The new function of 3DVH software for dose calculation inside the patient undergoing TomoTherapy treatment by applying the measured data obtained by ArcCHECK was recently released. In this study, the dosimetric accuracy of 3DVH for the TomoTherapy DQA process was evaluated by the comparison of measured dose distribution with the dose calculated using 3DVH. The 2D diode detector array MapCHECK phantom was used for the TomoTherapy planning of virtual patient and for the measurement of the compared dose. The average pass rate of gamma evaluation between the measured dose in the MapCHECK phantom and the recalculated dose in 3DVH was 92.6±3.5%, and the error was greater than the average pass rate, 99.0±1.2%, in the gamma evaluation results with the dose calculated in TomoTherapy planning system. The error was also greater than that in the gamma evaluation results in the RapidArc analysis, which showed the average pass rate of 99.3± 0.9%. The evaluated accuracy of 3DVH software for TomoTherapy DQA process in this study seemed to have some uncertainty for the clinical use. It is recommended to perform a proper analysis before using the 3DVH software for dose recalculation of the patient in the TomoTherapy DQA process considering the initial application stage in clinical use.

Keywords3DVH, TomoTherapy, Delivery quality assurance (DQA), ArcCHECK, RapidArc