Application of stereotactic body radiotherapy planning verification phantom in HyperArc technique for brain metastases / 中华放射医学与防护杂志

ABSTRACT

Objective:To explore the feasibility of StereoPhan (SP) phantoms and SRS MapCHECK (SMC) semiconductor matrices in the dose verification of HyperArc (HA) plans for patients with brain metastases (BM).Methods:A total of 16 BM patients who received HA radiotherapy in the Peking Union Medical College Hospital were enrolled in this study. The ion chamber and the SMC semiconductor matrix were inserted into SP phantoms, respectively. The point and planar doses in HA verification plans were measured and compared with the calculated data of the treatment planning system (TPS). The criteria for planar dose γ analysis were set at 2 mm/3%, 2 mm/2%, 1 mm/3%, and 1 mm/2%.Results:The mean deviation of point doses in 16 patients was 1.33%±0.84%. Based on the above criteria, the γ pass rates of planar doses were 99.72%±0.46%, 98.93%±1.32%, 98.85%±1.79%, and 97.13%±3.19%, respectively.Conclusions:SP phantoms and SMC semiconductor matrices are applicable to the dose verification of HA plans for BM patients. The analytical criteria of 3% and 1 mm/2% can be used for verifying point and planar doses, respectively.