Mean dose rate in ultra-high dose rate electron irradiation is a significant predictor for O 2 consumption and H 2 O 2 yield

作者：Jacob P. Sunnerberg, Rongxiao Zhang, David J. Gladstone, Harold M. Swartz, Jiang Gui, Brian W. Pogue · 发表于：Physics in Medicine and Biology · 年份：2023 · DOI：10.1088/1361-6560/ace877 · 被引用次数：37 · 研究领域：Radiation Therapy and Dosimetry、Advanced Radiotherapy Techniques、Radiation Effects in Electronics

Abstract Objective . The objective of this study was to investigate the impact of mean and instantaneous dose rates on the production of reactive oxygen species (ROS) during ultra-high dose rate (UHDR) radiotherapy. The study aimed to determine whether either dose rate type plays a role in driving the FLASH effect, a phenomenon where UHDR radiotherapy reduces damage to normal tissues while maintaining tumor control. Approach . Assays of hydrogen peroxide (H 2 O 2 ) production and oxygen consumption (ΔpO 2 ) were conducted using UHDR electron irradiation. Aqueous solutions of 4% albumin were utilized as the experimental medium. The study compared the effects of varying mean dose rates and instantaneous dose rates on ROS yields. Instantaneous dose rate was varied by changing the source-to-surface distance (SSD), resulting in instantaneous dose rates ranging from 10 2 to 10 6 Gy s −1 . Mean dose rate was manipulated by altering the pulse frequency of the linear accelerator (linac) and by changing the SSD, ranging from 0.14 to 1500 Gy s −1 . Main results . The study found that both ΔH 2 O 2 and ΔpO 2 decreased as the mean dose rate increased. Multivariate analysis indicated that instantaneous dose rates also contributed to this effect. The variation in ΔpO 2 was dependent on the initial oxygen concentration in the solution. Based on the analysis of dose rate variation, the study estimated that 7.51 moles of H 2 O 2 were produced for every mole of O 2 consumed. Significance . The ...