ESTRO 2022 - Abstract Book

S12

Abstract book

ESTRO 2022

Results By applying MG4dOPD, the robustness of 4DO plans for motion variability was significantly improved on average by 3.7±4.9% (V95) when DMs were limited within the pre-defined uncertainty bands of ±4mm (Fig.1C and Fig.2B). Further improvements of V95 by 7.0±5.6% can be obtained when additionally incorporating a small number of rescans (VS2) into the 4D optimization. When motion variation was limited to ±4mm, 4DO plans were comparable to the ideal optimized plan quality, with averaged differences of V95 being 3.0±1.2% over all cases. Comparing to the best rescanned 3DO plans (avCT-VS8) (Fig.2B and Fig2C), MG4dOPD improved V95 by 3.3% (1.1-14.4%) in median (range), with best improvements observed for cases with large target and motion.