University of Rochester, Department of Physics and Astronomy, Rochester, New York, United States.
University of Rochester Medical Center, Department of Imaging Sciences, Rochester, New York, United States.
J Biomed Opt. 2024 Feb;29(2):027002. doi: 10.1117/1.JBO.29.2.027002. Epub 2024 Feb 27.
Efficacious photodynamic therapy (PDT) of abscess cavities requires personalized treatment planning. This relies on knowledge of abscess wall optical properties, which we report for the first time in human subjects.
The objective was to extract optical properties and photosensitizer concentration from spatially resolved diffuse reflectance measurements of abscess cavities prior to methylene blue (MB) PDT, as part of a phase 1 clinical trial.
Diffuse reflectance spectra were collected at the abscess wall of 13 human subjects using a custom fiber-optic probe and optical spectroscopy system, before and after MB administration. A Monte Carlo lookup table was used to extract optical properties.
Pre-MB abscess wall absorption coefficients at 665 nm were (0.03 to ) and (0.08 to ) post-MB. Reduced scattering coefficients at 665 nm were (4.8 to ) and (1.6 to ) for pre-MB and post-MB, respectively. Oxygen saturations were found to be (5.6% to 100%) pre-MB and (0.0001% to 76.4%) post-MB. Determined MB concentrations were (0 to ).
We observed substantial inter-subject variation in both native wall optical properties and MB uptake. This underscores the importance of making these measurements for patient-specific treatment planning.
有效的光动力疗法（PDT）需要对脓肿腔进行个性化治疗规划。这依赖于对脓肿壁光学特性的了解，我们首次在人体受试者中报告了这些特性。
本研究旨在从亚甲蓝（MB）PDT 之前脓肿腔的空间分辨漫反射测量中提取光学特性和光敏剂浓度，这是一项 1 期临床试验的一部分。
使用定制的光纤探头和光谱光学系统，在 MB 给药前后，从 13 名人类受试者的脓肿壁收集漫反射光谱。使用蒙特卡罗查找表提取光学特性。
MB 给药前，脓肿壁在 665nm 处的吸收系数为 （0.03 至 ）和 （0.08 至 ），MB 给药后，吸收系数为 （0.03 至 ）和 （0.08 至 ）。665nm 处的散射系数分别为 （4.8 至 ）和 （1.6 至 ），MB 给药前和 MB 给药后。MB 给药前，氧饱和度为 （5.6%至 100%），MB 给药后，氧饱和度为 （0.0001%至 76.4%）。确定的 MB 浓度为 （0 至 ）。
我们观察到天然壁光学特性和 MB 摄取在个体间存在很大的差异。这突显出为患者特定的治疗计划进行这些测量的重要性。
