中华放射医学与防护杂志

张毅,羊奕伟,唐瑛鸿,等.基于EBT4胶片的FLASH放疗快速精确剂量测量研究与应用[J].中华放射医学与防护杂志,2025,45(11):1144-1151.Zhang Yi,Yang Yiwei,Tang Yinghong,et al.A study and application of rapid and precise dose measurement based on Gafchromic EBT4 film in FLASH radiotherapy[J].Chin J Radiol Med Prot,2025,45(11):1144-1151

基于EBT4胶片的FLASH放疗快速精确剂量测量研究与应用

A study and application of rapid and precise dose measurement based on Gafchromic EBT4 film in FLASH radiotherapy

投稿时间：2025-07-10

DOI：10.3760/cma.j.cn112271-20250710-00246

中文关键词: 超高剂量率(FLASH)放疗 EBT胶片 RGB值净光密度

英文关键词:FLASH radiotherapy EBT film RGB value Net optical density

基金项目:国家自然科学基金(12375318);贵州省抗癌协会科技计划项目([2023]015)

作者	单位	E-mail
张毅	贵州医科大学附属医院贵州医科大学附属肿瘤医院肿瘤科, 贵阳 550024
羊奕伟	中国工程物理研究院应用电子学研究所, 绵阳 621900
唐瑛鸿	成都理工大学核技术与自动化工程学院, 成都 610000
王诗岚	中国工程物理研究院应用电子学研究所, 绵阳 621900
吴鹏	中玖闪光医疗科技有限公司电气电控/临床部, 绵阳 621000
杨沁	中玖闪光医疗科技有限公司电气电控/临床部, 绵阳 621000
黄旭帆	中玖闪光医疗科技有限公司电气电控/临床部, 绵阳 621000
罗银	中玖闪光医疗科技有限公司电气电控/临床部, 绵阳 621000
蒋雨	中玖闪光医疗科技有限公司电气电控/临床部, 绵阳 621000
罗文俊	中玖闪光医疗科技有限公司电气电控/临床部, 绵阳 621000
邹贵强	中玖闪光医疗科技有限公司电气电控/临床部, 绵阳 621000
冯化	中玖闪光医疗科技有限公司电气电控/临床部, 绵阳 621000
胡银祥	贵州医科大学附属医院贵州医科大学附属肿瘤医院肿瘤科, 贵阳 550024 贵州医科大学临床医学院肿瘤学教研室, 贵阳 55000	hyx_wengan@163.com

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中文摘要:

目的针对辐射变色胶片在FLASH照射条件下测量时效性和准确性较差的两大核心问题, 建立一种EBT4胶片的快速精确剂量测量方法, 并通过严格操作过程确保测量精度在要求范围内。方法将胶片在不同湿度条件下保存一定时间后进行照射, 分析空气湿度对EBT胶片本征性能影响。进行重复扫描操作以及旋转胶片角度, 分析重复扫描和胶片放置角度影响。使用抛物线修正方法减小扫描过程空间位置(横向/纵向)影响。通过3种拟合方式比较净光密度(netOD)和吸收剂量之间的关系, 选取最优拟合曲线。同一批次胶片照射后5 min和24 h胶片剂量刻度并与电离室测量结果对比分析。使用胶片快速精确剂量测量方法应用于超高剂量率X射线的百分深度剂量和2 cm水深度下的剂量分布。结果空气湿度对EBT胶片本征性能影响最大接近20%;重复扫描平均偏差在0.5%以内;胶片放置角度会显著影响胶片读取结果(最大影响接近70%);使用netOD配合多项式拟合可将1~16 Gy的拟合残差控制在3%以内。5 min时绝大多数光通道的变化率已经满足快速模式的要求(< 0.5%)。5 min及24 h剂量标定曲线的测量结果与参考级电离室的测量结果的相对偏差均在2%以内。结论通过严格控制变量, EBT4胶片可用于快速精确的FLASH剂量测量, 可以满足FLASH临床前甚至临床研究的要求。

英文摘要:

Objective To establish a rapid and precise dose measurement method with EBT4 film and ensure its measurement accuracy to be within the required range through strict operational procedures for the purpose of addressing the two essential issues of poor measurement accuracy and timeliness of EBT film under FLASH conditions. Methods After storing under different humidity conditions for a certain period of time, the film was exposed to radiation for analyzing the influence of air humidity on the intrinsic performance of EBT film. By means of repeated scanning operations and the film angle rotation, the influences of repeated scanning and film placement angle were analuzed. Parabolic correction method was used to reduce the spatial position influence during the scanning process. By analying the relationship between net optical density (netOD) and absorbed dose through the comparison of three fitting method, the optimal fitting curve was selected. After irradiation of the same batch of films for 5 min and 24 h, the film doses were calibrated and then compared with ionization chamber-measured result. The rapid and precise film dosimetry method was used to measure both the percentage depth dose from X-rays at ultra-high dose rate and the dose distribution at a depth of 2 cm in water. Results Air humidity had the greatest influence on the intrinsic performance of EBT film (approximately 20%). The average deviation of repeated scans is within 0.5%. The angle at which the film is placed significantly affected the readouts of the film with the maximum influence approximately 70%. The net optical density combined with polynomial fitting can control the fitting residuals of 1-16 Gy within 3%. The change rate of light channels at 5 min already mostly met the requirements of the rapid mode (< 0.5%). Compared with the measurement result obtained using the reference ionization chamber, the deviations of the 5 min or 24 h dose calibration curves were all within 2%. Conclusions The EBT4 film can be employed as a precise dosimeter to quickly measure the FLASH radiation dose. Rapid and precise FLASH dose measurements can meet the stringent requirements of both preclinical and clinical FLASH research.

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