| 武益名,杜晓宏,李琳,等.笔形束扫描质子放疗系统束斑等中心性能检测方法学研究[J].中华放射医学与防护杂志,2026,46(8):763-768.Wu Yiming,Du Xiaohong,Li Lin,et al.A methodological study on spot isocenter performance verification for pencil beam scanning proton radiotherapy systems[J].Chin J Radiol Med Prot,2026,46(8):763-768 |
| 笔形束扫描质子放疗系统束斑等中心性能检测方法学研究 |
| A methodological study on spot isocenter performance verification for pencil beam scanning proton radiotherapy systems |
| 投稿时间：2025-11-21 |
| DOI：10.3760/cma.j.cn112271-20251121-00407 |
| 中文关键词: 质子治疗|质量控制|EBT4胶片|等中心束斑分析模体 |
| 英文关键词:Proton therapy|Quality control|EBT4 radiochromic film|Phantom for isocentric spot analysis |
| 基金项目:北京市自然科学基金(L2602050) |
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| 中文摘要: |
| 目的 评估自主设计等中心束斑分析模体结合EBT4胶片在多机架角度下测量束斑等中心偏差的可行性,建立一种适用于笔形束扫描(PBS)质子放疗系统的束斑等中心质量控制方法。方法 针对该模体在非水平、垂直机架角度下难以与现有二维矩阵探测器联用的问题,引入 EBT4胶片测量束斑等中心与治疗室定位光中心之间的偏差。采用紫外-可见分光光度计确定胶片分析的色彩通道,并建立标准化的图像分析流程及参数选取原则。分别在不同机架角度下进行照射测量,分析束斑中心与定位光中心之间的空间偏差。结果 不同机架角度下的实验结果表明,自主设计模体与EBT4胶片联合应用可精确分辨束斑中心与治疗室定位光中心之间的偏差。测得最大偏差为0.88 mm,低于《医用质子重离子放射治疗设备质量控制检测标准》(WS 816-2023)中1 mm的标准限值。结论 本方法满足WS 816-2023中"辐射束等中心偏差"质量控制指标要求,尤其适用于PBS质子放疗系统多机架角度下的等中心验证,可为质子治疗中心建立标准化、可复现的质量控制流程提供方法学参考。 |
| 英文摘要: |
| Objective To assess the feasibility of the combination of an self-designed phantom for isocentric spot analysis and EBT4 radiochromic films in measuring spot isocenter deviations at multiple gantry angles, and to establish a method for quality control (QC) of spot isocenter that is suitable for pencil beam scanning (PBS) proton radiotherapy systems. Methods To address the incompatibility between the designed phantom and existing two-dimensional array detectors at non-horizontal and non-vertical gantry angles, EBT4 radiochromic films were introduced to measure the deviations between the spot isocenter and the patient positioning laser isocenter in the radiotherapy room. The optimal color channel for film readout was determined using an ultraviolet-visible (UV-Vis) spectrophotometer, followed by the establishment of a standardized image analysis workflow and guidelines for parameter selection. Irradiation measurements were performed at varying gantry angles, and the spatial deviation between the spot isocenter and the positioning laser isocenter was analyzed. Results Experimental measurements at varying gantry angles indicated that the combination of the independently designed phantom and EBT4 radiochromic films can accurately identify the deviations between the spot isocenter and the positioning laser isocenter. The maximum deviation measured 0.88 mm, below the tolerance limit of 1 mm specified in the Standard for testing of quality control in medical proton/heavy ion radiotherapy equipment (WS 816-2023) Conclusions The proposed method meets the QC requirements for radiation-beam isocenter deviations specified in WS 816-2023. This method is particularly suitable for isocenter verification in PBS proton therapy systems under varying gantry angles, providing a method ological reference for proton therapy centers to establish standardized and reproducible QC workflows. |
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