Significance: Raman spectroscopy (RS) applied to surgical guidance is attracting attention among scientists in biomedical optics. Offering a computational platform for studying depth-resolved RS and probing molecular specificity of different tissue layers is of crucial importance to increase the precision of these techniques and facilitate their clinical adoption. Aim: The aim of this work was to present a rigorous analysis of inelastic scattering depth sampling and elucidate the relationship between sensing depth of the Raman effect and optical properties of the tissue under interrogation. Approach: A new Monte Carlo (MC) package was developed to simulate absorption, fluorescence, elastic, and inelastic scattering of light in tissue. The validity of the MC algorithm was demonstrated by comparison with experimental Raman spectra in phantoms of known optical properties using nylon and polydimethylsiloxane as Raman-active compounds. A series of MC simulations were performed to study the effects of optical properties on Raman sensing depth for an imaging geometry consistent with single-point detection using a handheld fiber optics probe system. Results: The MC code was used to estimate the Raman sensing depth of a handheld fiber optics system. For absorption and reduced scattering coefficients of 0.001 and 1 mm − 1, the sensing depth varied from 105 to 225 μm for a range of Raman probabilities from 10 − 6 to 10 − 3. Further, for a realistic Raman probability of 10 − 6, the sensing depth ranged between 10 and 600 μm for the range of absorption coefficients 0.001 to 1.4 mm − 1 and reduced scattering coefficients of 0.5 to 30 mm − 1. Conclusions: A spectroscopic MC light transport simulation platform was developed and validated against experimental measurements in tissue phantoms and used to predict depth sensing in tissue. It is hoped that the current package and reported results provide the research community with an effective simulating tool to improve the development of clinical applications of RS.

中文翻译：

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生物组织中光谱蒙特卡罗光传输模拟技术和拉曼散射深度传感分析的实验验证

意义：应用于手术引导的拉曼光谱（RS）正引起生物医学光学科学家的关注。提供用于研究深度分辨 RS 和探测不同组织层的分子特异性的计算平台对于提高这些技术的精度并促进其临床采用至关重要。目的：这项工作的目的是对非弹性散射深度采样进行严格的分析，并阐明拉曼效应的传感深度与受审组织的光学特性之间的关系。方法：开发了一种新的 Monte Carlo (MC) 包来模拟光在组织中的吸收、荧光、弹性和非弹性散射。MC 算法的有效性通过与使用尼龙和聚二甲基硅氧烷作为拉曼活性化合物的已知光学特性的体模中的实验拉曼光谱进行比较来证明。进行了一系列 MC 模拟，以研究光学特性对拉曼传感深度的影响，以获得与使用手持光纤探头系统进行单点检测一致的成像几何。结果： MC 代码用于估计手持光纤系统的拉曼传感深度。对于 0.001 和 1 mm - 1 的吸收和减少散射系数，对于 10 - 6 到 10 - 3 的拉曼概率范围，传感深度从 105 到 225 μm 不等。此外，对于 10 - 6 的实际拉曼概率，对于 0.001 到 1 的吸收系数范围，传感深度范围在 10 到 600 μm 之间。4 mm - 1 和减少的散射系数为 0.5 到 30 mm - 1。 结论：开发了光谱 MC 光传输模拟平台，并针对组织体模中的实验测量进行了验证，并用于预测组织中的深度感应。希望当前的包和报告的结果为研究界提供有效的模拟工具，以改善 RS 临床应用的发展。