Yasui Keisuke, Hayashi Miuna, Otsuka Shiryu, Toshito Toshiyuki, Omachi Chihiro, Ichihara Masaya, Oshika Riki, Tominaga Yuki, Baba Hiromi, Shimizu Hidetoshi, Hayashi Naoki
Division of Medical Physics, School of Medical Sciences, Fujita Health University, Toyoake, Aichi, Japan.
Department of Radiology, Aichi Medical University Hospital, Nagakute, Aichi, Japan.
Med Phys. 2025 Jun;52(6):4996-5004. doi: 10.1002/mp.17790. Epub 2025 Mar 29.
Accurate dosimetry is important in radiotherapy, and all equipment used for radiotherapy shoud be audited by an independent external dose audit. Radiophotoluminescence glass dosimeter (RPLD) has excellent characteristics and is widely used for postal dose audit; however, postal dose audit for proton therapy using RPLD has not been established.
This study aims to develop a postal dose audit procedure for scanning proton beams using RPLD, estimate uncertainties, and conduct a multicenter pilot study to validate the methodology.
A postal toolkit was developed and a postal dose audit procedure for RPLD measurements of scanning proton beams was established in cooperation with several facilities that employ various accelerators, irradiation equipment, and treatment planning systems (TPS) for clinical use. Based on basic and previous studies, an uncertainty budget was developed for estimating relative uncertainty and pilot studies were conducted at each site. A method for postal dose audits was developed in a multicenter collaboration to develop an approach suitable for implementation across multiple facilities.
The relative response of 60 RPLDs for scanning proton beam examined in this study was 1.00 ± 1.28% mean ± standard deviation. The combined relative standard uncertainty of postal dosimetry for scanning proton beams using the RPLD was 2.97% (k = 1). Under the reference condition, the maximum differences between the ionization chamber measurement (IC) and TPS, RPLD and TPS, and RPLD and IC were 0.97, 1.88, and 2.12%, respectively. The maximum differences between the RPLD and ionization chamber for plateau measurements at 3 cm depth using single-energy and non-reference conditions were 11.31 and 4.02%, respectively.
We established a procedure for the postal dose audits of proton beams using RPLD and presented the results of a multicenter pilot study. By standardizing the reference conditions, the dosimetry uncertainty was estimated at 2.92%. The results demonstrated the feasibility of performing an independent third-party dose audit of scanning proton beams using RPLD, and for such postal dose audits for proton beams, the irradiation conditions should be standardized to reduce uncertainties. These results are expected to contribute to the development of proton beams.
精确的剂量测定在放射治疗中至关重要，所有用于放射治疗的设备都应由独立的外部剂量审核机构进行审核。放射性光致发光玻璃剂量计（RPLD）具有优异的特性，被广泛用于邮寄剂量审核；然而，使用RPLD进行质子治疗的邮寄剂量审核尚未确立。
本研究旨在开发一种使用RPLD对扫描质子束进行邮寄剂量审核的程序，估计不确定性，并开展一项多中心试点研究以验证该方法。
开发了一个邮寄工具包，并与多家临床使用各种加速器、照射设备和治疗计划系统（TPS）的机构合作，建立了一种使用RPLD测量扫描质子束的邮寄剂量审核程序。基于基础研究和先前的研究，制定了一个不确定性预算以估计相对不确定性，并在每个站点进行了试点研究。通过多中心合作开发了一种邮寄剂量审核方法，以制定一种适用于多个机构实施的方法。
本研究中检测的60个用于扫描质子束的RPLD的相对响应为平均值±标准差1.00±1.28%。使用RPLD进行扫描质子束邮寄剂量测定的组合相对标准不确定度为2.97%（k=1）。在参考条件下，电离室测量（IC）与TPS之间、RPLD与TPS之间以及RPLD与IC之间的最大差异分别为0.97%、1.88%和2.12%。在3cm深度使用单能和非参考条件进行坪区测量时，RPLD与电离室之间的最大差异分别为11.31%和4.02%。
我们建立了使用RPLD对质子束进行邮寄剂量审核的程序，并展示了多中心试点研究的结果。通过标准化参考条件，剂量测定不确定度估计为2.92%。结果证明了使用RPLD对扫描质子束进行独立第三方剂量审核的可行性，对于质子束的此类邮寄剂量审核，应标准化照射条件以降低不确定性。这些结果有望为质子束的发展做出贡献。
