Department of Radiation Oncology, Arthur G. James Cancer Hospital, Columbus, OH, USA.
Department of Radiation Oncology, University of Oklahoma Health Sciences Center and Stephenson Cancer Center, Oklahoma City, OK, USA.
Med Dosim. 2022;47(3):273-279. doi: 10.1016/j.meddos.2022.04.006. Epub 2022 May 26.
The aim of our study is to document our cases of choroidal melanoma treated with low dose rate (LDR) brachytherapy and to correlate the dosimetry and radiobiology with clinical effects and oncologic outcomes. Data from 157 patients treated from 2014 to 2018 with LDR brachytherapy were used for this investigation. Treatments used a collaborative ocular melanoma study eye plaque and Iodine-125 radioactive seeds. The seeds activities were chosen to deliver 85 Gy to the tumor apex or to a prescription point (if the apex < 5 mm). The plaque sizes used were 10, 12, 14, 16, 18, 20, and 22 mm including notched or deep notched. The plaques were modeled in Varian BrachyVision version 11.6 (Varian Medical Systems) with seed coordinates from the AAPM Task Group 129. The Task Group 43 from AAPM was used for brachytherapy dose planning. Dose data were extracted for the apex, prescription point, sclera, retina opposite to the implant, lens, macula, and optic disc. The radiobiological dosimetry were calculated using appropriate α/β ratios found in the literature and then correlated to clinical side effects. Average biologically effective dose for associated organs at risk were calculated in cases where toxicity occurred. These included: radiation cataract (70.66 Gy), disc atrophy (475.49 Gy), foveal atrophy (263.07 Gy), radiation papillopathy (373.45 Gy), radiation maculopathy (213.62 Gy), vitreous hemorrhage (1437.68 Gy), vascular occlusion (1080.93 Gy), nonproliferative retinopathy (1066.89 Gy), proliferative retinopathy (1590.71 Gy), exudative retinal detachment (1364.32 Gy), and rhegmatogenous retinal detachment (2265.54 Gy). Average biologically effective dose was higher in patients who developed radiation induced long term side effects than in the whole patient population except for radiation maculopathy. In spite of the small patient population and short-term follow-up, it is of interest to correlate the radiation induced effects and create a guideline for the improvement of the treatment of patients treated with LDR brachytherapy.
我们的研究目的是记录接受低剂量率（LDR）近距离放射治疗的脉络膜黑色素瘤病例，并将剂量学和放射生物学与临床效果和肿瘤学结果相关联。这项研究使用了 2014 年至 2018 年间接受 LDR 近距离放射治疗的 157 名患者的数据。治疗采用了协作性眼部黑色素瘤研究眼斑和碘 125 放射性种子。种子的活性被选择为将 85Gy 输送到肿瘤顶点或处方点（如果顶点<5mm）。使用的斑块大小为 10、12、14、16、18、20 和 22mm，包括带槽或深槽。斑块在 Varian BrachyVision 版本 11.6（Varian Medical Systems）中建模，种子坐标来自 AAPM Task Group 129。AAPM 的 Task Group 43 用于近距离放射治疗剂量规划。从 AAPM Task Group 129 提取了顶点、处方点、巩膜、与植入物相对的视网膜、晶状体、黄斑和视盘的剂量数据。使用文献中发现的适当的α/β比值计算放射生物学剂量，并将其与临床副作用相关联。在发生毒性的情况下，计算了相关危险器官的平均生物有效剂量。这些包括：放射性白内障（70.66Gy）、盘萎缩（475.49Gy）、黄斑萎缩（263.07Gy）、视乳头放射性病变（373.45Gy）、黄斑放射性病变（213.62Gy）、玻璃体积血（1437.68Gy）、血管闭塞（1080.93Gy）、非增殖性视网膜病变（1066.89Gy）、增殖性视网膜病变（1590.71Gy）、渗出性视网膜脱离（1364.32Gy）和孔源性视网膜脱离（2265.54Gy）。与整个患者群体相比，患有放射诱导长期副作用的患者的平均生物有效剂量更高，除了黄斑放射性病变。尽管患者人群较小，随访时间短，但关联放射诱导作用并为改善接受 LDR 近距离放射治疗的患者的治疗制定指南是很有意义的。
