Reactive oxygen species explicit dosimetry for Photofrin-mediated pleural photodynamic therapy

Abstract

Reactive oxygen species explicit dosimetry (ROSED) has been recently developed and demonstrated to be able to better correlate with treatment outcome in both preclinical type I and type II PDT. ROSED involves direct measurements of in-vivo light fluence (rate), invivo photosensitizer concentration and tissue oxygenation to calculate for reacted ROS concentration ([ROS]rx) generated by PDT processes. In this study, we demonstrated ROSED in an ongoing Phase II clinical trial of Photofrin-mediated PDT for pleural mesothelioma [1]. We measured light fluence rate and PS concentration using isotropic detectors and tissue blood flow using DCS contact probes that are sutured on the pleural cavity wall. 7 patients were measured during the period of 2016-2018, which includes 2 patients with one DCS measurement location and 5 patients with two DCS measurements on different locations on the pleural cavity wall. Different dose metrics, including light fluence, PDT dose and [ROS]rx calculated based on light fluence, photosensitizer concentration, and blood flow were compared.