Beam complexity and monitor unit efficiency comparison in two different volumetric modulated arc therapy delivery systems using automated planning

Abstract Background To investigate the beam complexity and monitor unit (MU) efficiency issues for two different volumetric modulated arc therapy (VMAT) delivery technologies patients with left-sided breast cancer (BC) nasopharyngeal carcinoma (NPC). Methods Twelve BC seven NPC cases were enrolled in this study. Each delivered treatment plan was optimized Pinnacle 3 planning system Auto-Planning module Trilogy Synergy systems. Similar dose objectives configurations used each site systems to produce clinically acceptable plans. The evaluated terms of segment area (SA), width (SW), leaf sequence variability (LSV), aperture (AAV), modulation score (MCS) based on multileaf collimator MU. Plan a gamma evaluation performed using helical diode array. Results With similar quality, average SAs plans smaller than those plans: 55.5 ± 21.3 cm 2 vs. 66.3 17.9 ( p < 0.05) 100.7 49.2 108.5 42.7 cases, respectively. SW statistically significant (NPC: 6.87 1.95 6.72 2.71 cm, 0.05; BC: 8.84 2.56 8.09 2.63 0.05). LSV significantly 0.84 0.033 0.86 0.033, 0.89 0.026 0.90 0.26, mean AAV larger 0.18 0.064 0.14 0.037, 0.46 0.15 0.33 0.13, MCS values higher Synergy: 0.016 0.12 0.017 0.42 0.106 0.30 0.087 cases. Compared plans, MUs larger: 828.6 74.1 MU 782.9 85.2 > 444.8 61.3 393.8 75.3 index agreement scores never below 91% mm/3% (global) distance difference criteria 10% lower exclusion threshold. Conclusions can optimize achieve same quality both We found that these resulted SAs, SWs, LSVs, AAVs MCSs. As result, we suggested should be considered development further methodologies while optimizing VMAT autoplanning.