Characterization of a shielded beam current transformer for ultra-high dose rate (FLASH) electron beam monitoring and dose reporting.

Medical physics Pub Date : 2025-06-05 DOI:10.1002/mp.17927
Thibault Bernelin, Bryan Muir, James Renaud, Karim Zerouali, Dominique Guillet, Louis Archambault, Arthur Lalonde
{"title":"Characterization of a shielded beam current transformer for ultra-high dose rate (FLASH) electron beam monitoring and dose reporting.","authors":"Thibault Bernelin, Bryan Muir, James Renaud, Karim Zerouali, Dominique Guillet, Louis Archambault, Arthur Lalonde","doi":"10.1002/mp.17927","DOIUrl":null,"url":null,"abstract":"<p><strong>Background: </strong>Real-time beam monitoring and accurate dose reporting is challenging in ultra-high dose rate (UHDR) electron beams. Although beam current transformers (BCTs) can effectively track parameters such as pulse width (PW) and repetition frequency for UHDR electron beams, recent work has highlighted their sensitivity to electric fields induced by transient charge buildup in irradiated media under UHDR conditions.</p><p><strong>Purpose: </strong>This study evaluates the performance of a novel electrostatically shielded BCT for real-time, high-accuracy dose monitoring in UHDR electron beams.</p><p><strong>Methods: </strong>Irradiations were conducted using the Mobetron linear accelerator configured for UHDR electron beams with energies of 6 and 9 MeV. A shielded BCT was implemented to monitor beam delivery, with dose calibration established using alanine dosimeters in solid water phantoms. Dose stability was assessed over short (7-day) and long (16-week) periods. The BCT's response to variations in PW, pulse number, and pulse repetition frequency was also evaluated to determine its robustness across beam configurations.</p><p><strong>Results: </strong>The BCT showed high reproducibility and accuracy, with standard deviations of the difference between BCT-predicted and alanine-measured doses within 0.21% over short-term measurements and 0.57% over long-term measurements, even when subject to large (10%) machine output adjustments. When varying beam parameters, the BCT maintained accurate dose prediction within 1.0% and 1.4% of alanine measurements for 6 and 9 MeV, respectively, with high linearity ( <math> <semantics> <mrow><msup><mi>R</mi> <mn>2</mn></msup> <mo>≥</mo></mrow> <annotation>${\\rm R}^2\\ge$</annotation></semantics> </math> 0.9997) across total doses.</p><p><strong>Conclusion: </strong>Shielded BCTs provide a stable and accurate solution for real-time dose monitoring in FLASH radiotherapy, demonstrating robustness against output fluctuations and beam parameter variations. While further calibration standardization is required, this study supports the feasibility of using shielded BCTs for reliable UHDR dose monitoring, facilitating safe and precise implementation of FLASH radiotherapy in preclinical and clinical settings.</p>","PeriodicalId":94136,"journal":{"name":"Medical physics","volume":" ","pages":""},"PeriodicalIF":0.0000,"publicationDate":"2025-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Medical physics","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1002/mp.17927","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 0

Abstract

Background: Real-time beam monitoring and accurate dose reporting is challenging in ultra-high dose rate (UHDR) electron beams. Although beam current transformers (BCTs) can effectively track parameters such as pulse width (PW) and repetition frequency for UHDR electron beams, recent work has highlighted their sensitivity to electric fields induced by transient charge buildup in irradiated media under UHDR conditions.

Purpose: This study evaluates the performance of a novel electrostatically shielded BCT for real-time, high-accuracy dose monitoring in UHDR electron beams.

Methods: Irradiations were conducted using the Mobetron linear accelerator configured for UHDR electron beams with energies of 6 and 9 MeV. A shielded BCT was implemented to monitor beam delivery, with dose calibration established using alanine dosimeters in solid water phantoms. Dose stability was assessed over short (7-day) and long (16-week) periods. The BCT's response to variations in PW, pulse number, and pulse repetition frequency was also evaluated to determine its robustness across beam configurations.

Results: The BCT showed high reproducibility and accuracy, with standard deviations of the difference between BCT-predicted and alanine-measured doses within 0.21% over short-term measurements and 0.57% over long-term measurements, even when subject to large (10%) machine output adjustments. When varying beam parameters, the BCT maintained accurate dose prediction within 1.0% and 1.4% of alanine measurements for 6 and 9 MeV, respectively, with high linearity ( R 2 ${\rm R}^2\ge$ 0.9997) across total doses.

Conclusion: Shielded BCTs provide a stable and accurate solution for real-time dose monitoring in FLASH radiotherapy, demonstrating robustness against output fluctuations and beam parameter variations. While further calibration standardization is required, this study supports the feasibility of using shielded BCTs for reliable UHDR dose monitoring, facilitating safe and precise implementation of FLASH radiotherapy in preclinical and clinical settings.

用于超高剂量率电子束监测和剂量报告的屏蔽束电流互感器的特性。
背景:超高剂量率(UHDR)电子束的实时监测和准确剂量报告具有挑战性。虽然束流互感器(bct)可以有效地跟踪UHDR电子束的脉冲宽度(PW)和重复频率等参数,但最近的研究强调了它们对UHDR条件下辐照介质中瞬态电荷积累引起的电场的敏感性。目的:本研究评估了一种新型静电屏蔽BCT在UHDR电子束中实时、高精度剂量监测的性能。方法:采用Mobetron直线加速器对能量为6 MeV和9 MeV的超高dr电子束进行辐照。采用屏蔽式BCT监测光束输送,并在固体水幻影中用丙氨酸剂量计建立剂量校准。在短(7天)和长(16周)期间评估剂量稳定性。还评估了BCT对PW、脉冲数和脉冲重复频率变化的响应,以确定其跨波束配置的鲁棒性。结果:BCT显示出很高的重现性和准确性,BCT预测的剂量与丙氨酸测量的剂量之间的差异的标准偏差在短期测量的0.21%和长期测量的0.57%以内,即使受到较大(10%)的机器输出调整。当改变光束参数时,BCT在6 MeV和9 MeV时分别在丙氨酸测量值的1.0%和1.4%范围内保持准确的剂量预测,并且在总剂量上具有高线性(r2≥${\rm R}^2\ge$ 0.9997)。结论:屏蔽bct为FLASH放疗的实时剂量监测提供了稳定、准确的解决方案,对输出波动和光束参数变化具有鲁棒性。虽然需要进一步的校准标准化,但本研究支持使用屏蔽bct进行可靠的UHDR剂量监测的可行性,有助于在临床前和临床环境中安全、精确地实施FLASH放疗。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
求助全文
约1分钟内获得全文 求助全文
来源期刊
自引率
0.00%
发文量
0
×
引用
GB/T 7714-2015
复制
MLA
复制
APA
复制
导出至
BibTeX EndNote RefMan NoteFirst NoteExpress
×
提示
您的信息不完整,为了账户安全,请先补充。
现在去补充
×
提示
您因"违规操作"
具体请查看互助需知
我知道了
×
提示
确定
请完成安全验证×
copy
已复制链接
快去分享给好友吧!
我知道了
右上角分享
点击右上角分享
0
联系我们:info@booksci.cn Book学术提供免费学术资源搜索服务,方便国内外学者检索中英文文献。致力于提供最便捷和优质的服务体验。 Copyright © 2023 布克学术 All rights reserved.
京ICP备2023020795号-1
ghs 京公网安备 11010802042870号
Book学术文献互助
Book学术文献互助群
群 号:604180095
Book学术官方微信