Implementation of optically simulated luminescent dosimeter for quality control of gamma ray dose of an accelerator-based neutron source

IF 2 4区医学 Q3 RADIOLOGY, NUCLEAR MEDICINE & MEDICAL IMAGING

Journal of Applied Clinical Medical Physics Pub Date : 2024-08-27 DOI:10.1002/acm2.14493

Naonori Hu, Taiki Nakamura, Ryusuke Kataura, Keita Suga, Tetsuya Mukawa, Kazuhiko Akita, Akinori Sasaki, Mai Nojiri, Nishiki Matsubayashi, Takushi Takata, Hiroki Tanaka, Keiji Nihei, Koji Ono

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引用次数: 0

Abstract

Background

Neutron beams utilized for performing BNCT are composed of a mixture of neutrons and gamma rays. Although much of the dose delivered to the cancer cells comes from the high LET particles produced by the boron neutron capture reaction, the dose delivered to the healthy tissues from unwanted gamma rays cannot be ignored. With the increase in the number of accelerators for BNCT, a detector system that is capable of measuring gamma ray dose in a mixed neutron/gamma irradiation field is crucial. Currently, BeO TLDs encased in quartz glass are used to measure gamma ray dose in a BNCT irradiation field. However, this type of TLD is no longer commercially available. A replacement dosimetry system is required to perform the recommended ongoing quality assurance of gamma ray measurement for a clinical BNCT system.

Purpose

The purpose of this study is to evaluate the characteristics of a BeO OSLD detector system under a mixed neutron and gamma ray irradiation field and to assess the suitability of the system for routine quality assurance measurements of an accelerator-based BNCT facility.

Methods

The myOSLD system by RadPro International GmbH was evaluated using the accelerator-based neutron source designed for clinical BNCT (NeuCure BNCT system). The readout constancy, linearity, dose rate effect, and fading effect of the OSLD were evaluated. Free-in-air and water phantom measurements were performed and compared with the TLD results and Monte Carlo simulation results. The PHITS Monte Carlo code was used for this study.

Results

The readout constancy was found to be stable over a month-long period and similar to the TLD results. The OSLD readout signal was found to be linear, with a high coefficient of determination (R² ≥ 0.999) up to a proton charge of 3.6 C. There was no significant signal fading or dose rate dependency. The central axis depth dose and off-axis dose profile measurements agreed with both the TLD and Monte Carlo simulation results, within one standard deviation.

Conclusion

The myOSLD system was characterized using an accelerator system designed for clinical BNCT. The experimental measurements confirmed the OSLD achieved similar, if not superior to, the currently utilized dosimetry system for routine QA of an accelerator-based BNCT system. The OSLD system would be a suitable replacement for the current TLD system for performing routine QA of gamma ray dose measurement in a BNCT irradiation field.

Abstract Image

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采用光学模拟发光剂量计对加速器中子源的伽马射线剂量进行质量控制。

背景：用于进行 BNCT 的中子束是由中子和伽马射线混合组成的。虽然癌细胞受到的大部分剂量来自硼中子俘获反应产生的高 LET 粒子，但健康组织受到的不需要的伽马射线剂量也不容忽视。随着用于 BNCT 的加速器数量的增加，能够测量中子/伽马混合辐照场中伽马射线剂量的探测器系统变得至关重要。目前，BeO TLD 封装在石英玻璃中，用于测量 BNCT 辐照场中的伽马射线剂量。然而，这种类型的 TLD 已不再在市场上销售。目的：本研究的目的是评估 BeO OSLD 探测器系统在中子和伽马射线混合辐照场下的特性，并评估该系统是否适合用于基于加速器的 BNCT 设备的常规质量保证测量：方法：使用为临床 BNCT 设计的加速器中子源（NeuCure BNCT 系统）对 RadPro International GmbH 的 myOSLD 系统进行了评估。对 OSLD 的读出恒定性、线性度、剂量率效应和衰减效应进行了评估。对自由空气和水模型进行了测量，并与 TLD 结果和蒙特卡罗模拟结果进行了比较。本研究使用了 PHITS 蒙特卡罗代码：结果：在长达一个月的时间里，读出恒定性保持稳定，与 TLD 结果相似。OSLD 的读出信号是线性的，在质子电荷为 3.6 C 时具有较高的决定系数（R2 ≥ 0.999）。中心轴深度剂量和离轴剂量曲线测量结果与 TLD 和蒙特卡罗模拟结果一致，误差在一个标准偏差以内：使用为临床 BNCT 设计的加速器系统对 myOSLD 系统进行了鉴定。实验测量结果证实，在基于加速器的 BNCT 系统的常规质量保证方面，OSLD 与目前使用的剂量测定系统具有相似甚至更高的性能。在对 BNCT 辐照场中的伽马射线剂量测量进行常规质量保证时，OSLD 系统将成为当前 TLD 系统的合适替代品。

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