An in‐house trajectory log analysis program (LOGQA) was developed to evaluate the delivery accuracy of volumetric‐modulated arc therapy (VMAT) for stereotactic body radiation therapy (SBRT). Methods have been established in LOGQA to provide analysis on dose indices, gantry angles, and multi‐leaf collimator (MLC) positions. Between March 2019 and May 2020, 120 VMAT SBRT plans of various treatment sites using flattening filter‐free (FFF) mode were evaluated using both LOGQA and phantom measurements. Gantry angles, dose indices, and MLC positions were extracted from log and compared with each plan. Integrated transient fluence map (ITFM) was reconstructed from log to examine the deviation of delivered fluence against the planned one. Average correlation coefficient of dose index versus gantry angle and ITFM for all patients were 1.0000, indicating that the delivered beam parameters were in good agreement with planned values. Maximum deviation of gantry angles and monitor units (MU) of all patients were less than 0.2 degree and 0.03 % respectively. Regarding MLC positions, maximum and root‐mean‐square (RMS) deviations from planned values were less than 0.6 mm and 0.3 mm respectively, indicating that MLC positions during delivery followed planned values in precise manner. Results of LOGQA were consistent with measurement, where all gamma‐index passing rates were larger than 95 %, with 2 %/2 mm criteria. Three types of intentional errors were introduced to patient plan for software validation. LOGQA was found to recognize the introduced errors of MLC positions, gantry angles, and dose indices with magnitudes of 1 mm, 1 degree, and 5 %, respectively, which were masked in phantom measurement. LOGQA was demonstrated to have the potential to reduce or even replace patient‐specific QA measurements for SBRT plan delivery provided that the frequency and amount of measurement‐based machine‐specific QA can be increased to ensure the log files record real values of machine parameters.

中文翻译：

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使用机器日志文件分析进行立体定向放射治疗 (SBRT) 的患者特定质量保证

开发了一个内部轨迹日志分析程序 (LOGQA) 来评估体积调制弧治疗 (VMAT) 用于立体定向放射治疗 (SBRT) 的输送准确性。已在 LOGQA 中建立了方法来提供剂量指数、机架角度和多叶准直器 (MLC) 位置的分析。在 2019 年 3 月至 2020 年 5 月期间，使用 LOGQA 和体模测量评估了使用扁平化无滤波器 (FFF) 模式的不同治疗部位的 120 个 VMAT SBRT 计划。从日志中提取机架角度、剂量指数和 MLC 位置，并与每个计划进行比较。综合瞬态注量图 (ITFM) 从日志中重建，以检查传递的注量与计划注量的偏差。所有患者的剂量指数与机架角度和 ITFM 的平均相关系数为 1.0000，表明交付的光束参数与计划值非常一致。所有患者的机架角度和监视器单位（MU）的最大偏差分别小于0.2度和0.03%。关于 MLC 位置，与计划值的最大和均方根 (RMS) 偏差分别小于 0.6 mm 和 0.3 mm，表明 MLC 位置在交付过程中以精确的方式遵循计划值。LOGQA 的结果与测量结果一致，所有 gamma 指数通过率均大于 95 %，标准为 2 %/2 mm。软件验证的患者计划中引入了三种类型的故意错误。发现 LOGQA 可以识别 MLC 位置、机架角度和剂量指数的引入误差，幅度分别为 1 mm、1 度和 5%，在体模测量中被掩盖。如果可以增加基于测量的机器特定 QA 的频率和数量，以确保日志文件记录机器参数的真实值，则 LOGQA 被证明有可能减少甚至替代 SBRT 计划交付的患者特定 QA 测量。