Clinical implementation of PerFRACTION™ for pre-treatment patient-specific quality assurance

This study is to assess the clinical use of commercial PerFRACTION™ for patient-specific quality assurance of volumetric-modulated arc therapy. Forty-six pretreatment verification plans for patients treated using a TrueBeam STx linear accelerator for lesions in various treatment sites such as brain, head and neck (H&N), prostate, and lung were included in this study. All pretreatment verification plans were generated using the Eclipse treatment planning system (TPS). Dose distributions obtained from electronic portal imaging device (EPID), ArcCHECK™, and two-dimensional (2D)/three-dimensional (3D) PerFRACTION™ were then compared with the dose distribution calculated from the Eclipse TPS. In addition, the correlation between the plan complexity (the modulation complexity score and the leaf travel modulation complexity score) and the gamma passing rates (GPRs) of each quality assurance (QA) system was evaluated by calculating Spearman’s rank correlation coefficient ( r s ) with the corresponding p- values. The gamma passing rates of 46 patients analyzed with the 2D/3D PerFRACTION™ using the 2%/2 mm and 3%/3 mm criteria showed almost similar trends to those analyzed with the Portal dose imaging prediction (PDIP) and ArcCHECK™ except for those analyzed with ArcCHECK™ using the 2%/2 mm criterion. Most of weak or moderate correlations between GPRs and plan complexity were observed for all QA systems. The trend of mean r s between GPRs using PDIP and 2D/3D PerFRACTION™ for both criteria and plan complexity indices as in the GPRs analysis was significantly similar for brain, prostate, and lung cases with lower complexity compared to H&N case. Furthermore, the trend of mean r s for 2D/3D PerFRACTION™ for H&N case with high complexity was similar to that of ArcCHECK™ and slightly lower correlation was observed than that of PDIP. This work showed that the performance of 2D/3D PerFRACTION™ for pretreatment patient-specific QA was almost comparable to that of PDIP, although there was small difference from ArcCHECK™ for some cases. Thus, we found that the PerFRACTION™ is a suitable QA system for pretreatment patient-specific QA in a variety of treatment sites.