Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA.
Department of Laser Medicine, Chinese PLA General Hospital, Beijing, China.
Photochem Photobiol. 2017 Jul;93(4):1115-1122. doi: 10.1111/php.12719. Epub 2017 Feb 22.
This preclinical study examines light fluence, photodynamic therapy (PDT) dose and "apparent reacted singlet oxygen," [ O ] , to predict local control rate (LCR) for Photofrin-mediated PDT of radiation-induced fibrosarcoma (RIF) tumors. Mice bearing RIF tumors were treated with in-air fluences (50-250 J cm ) and in-air fluence rates (50-150 mW cm ) at Photofrin dosages of 5 and 15 mg kg and a drug-light interval of 24 h using a 630-nm, 1-cm-diameter collimated laser. A macroscopic model was used to calculate [ O ] and PDT dose based on in vivo explicit dosimetry of the drug concentration, light fluence and tissue optical properties. PDT dose and [ O ] were defined as a temporal integral of drug concentration and fluence rate, and singlet oxygen concentration consumed divided by the singlet oxygen lifetime, respectively. LCR was stratified for different dose metrics for 74 mice (66 + 8 control). Complete tumor control at 14 days was observed for [ O ] ≥ 1.1 mm or PDT dose ≥1200 μm J cm but cannot be predicted with fluence alone. LCR increases with increasing [ O ] and PDT dose but is not well correlated with fluence. Comparing dosimetric quantities, [ O ] outperformed both PDT dose and fluence in predicting tumor response and correlating with LCR.
本临床前研究检查了低光剂量、光动力疗法（PDT）剂量和“明显反应的单线态氧”[O]，以预测 Photofrin 介导的放射诱导纤维肉瘤（RIF）肿瘤 PDT 的局部控制率（LCR）。用空气内的光剂量（50-250 J cm）和空气内的光剂量率（50-150 mW cm），在 Photofrin 剂量为 5 和 15 mg kg 以及药物 - 光间隔为 24 h 的条件下，使用 630nm、1cm 直径的准直激光治疗携带 RIF 肿瘤的小鼠。使用宏观模型，根据药物浓度、光剂量和组织光学特性的体内显式剂量测定，计算[O]和 PDT 剂量。PDT 剂量和[O]分别定义为药物浓度和光剂量率的时间积分，以及消耗的单线态氧浓度除以单线态氧寿命的商。为 74 只小鼠（66+8 只对照）的不同剂量指标分层 LCR。观察到 14 天时[O]≥1.1mm 或 PDT 剂量≥1200μmJ cm 时完全肿瘤控制，但不能仅用光剂量来预测。LCR 随[O]和 PDT 剂量的增加而增加，但与光剂量相关性不强。比较剂量学参数，[O]在预测肿瘤反应和与 LCR 相关方面优于 PDT 剂量和光剂量。
