Clinical feasibility of patient-specific head and neck VMAT QA in high-volume practice: workflow efficiency analysis and gamma-based agreement between cylindrical 3D diode detector array and portal dosimetry

Background: This retrospective study examines the workflow efficiency and gamma analysis outcomes of ArcCHECK TM (Sun Nuclear Corporation, Melbourne, FL, USA) and EPIbeam TM (DOSIsoft, Cachan, France) portal dosimetry for verifying head and neck volumetric modulated arc therapy (VMAT) treatment plans, with an emphasis on their suitability for high-volume radiotherapy facilities. Materials and methods: Thirty-two head and neck VMAT plans were retrospectively analysed. The Elekta Versa HDTM (Elekta, Stockholm, Sweden) and Monaco TM treatment planning system (TPS) were used to generate all plans. Workflow times were documented, and gamma analysis was carried out using multiple criteria (3%/3 mm to 1%/1 mm). Statistical comparisons included mean differences, correlation coefficients and paired t-tests. Results: Both EPIbeam TM and ArcCHECK TM performed well under the 3%/3 mm and 3%/2 mm criteria. However, EPIbeam TM portal dosimetry required less setup time, supporting improved throughput in high-volume settings. Higher mean gamma pass rates were observed with EPIbeam TM in both patient groups. For the 3%/3 mm and 3%/2 mm criteria, respectively, ArcCHECK TM achieved 98.32% ± 1.03% and 96.33% ± 2.11%, whereas EPIbeam TM achieved 99.93% ± 0.09% and 99.70% ± 0.40%. The differences were statistically significant (p < 0.01) and the low correlation coefficients indicated that the two systems respond differently to complex head and neck plans. Conclusions : Utilising both systems at different stages, depending on the requirements and device-specific tolerances, can strengthen the overall QA process and provide an added layer of confidence.