Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg, Baden-Wurttemberg, Germany.
Heidelberg Institute of Radiation Oncology (HIRO), National Center for Radiation Oncology (NCRO), Heidelberg, Baden-Wurttemberg, Germany.
J Appl Clin Med Phys. 2022 Mar;23(3):e13523. doi: 10.1002/acm2.13523. Epub 2022 Jan 12.
Online adaption of treatment plans on a magnetic resonance (MR)-Linac enables the daily creation of new (adapted) treatment plans using current anatomical information of the patient as seen on MR images. Plan quality assurance (QA) relies on a secondary dose calculation (SDC) that is required because a pretreatment measurement is impossible during the adaptive workflow. However, failure mode and effect analysis of the adaptive planning process shows a large number of error sources, and not all of them are covered by SDC. As the complex multidisciplinary adaption process takes place under time pressure, additional software solutions for pretreatment per-fraction QA need to be used. It is essential to double-check SDC input to ensure a safe treatment delivery. Here, we present an automated treatment plan check tool for adaptive radiotherapy (APART) at a 0.35 T MR-Linac. It is designed to complement the manufacturer-provided adaptive QA tool comprising SDC. Checks performed by APART include contour analysis, electron density map examinations, and fluence modulation complexity controls. For nine of 362 adapted fractions (2.5%), irregularities regarding missing slices in target volumes and organs at risks as well as in margin expansion of target volumes have been found. This demonstrates that mistakes occur and can be detected by additional QA measures, especially contour analysis. Therefore, it is recommended to implement further QA tools additional to what the manufacturer provides to facilitate an informed decision about the quality of the treatment plan.
在线适应治疗计划在磁共振（MR）-直线加速器上，可以使用当前患者的解剖学信息（在 MR 图像上看到）每天创建新的（适应的）治疗计划。计划质量保证（QA）依赖于二次剂量计算（SDC），因为在自适应工作流程中不可能进行预处理测量。然而，自适应计划过程的失效模式和影响分析显示出大量的误差源，而且并非所有误差源都被 SDC 覆盖。由于复杂的多学科适应过程是在时间压力下进行的，因此需要使用额外的预处理分次 QA 软件解决方案。仔细检查 SDC 输入以确保安全治疗是至关重要的。在这里，我们在 0.35 T MR-直线加速器上为自适应放射治疗（APART）展示了一种自动化治疗计划检查工具。它旨在补充制造商提供的自适应 QA 工具，包括 SDC。APART 执行的检查包括轮廓分析、电子密度图检查和通量调制复杂度控制。在 362 个自适应部分中的 9 个（2.5%）中，发现目标体积和风险器官的缺失切片以及目标体积的边缘扩展方面存在不规则情况。这表明错误确实会发生，并且可以通过额外的 QA 措施检测到，尤其是轮廓分析。因此，建议实施制造商提供的额外 QA 工具，以协助做出有关治疗计划质量的知情决策。
