Rojas-López José Alejandro, Cabrera-Santiago Alexis, Corral-Beltrán Jorge Ramiro, García-Andino Albin Ariel
Department of Radiotherapy, Hospital Angeles Puebla, Av. Kepler, Reserva Territorial Atlixcáyotl, Puebla, México.
Department of Physics, Faculty of Astronomy, Mathematics, Physics and Computing, National University of Córdoba, Av. Medina Allende, X5000 Córdoba, Argentina.
J Med Phys. 2025 Jan-Mar;50(1):20-29. doi: 10.4103/jmp.jmp_150_24. Epub 2025 Mar 24.
The purpose of this study was to report the commissioning the secondary dose calculation software ThinkQA (TQA) for an magnetic resonance-guided linear accelerator (MR-linac).
The Medical Physics Practice Guideline 5.a. (MPPG5a) tests, and dose in inhomogeneities, beam profiles, and depth dose curves were calculated and compared between Monaco and TQA. Five intensity modulated radiotherapy (IMRT) plans (anal, abdominal, head and neck, prostate, and lung), based on TG-244 guidelines were evaluated varying the gamma criteria. Furthermore, the initial and adapted plans for the first session for 17 patients in different anatomical regions were calculated in TQA using different gamma criteria. For five patients, six measurements were made at different fractions using ArcCheck and compared with TQA.
The majority of tests met the tolerances defined in the MPPG5a with the exception of dose profiles (>10%), and large multileaf collimator-shaped fields with extensive blocking (>2%). For the IMRT plans, tight criteria such as 2%/2 mm may not be suitable for all scenarios. Thus, we adopt a reasonable 3%/2 mm without compromising the quality of the plan that included significant high-to-low-density interfaces. It is observed that, the values obtained for clinical cases are in the range from 94.6% to 99.8% (TQA), 97.0% to 99.6% (ArcCheck), except in a prostate case with 87.8% (TQA) and 99.3% (ArcCheck).
We commissioned TQA as a secondary dose calculation for MR-linac and we introduced it clinically for adaptive treatment workflow using 3%/2 mm with 95% as tolerance limit and 90% as action limit.
本研究旨在报告用于磁共振引导直线加速器（MR直线加速器）的二次剂量计算软件ThinkQA（TQA）的调试情况。
按照医学物理实践指南5.a.（MPPG5a）进行测试，并计算了Monaco和TQA之间的不均匀性剂量、射野轮廓和深度剂量曲线并进行比较。基于TG-244指南评估了五个调强放射治疗（IMRT）计划（肛管、腹部、头颈部、前列腺和肺部），改变了伽马标准。此外，使用不同的伽马标准在TQA中计算了17例不同解剖区域患者首次治疗的初始计划和调整计划。对五名患者，在不同分次使用ArcCheck进行了六次测量，并与TQA进行比较。
除剂量轮廓（>10%）和具有广泛遮挡的大型多叶准直器形状射野（>2%）外，大多数测试符合MPPG5a中定义的公差。对于IMRT计划，诸如2%/2 mm这样严格的标准可能并不适用于所有情况。因此，我们采用了合理的3%/2 mm，而不影响包含显著高低密度界面的计划质量。观察到，临床病例获得的值在94.6%至99.8%（TQA）、97.0%至99.6%（ArcCheck）范围内，但有一例前列腺病例除外，该病例TQA为87.8%，ArcCheck为99.3%。
我们将TQA调试为MR直线加速器的二次剂量计算软件，并将其临床引入自适应治疗工作流程，使用3%/2 mm，以95%作为公差限值，90%作为行动限值。
