University of Pennsylvania, Department of Radiation Oncology, Philadelphia, Pennsylvania, United States.
University of Pennsylvania, Department of Bioengineering, Philadelphia, Pennsylvania, United States.
J Biomed Opt. 2024 Jan;29(1):018001. doi: 10.1117/1.JBO.29.1.018001. Epub 2024 Jan 13.
Photodynamic therapy (PDT) is an established cancer treatment utilizing light-activated photosensitizers (PS). Effective treatment hinges on the PDT dose-dependent on PS concentration and light fluence-delivered over time. We introduce an innovative eight-channel PDT dose dosimetry system capable of concurrently measuring light fluence and PS concentration during treatment.
We aim to develop and evaluate an eight-channel PDT dose dosimetry system for simultaneous measurement of light fluence and PS concentration. By addressing uncertainties due to tissue variations, the system enhances accurate PDT dosimetry for improved treatment outcomes.
The study positions eight isotropic detectors strategically within the pleural cavity before PDT. These detectors are linked to bifurcated fibers, distributing signals to both a photodiode and a spectrometer. Calibration techniques are applied to counter tissue-related variations and improve measurement accuracy. The fluorescence signal is normalized using the measured light fluence, compensating for variations in tissue properties. Measurements were taken in 78 sites in the pleural cavities of 20 patients.
Observations reveal minimal Photofrin concentration variation during PDT at each site, juxtaposed with significant intra- and inter-patient heterogeneities. Across 78 treated sites in 20 patients, the average Photofrin concentration for all 78 sites is , with a median concentration of . The average PDT dose for all 78 sites is , with a median dose of . A significant variation in PDT doses is observed, with a maximum difference of 3.1 times among all sites within one patient and a maximum difference of 9.8 times across all patients.
The introduced eight-channel PDT dose dosimetry system serves as a valuable real-time monitoring tool for light fluence and PS concentration during PDT. Its ability to mitigate uncertainties arising from tissue properties enhances dosimetry accuracy, thus optimizing treatment outcomes and bolstering the effectiveness of PDT in cancer therapy.
光动力疗法（PDT）是一种利用光激活光敏剂（PS）的成熟癌症治疗方法。有效的治疗取决于 PDT 剂量，这取决于 PS 浓度和随时间传递的光通量。我们引入了一种创新的八通道 PDT 剂量剂量测定系统，能够在治疗过程中同时测量光通量和 PS 浓度。
我们旨在开发和评估一种用于同时测量光通量和 PS 浓度的八通道 PDT 剂量剂量测定系统。通过解决由于组织变化引起的不确定性，该系统提高了 PDT 剂量的准确性，从而改善了治疗效果。
在 PDT 之前，研究将八个各向同性探测器战略性地定位在胸膜腔内。这些探测器与分叉光纤相连，将信号分配到光电二极管和分光光度计。应用校准技术来抵消与组织相关的变化并提高测量精度。通过测量的光通量对荧光信号进行归一化，补偿组织特性的变化。在 20 名患者的胸膜腔的 78 个部位进行了测量。
观察结果表明，在每个部位的 PDT 过程中，最小光动力疗法的 Photofrin 浓度变化，而患者内部和患者之间存在显著的异质性。在 20 名患者的 78 个治疗部位中，所有 78 个部位的 Photofrin 平均浓度为 ，中位数浓度为 。所有 78 个部位的平均 PDT 剂量为 ，中位数剂量为 。在一个患者的所有部位中观察到 PDT 剂量存在显著差异，最大差异为 3.1 倍，在所有患者中最大差异为 9.8 倍。
引入的八通道 PDT 剂量剂量测定系统是一种用于在 PDT 过程中实时监测光通量和 PS 浓度的有价值的工具。它能够减轻由于组织特性引起的不确定性，从而提高剂量测定的准确性，从而优化治疗效果并增强 PDT 在癌症治疗中的有效性。
