Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Blvd, Houston, TX, 7030, USA.
Graduate School of Biomedical Sciences, The University of Texas Houston Health Science Center, Houston, TX, USA.
Med Phys. 2019 Aug;46(8):3700-3708. doi: 10.1002/mp.13638. Epub 2019 Jun 23.
To evaluate the performance of an independent recalculation and compare it against current measurement-based patient specific intensity-modulated radiation therapy (IMRT) quality assurance (QA) in predicting unacceptable phantom results as measured by the Imaging and Radiation Oncology Core (IROC).
When institutions irradiate the IROC head and neck IMRT phantom, they are also asked to submit their internal IMRT QA results. Separately from this, IROC has previously created reference beam models on the Mobius3D platform to independently recalculate phantom results based on the institution's DICOM plan data. The ability of the institutions' IMRT QA to predict the IROC phantom result was compared against the independent recalculation for 339 phantom results collected since 2012. This was done to determine the ability of these systems to detect failing phantom results (i.e., large errors) as well as poor phantom results (i.e., modest errors). Sensitivity and specificity were evaluated using common clinical thresholds, and receiver operator characteristic (ROC) curves were used to compare across different thresholds.
Overall, based on common clinical criteria, the independent recalculation was 12 times more sensitive at detecting unacceptable (failing) IROC phantom results than clinical measurement-based IMRT QA. The recalculation was superior, in head-to-head comparison, to the EPID, ArcCheck, and MapCheck devices. The superiority of the recalculation vs these array-based measurements persisted under ROC analysis as the recalculation curve had a greater area under it and was always above that for these measurement devices. For detecting modest errors (poor phantom results rather than failing phantom results), neither the recalculation nor measurement-based IMRT QA performed well.
A simple recalculation outperformed current measurement-based IMRT QA methods at detecting unacceptable plans. These findings highlight the value of an independent recalculation, and raise further questions about the current standard of measurement-based IMRT QA.
评估独立重新计算的性能，并将其与当前基于测量的患者特定强度调制放射治疗（IMRT）质量保证（QA）进行比较，以预测成像和放射肿瘤学核心（IROC）测量的不可接受的体模结果。
当机构辐照 IROC 头颈部 IMRT 体模时，他们还被要求提交他们的内部 IMRT QA 结果。除此以外，IROC 之前已经在 Mobius3D 平台上创建了参考束模型，以便根据机构的 DICOM 计划数据独立重新计算体模结果。将机构的 IMRT QA 预测 IROC 体模结果的能力与自 2012 年以来收集的 339 个体模结果的独立重新计算进行了比较。这样做是为了确定这些系统检测失败体模结果（即大误差）和不良体模结果（即适度误差）的能力。使用常见的临床阈值评估了敏感性和特异性，并使用接收器操作特性（ROC）曲线比较了不同的阈值。
总体而言，基于常见的临床标准，独立重新计算在检测不可接受（失败）IROC 体模结果方面的敏感性比基于临床测量的 IMRT QA 高 12 倍。与 EPID、ArcCheck 和 MapCheck 设备相比，重新计算在头对头比较中具有优势。在 ROC 分析中，重新计算与这些基于阵列的测量相比具有优势，因为重新计算曲线下的面积更大，并且始终高于这些测量设备。对于检测适度误差（不良体模结果而不是失败体模结果），重新计算和基于测量的 IMRT QA 都表现不佳。
简单的重新计算在检测不可接受的计划方面优于当前基于测量的 IMRT QA 方法。这些发现突出了独立重新计算的价值，并进一步提出了关于当前基于测量的 IMRT QA 标准的问题。
