well as the overall extent of agreement between MC and experimental results, are discussed. High sensitivities of the susceptibility ratio and DOP are observed for the varying tissue thickness on the incoming fundamental light propagation pathway.
偏振敏感二次谐波产生（p-SHG）是一种非线性光学显微镜技术，在生物医学领域已展现出巨大潜力，例如用于检测肿瘤微环境中胶原蛋白超微结构的变化。然而，光与组织相互作用的复杂性质以及生物样品的异质性，给通过p-SHG创建用于组织表征的分析和实验量化平台带来了挑战。我们提出了一种基于双斯托克斯 - 穆勒偏振测量法的蒙特卡罗（MC）p-SHG模拟模型，用于研究非线性光与组织的相互作用。将MC模型预测结果与大鼠尾部胶原蛋白中二阶非线性极化率分量比和偏振度（DOP）的实验测量结果进行了比较。讨论了这些参数随组织厚度变化的行为趋势，以及MC与实验结果之间的总体吻合程度。在入射基波光传播路径上，观察到极化率比和DOP对不同组织厚度具有高灵敏度。
