A patient-specific QA comparison between 2D and 3D diode arrays for single-lesion SRS and SBRT treatments

The purpose of this study is to compare patient-specific quality assurance (PSQA) results between two dimensional (2D) diode (SRS MapCHECK (R)) and 3D diode (ArcCHECK (R)) arrays. Twenty-eight intracranial stereotactic radiosurgery (SRS) and 26 lung stereotactic body radiation therapy (SBRT) clinical plans with a single lesion were selected and categorized into 4 groups: 20 SRS dynamic conformal arc therapy (DCAT) plans (Group A), 8 SRS volumetric modulated arc therapy (VMAT) plans (Group B), 6 SBRT DCAT plans (Group C) and 20 SBRT VMAT plans (Group D). An individual field of each plan was delivered on SRS MapCHECK and ArcCHECK and QA analysis was performed using 4 gamma criteria of dose difference/distance-to-agreement of 3%/3 mm, 3%/2 mm, 2%/2 mm and 2%/1 mm. Statistical analysis was performed to compare PSQA results between the 2 QA devices. For all 4 groups and all 4 gamma criteria, average gamma passing rates were higher with SRS MapCHECK.