Dosimetric Comparison of Four Commercial Patient-Specific Quality Assurance Devices for Helical Tomotherapy

In this study, the delivery quality assurance (DQA) results of commercially available dosimetric systems (ionization chamber and EBT film, MapCHECK, ArcCHECK, and dosimetry check (DC) software) for helical tomotherapy (HT) were compared, and the feasibility of performing pretreatment using MapCHECK, ArcCHECK, and DC for HT, instead of ionization chambers and EBT films, was assessed. Sixty-five HT-treated patients were considered. Point dose differences, dose profiles, and gamma passing rates were used to evaluate the agreement between the calculated and the measured data, and the outcomes of the four DQA devices were compared in various clinical cases. The calculated and the measured point doses were within ±5% of each other. In terms of the root-mean-square error (RMSE), the point dose differences were within 2.9 for the four tested devices in all of the studied cases. Gamma analysis was performed based on the 3%/3 mm and 2%/2 mm passing rate criteria. In terms of the average RMSE, the gamma passing rates of the four tested DQA devices were within 2.85 (3%/3 mm) and 7.30 (2%/2 mm). These DQA systems could be used interchangeably for routine DQA pretreatment in HT cases.