Palmiero Allison, Liu Kevin, Colnot Julie, Chopra Nitish, Neill Denae, Connell Luke, Velasquez Brett, Koong Albert C, Lin Steven H, Balter Peter, Tailor Ramesh, Robert Charlotte, Germond Jean-François, Gonçalves Jorge Patrik, Geyer Reiner, Beddar Sam, Moeckli Raphael, Schüler Emil
Department of Radiation Oncology, James Cancer Hospital and Solove Research Institute, The Ohio State University, Columbus, Ohio, USA.
Division of Radiation Oncology, Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA.
Med Phys. 2025 Feb;52(2):1207-1223. doi: 10.1002/mp.17483. Epub 2024 Oct 27.
FLASH or ultra-high dose rate (UHDR) radiation therapy (RT) has gained attention in recent years for its ability to spare normal tissues relative to conventional dose rate (CDR) RT in various preclinical trials. However, clinical implementation of this promising treatment option has been limited because of the lack of availability of accelerators capable of delivering UHDR RT. Commercial options are finally reaching the market that produce electron beams with average dose rates of up to 1000 Gy/s. We established a framework for the acceptance, commissioning, and periodic quality assurance (QA) of electron FLASH units and present an example of commissioning.
A protocol for acceptance, commissioning, and QA of UHDR linear accelerators was established by combining and adapting standards and professional recommendations for standard linear accelerators based on the experience with UHDR at four clinical centers that use different UHDR devices. Non-standard dosimetric beam parameters considered included pulse width, pulse repetition frequency, dose per pulse, and instantaneous dose rate, together with recommendations on how to acquire these measurements.
The 6- and 9-MeV beams of an UHDR electron device were commissioned by using this developed protocol. Measurements were acquired with a combination of ion chambers, beam current transformers (BCTs), and dose-rate-independent passive dosimeters. The unit was calibrated according to the concept of redundant dosimetry using a reference setup.
This study provides detailed recommendations for the acceptance testing, commissioning, and routine QA of low-energy electron UHDR linear accelerators. The proposed framework is not limited to any specific unit, making it applicable to all existing eFLASH units in the market. Through practical insights and theoretical discourse, this document establishes a benchmark for the commissioning of UHDR devices for clinical use.
近年来，FLASH或超高剂量率（UHDR）放射治疗（RT）因其在各种临床前试验中相对于传统剂量率（CDR）RT能更好地保护正常组织的能力而受到关注。然而，由于缺乏能够提供UHDR RT的加速器，这种有前景的治疗选择在临床中的应用一直有限。商业上的选择终于进入市场，这些设备能产生平均剂量率高达1000 Gy/s的电子束。我们建立了一个电子FLASH装置验收、调试和定期质量保证（QA）的框架，并给出了一个调试示例。
结合并调整基于四个使用不同UHDR设备的临床中心的UHDR经验对标准直线加速器的标准和专业建议，建立了UHDR直线加速器验收、调试和QA的方案。考虑的非标准剂量学束参数包括脉冲宽度、脉冲重复频率、每脉冲剂量和瞬时剂量率，以及关于如何获取这些测量值的建议。
使用这个制定的方案对一台UHDR电子设备的6 MeV和9 MeV束进行了调试。使用电离室、束流变压器（BCT）和与剂量率无关的无源剂量计组合进行测量。根据冗余剂量学的概念，使用参考装置对该装置进行校准。
本研究为低能电子UHDR直线加速器的验收测试、调试和常规QA提供了详细建议。所提出的框架不限于任何特定装置，使其适用于市场上所有现有的eFLASH装置。通过实际见解和理论论述，本文为临床使用的UHDR装置调试建立了一个基准。
