Kozicki Marek, Jaszczak Malwina, Maras Piotr
Department of Mechanical Engineering, Informatics and Chemistry of Polymer Materials, Faculty of Materials Technologies and Textile Design, Lodz University of Technology, 90-543 Lodz, Poland.
Department of Radiotherapy Planning, Copernicus Hospital, 90-543 Lodz, Poland.
Materials (Basel). 2022 Mar 31;15(7):2550. doi: 10.3390/ma15072550.
This work presents the features of the PABIG 3D polymer gel dosimeter. It consists of two cross-linkers: poly(ethylene glycol) diacrylate (PEGDA), as one biacrylic component, and ,'-methylenebisacrylamide (MBA), which is another cross-linker often used in 3D dosimeters. Additionally, it contains oxygen scavenges of copper sulfate pentahydrate and ascorbic acid. All ingredients are embedded in a physical gel matrix of gelatine. Upon irradiation, the biacrylic cross-linking agents (PEGDA and MBA) undergo radical polymerisation and cross-linking, which is manifested by the appearance of the opacity of the intensity related to the absorbed dose. PABIG was irradiated with an oncological source of ionising radiation, and analysed by using a nuclear magnetic resonance (0.5 T). The following characteristics were obtained: (i) linear and dynamic dose-response of 0.5 to ~18 Gy and 40 Gy, respectively, (ii) dose sensitivity of 0.071 ± 0.001 Gy s, (iii) integral 3D dose distribution for at least 24 days after irradiation, (iv) adequate batch-to-batch reproducibility, (v) dose-response independent of irradiation with 6 MV photons, 15 MV photons, 6 MV photons FFF of 0.0168-0.1094 Gy/s dose rates, and (vi) soft tissue equivalence. The study showed that the features of PABIG confirm its suitability for use in 3D radiotherapy dosimetry.
这项工作展示了PABIG 3D聚合物凝胶剂量计的特性。它由两种交联剂组成：聚乙二醇二丙烯酸酯（PEGDA）作为一种双丙烯酸组分，以及N,N'-亚甲基双丙烯酰胺（MBA），后者是3D剂量计中常用的另一种交联剂。此外，它还含有五水硫酸铜和抗坏血酸作为氧清除剂。所有成分都嵌入在明胶的物理凝胶基质中。辐照后，双丙烯酸交联剂（PEGDA和MBA）发生自由基聚合和交联，这表现为与吸收剂量相关的强度不透明度的出现。用肿瘤电离辐射源对PABIG进行辐照，并使用核磁共振（0.5 T）进行分析。获得了以下特性：（i）分别在0.5至约18 Gy和40 Gy范围内的线性和动态剂量响应，（ii）剂量灵敏度为0.071±0.001 Gy/s，（iii）辐照后至少24天的积分3D剂量分布，（iv）足够的批次间重现性，（v）剂量响应与6 MV光子、15 MV光子、剂量率为0.0168 - 0.1094 Gy/s的6 MV光子FFF辐照无关，以及（vi）软组织等效性。该研究表明，PABIG的特性证实了其适用于3D放射治疗剂量测定。
