First experience with third-party validations: A robust calibration and QA procedure for proton FLASH delivery

IF 2.2 4区医学 Q3 RADIOLOGY, NUCLEAR MEDICINE & MEDICAL IMAGING

Journal of Applied Clinical Medical Physics Pub Date : 2025-09-27 DOI:10.1002/acm2.70269

Chih-Chiang Chang, Balaji Selvaraj, Xingyi Zhao, Jacob Rembish, Paige A. Taylor, Alexander Bookbinder, Chingyun Cheng, J. Isabelle Choi, Charles B. Simone II, Haibo Lin, Minglei Kang

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引用次数: 0

Abstract

Background

Proton FLASH radiotherapy, delivering ultra-high dose rates, shows promise in reducing normal tissue toxicity while maintaining tumor control. However, accurate dosimetry and quality assurance (QA) for FLASH remain challenging due to the extreme dose rates involved. Developing reliable calibration and QA procedures is crucial for advancing FLASH towards clinical implementation.

Purpose

To present an effective routine calibration and QA procedure for proton FLASH delivery to ensure high-quality dosimetry performance for preclinical and clinical delivery.

Methods

A high temporospatial resolution strip ionization chamber array (SICA) detector was mounted to the treatment nozzle, which was calibrated using an Advanced Markus ion chamber (IC) under variable dose and ultra-high dose rates. The calibration curve was used to monitor the delivery in real-time. The maximum beam current was 215 nA at the isocenter at the highest energy of the cyclotron (250 MeV). Third-party IROC (Imaging and Radiation Oncology Core) thermoluminescent dosimeters (TLDs) were requested to verify the accuracy and effectiveness of the calibration and validation procedure. A transmission field with a field size of 3 × 3 cm² was designed to deliver 2000 cGy doses with a field-averaged dose rate varying from 36 to 76.5 Gy/s.

Results

The entire calibration process took less than 10 minutes as part of routine daily QA. The calibration curve between the SICA detector and IC demonstrated an R-value of almost 1.00. The SICA detector measured each delivery, providing critical data for FLASH analysis, including field size, dose, delivery time, and dose rate. Based on real-time dose and dose rate monitoring, the planned and delivered doses were within 1% accuracy according to third-party TLD measurements.

Conclusion

As demonstrated by IROC measurements, effective calibration and QA using a SICA detector for proton FLASH delivery can ensure high accuracy in real-time dose and dose rate monitoring, paving the way for future clinical applications.

Abstract Image

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首次第三方验证经验：质子FLASH交付的可靠校准和质量保证程序

质子FLASH放射治疗，提供超高剂量率，显示出在维持肿瘤控制的同时降低正常组织毒性的希望。然而，由于涉及的极端剂量率，对FLASH的准确剂量测定和质量保证（QA）仍然具有挑战性。制定可靠的校准和质量保证程序对于推进FLASH临床应用至关重要。目的介绍一种有效的质子FLASH给药的常规校准和质量保证程序，以确保临床前和临床给药的高质量剂量学性能。方法将高时空分辨率的条形电离室阵列（SICA）探测器安装在处理喷嘴上，采用先进的Markus离子室（IC）在变剂量和超高剂量率下对处理喷嘴进行校准。利用标定曲线实时监测产程。在回旋加速器最高能量（250 MeV）时，等中心处的最大束流为215 nA。要求第三方IROC（成像和放射肿瘤学核心）热释光剂量计（tld）验证校准和验证程序的准确性和有效性。设计了一个场尺寸为3 × 3 cm2的传输场，可输送2000 cGy剂量，场平均剂量率为36 ~ 76.5 Gy/s。结果整个校准过程不到10分钟，是日常QA的一部分。SICA探测器与IC之间的校准曲线显示r值接近1.00。SICA探测器测量每次给药，为FLASH分析提供关键数据，包括场大小、剂量、给药时间和剂量率。基于实时剂量和剂量率监测，根据第三方TLD测量，计划和交付剂量的准确度在1%以内。结论IROC测量结果表明，使用SICA探测器对质子FLASH输送进行有效的校准和质量保证可以确保实时剂量和剂量率监测的准确性，为未来的临床应用铺平了道路。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Journal of Applied Clinical Medical Physics 医学-核医学

CiteScore

3.60

自引率

19.00%

发文量

331

审稿时长

3 months

期刊介绍： Journal of Applied Clinical Medical Physics is an international Open Access publication dedicated to clinical medical physics. JACMP welcomes original contributions dealing with all aspects of medical physics from scientists working in the clinical medical physics around the world. JACMP accepts only online submission. JACMP will publish: -Original Contributions: Peer-reviewed, investigations that represent new and significant contributions to the field. Recommended word count: up to 7500. -Review Articles: Reviews of major areas or sub-areas in the field of clinical medical physics. These articles may be of any length and are peer reviewed. -Technical Notes: These should be no longer than 3000 words, including key references. -Letters to the Editor: Comments on papers published in JACMP or on any other matters of interest to clinical medical physics. These should not be more than 1250 (including the literature) and their publication is only based on the decision of the editor, who occasionally asks experts on the merit of the contents. -Book Reviews: The editorial office solicits Book Reviews. -Announcements of Forthcoming Meetings: The Editor may provide notice of forthcoming meetings, course offerings, and other events relevant to clinical medical physics. -Parallel Opposed Editorial: We welcome topics relevant to clinical practice and medical physics profession. The contents can be controversial debate or opposed aspects of an issue. One author argues for the position and the other against. Each side of the debate contains an opening statement up to 800 words, followed by a rebuttal up to 500 words. Readers interested in participating in this series should contact the moderator with a proposed title and a short description of the topic