Commissioning of an ultra-high dose rate pulsed electron beam medical LINAC for FLASH RT preclinical animal experiments and future clinical human protocols
Commissioning of an ultra-high dose rate pulsed electron beam medical LINAC for FLASH RT preclinical animal experiments and future clinical human protocols
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DOI：
10.1002/mp.14885
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发表时间：
2021-05-14
期刊：
影响因子：
3.8
通讯作者：
Bailat, Claude
中科院分区：
文献类型：
--
作者：
Moeckli, Raphael;Jorge, Patrik Goncalves;Bailat, Claude
目的：介绍验收和调试情况，定义参考剂量，并为超高剂量率 (UHDR) 电子装置的质量评估 (QA) 程序准备参考数据，以验证其用于临床前动物 FLASH 放射治疗 (FLASH RT) 实验和 FLASH RT 临床人体方案。方法：使用常规 (CONV) 模式下的 9 MeV 电子束和在常规 (CONV) 模式下使用 6 和 9 MeV 的电子束对 Mobetron (R) 装置进行评估。 UHDR 模式（标称能量）。本次验收按照公司验收协议进行。调试包括确定设备的短期和长期稳定性、测量两个不同位置（每个脉冲方案有两种不同剂量）和不同准直器尺寸的百分比深度剂量曲线（PDD）和分布，以及评估改变脉冲宽度和脉冲重复频率时这些参数的可变性。使用冗余且经过验证的剂量测定策略、丙氨酸和放射变色膜以及用于某些测量的高级马库斯电离室进行测量。结果：验收测试均在公司验收协议的公差范围内。在所有情况下，脉冲宽度的线性度均在 1.5% 以内。在所有情况下，脉冲重复频率对输送剂量的影响均不超过 2%，但 90 Hz 除外，其中最大差异为 3.8%。参考剂量测定显示丙氨酸和胶片之间具有良好的一致性，变化为 2.2% 或更小。短期（或长期）稳定性低于 1.0%（或 1.8%），并且在 CONV 和 UHDR 模式下相同。在两个位置测量 PDD、分布图和参考剂量测定，提供两种特定剂量率（约 9 Gy/脉冲和 3 Gy/脉冲）的数据。在 90% 等剂量测试的两个位置上，最大光束尺寸分别为 4 和 6 厘米。 CONV 和 UHDR 模式在测试的光束特性方面没有差异。结论：该设备被委托用于 FLASH RT 临床前生物实验以及 FLASH RT 临床人体方案。 (C) 2021 年美国医学物理学家协会
Purpose: To present the acceptance and the commissioning, to define the reference dose, and to prepare the reference data for a quality assessment (QA) program of an ultra-high dose rate (UHDR) electron device in order to validate it for preclinical animal FLASH radiotherapy (FLASH RT) experiments and for FLASH RT clinical human protocols.Methods: The Mobetron (R) device was evaluated with electron beams of 9 MeV in conventional (CONV) mode and of 6 and 9 MeV in UHDR mode (nominal energy). The acceptance was performed according to the acceptance protocol of the company. The commissioning consisted of determining the short- and long-term stability of the device, the measurement of percent depth dose curves (PDDs) and profiles at two different positions (with two different dose per pulse regimen) and for different collimator sizes, and the evaluation of the variability of these parameters when changing the pulse width and pulse repetition frequency. Measurements were performed using a redundant and validated dosimetric strategy with alanine and radiochromic films, as well as Advanced Markus ionization chamber for some measurements.Results: The acceptance tests were all within the tolerances of the company's acceptance protocol. The linearity with pulse width was within 1.5% in all cases. The pulse repetition frequency did not affect the delivered dose more than 2% in all cases but 90 Hz, for which the larger difference was 3.8%. The reference dosimetry showed a good agreement within the alanine and films with variations of 2.2% or less. The short-term (resp. long-term) stability was less than 1.0% (resp. 1.8%) and was the same in both CONV and UHDR modes. PDDs, profiles, and reference dosimetry were measured at two positions, providing data for two specific dose rates (about 9 Gy/pulse and 3 Gy/pulse). Maximal beam size was 4 and 6 cm at 90% isodose in the two positions tested. There was no difference between CONV and UHDR mode in the beam characteristics tested.Conclusions: The device is commissioned for FLASH RT preclinical biological experiments as well as FLASH RT clinical human protocols. (C) 2021 American Association of Physicists in Medicine