Practical experience in commissioning ring applicators using ring applicator component type with bravos control software v1.2.

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

Journal of Applied Clinical Medical Physics Pub Date : 2025-05-02 DOI:10.1002/acm2.70064

Xiuxiu He, Michael A Trager, Gil'ad N Cohen, Antonio L Damato, David Aramburu Núñez

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引用次数: 0

Abstract

Purpose: The Bravos v1.2 control software introduces a ring applicator component type (ACT) with channel length verification to address geometric characteristics and dosimetric discrepancies caused by source positioning inaccuracies. This study aims to commission the ring applicator and investigate the new ring ACT in Bravos 1.2.

Material and methods: We evaluated two commissioning methods for a CT/MRI-compatible titanium ring applicator across three Bravos afterloaders and compared the new ring ACT with the traditional rigid ACT. Modifications to Varian's standard commissioning method included: (1) Delivering film plans with a 0.5 cm step size instead of 1 cm; (2) Alternating 0.3 s and 1 s dwell positions for enhanced source positioning analysis; (3) Including both "odd" and "even" positions to replicate clinical conditions. Films for 30-, 45-, and 60-degree rings (3.2 cm diameter) were delivered using modified methods and manual offsets of 0.0 cm, 0.1 cm, and 0.2 cm. Discrepancies between delivered and planned positions were analyzed, and the optimal offset was validated using clinical plans. Dosimetric differences for various gross tumor volumes (GTVs) and organs at risk (OARs) were assessed.

Results: Film analysis (216 films) identified 0.2 cm as the optimal offset for all rings and afterloaders, minimizing deviations between the planned and delivered dwell positions. The rigid ACT showed larger discrepancies. The optimal offset reduced physical dosimetric differences to < 1% for key clinical metrics (D95, D90, D2cc) across all angles, with negligible differences in EQD2 values.

Conclusion: A novel commissioning procedure was developed to determine an optimal offset for accurate source positioning and minimize dosimetric discrepancies with the ring ACT. This method improves accuracy compared to the rigid ACT and standardizes commissioning for Bravos afterloaders with the v1.2 control system.

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使用带有bravos控制软件v1.2的环形涂抹器组件类型调试环形涂抹器的实践经验。

目的：Bravos v1.2控制软件引入了带通道长度验证的环形涂抹器组件类型（ACT），以解决由源定位不准确引起的几何特性和剂量学差异。本研究旨在委托戒指涂抹器并研究Bravos 1.2中的新戒指ACT。材料和方法：我们评估了CT/ mri兼容钛环涂抹器在三个Bravos后装器上的两种调试方法，并将新型环ACT与传统刚性ACT进行了比较。对瓦里安标准调试方法的修改包括：(1)提供步长为0.5 cm而不是1 cm的薄膜方案；(2)交替0.3 s和1 s驻留位置，增强源定位分析；(3)包括“奇数”位和“偶数”位，以复制临床情况。30度、45度和60度环（3.2 cm直径）的薄膜采用改进的方法和手动偏移量分别为0.0 cm、0.1 cm和0.2 cm。分析交付位置和计划位置之间的差异，并使用临床计划验证最佳偏移量。评估了不同总肿瘤体积（gtv）和危险器官（OARs）的剂量学差异。结果：胶片分析（216片）确定0.2 cm为所有环和后装载机的最佳偏移量，最大限度地减少了计划和交付的停留位置之间的偏差。严格的ACT显示出更大的差异。结论：开发了一种新的调试程序，以确定准确源定位的最佳偏移量，并最大限度地减少与环形ACT的剂量差异。与严格的ACT相比，这种方法提高了精度，并使带有v1.2控制系统的Bravos后装载机的调试标准化。

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