Effect of dose rate on antitumor activity in hypoxic cells by using flattening filter free beams

Q4 Health Professions
T. Hara, M. Tominaga, K. Yajyu, Risa Kouzaki, A. Hanyu, H. Yamada, M. Sasaki, S. Azane, Y. Uto
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引用次数: 3

Abstract

Background: Recently, the Fla ening Filter Free (FFF) beams, which allow a dose rate increase of up to four mes compared to the normal dose rate, have been incorporated into radia on therapy machines. The aim of this study is to evaluate an tumor ac vity in hypoxic cells irradiated with different dose rates using FFF beams and to iden fy the casual mechanism for cellular damage during irradia on. Materials and Methods: EMT6 cells were treated with 95% N2 and 5% CO2 to maintain a hypoxic condi on. Three dose rates, namely, 6.27 Gy/min, 12.00 Gy/ min, and 18.82 Gy/min, were used to deliver the prescribed dose of 2 to 4 Gy using the TrueBeam linear accelerator. The number of colonies was counted to evaluate the cell surviving frac on. To inves gate the mode of ac on, addi onal experiments to detect reac ve oxygen species (ROS) by aminophenyl fluorescein (APF) assay, and DNA double-strand breaks (DSBs) by γH2AX assay were performed. Results: Irradia on of hypoxic cells using FFF beams increases an tumor ac vity as a func on of dose rate. The fluorescence of the APF assay was significantly increased when high dose rates were used. In addi on, results from our γH2AX assays show that the number of DNA DSBs increased as a func on of dose rate, in hypoxic cells. Conclusion: We demonstrate that there is a significant dose rate-dependent difference in an tumor ac vity in hypoxic cells, when FFF
剂量率对扁平无滤束照射缺氧细胞抗肿瘤活性的影响
背景:最近,与正常剂量率相比,允许剂量率增加高达4微米的无滤光剂(FFF)光束已被纳入治疗机的辐射中。本研究的目的是评估在不同剂量率的FFF光束照射下缺氧细胞的肿瘤活性,并确定照射期间细胞损伤的偶然机制。材料与方法:用95% N2和5% CO2处理EMT6细胞,维持低氧状态。使用TrueBeam直线加速器,分别使用6.27 Gy/min、12.00 Gy/min和18.82 Gy/min三种剂量率给药2 ~ 4gy。计数菌落数,评估细胞存活情况。为了探究acon的模式,我们还进行了氨基苯基荧光素(APF)法检测活性氧(ROS)和γ - h2ax法检测DNA双链断裂(DSBs)的实验。结果:FFF束辐照缺氧细胞可使肿瘤活性随剂量率的增加而增加。当使用高剂量率时,APF检测的荧光显著增加。此外,我们的γ - h2ax测定结果显示,在缺氧细胞中,DNA dsb的数量随剂量率的增加而增加。结论:我们证明缺氧细胞的肿瘤活性存在显著的剂量率依赖性差异,当FFF
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来源期刊
Iranian Journal of Radiation Research
Iranian Journal of Radiation Research RADIOLOGY, NUCLEAR MEDICINE & MEDICAL IMAGING-
CiteScore
0.67
自引率
0.00%
发文量
0
审稿时长
>12 weeks
期刊介绍: Iranian Journal of Radiation Research (IJRR) publishes original scientific research and clinical investigations related to radiation oncology, radiation biology, and Medical and health physics. The clinical studies submitted for publication include experimental studies of combined modality treatment, especially chemoradiotherapy approaches, and relevant innovations in hyperthermia, brachytherapy, high LET irradiation, nuclear medicine, dosimetry, tumor imaging, radiation treatment planning, radiosensitizers, and radioprotectors. All manuscripts must pass stringent peer-review and only papers that are rated of high scientific quality are accepted.
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