ESTRO 2024 - Abstract Book

S4214

Physics - Intra-fraction motion management and real-time adaptive radiotherapy

ESTRO 2024

The derived population PTV margins are smaller in all directions, with greatest different in the ANT and SUP directions. The PTV volume reduced by a mean of 26%

Only 3 of 20 patients (15%) had smaller PTV volume using the bespoke margins.

The PTV coverage remained unchanged between plans. Dose to the rectum and bowel was lowest on average with population margins. The rectum V52Gy and V43Gy reduced by 71% and 45% respectively when using population margins. The bowel dose also significantly reduced as seen in Figure 2 with V52Gy reducing by 45% (48.5cc to 26.3cc). Doses delivered using bespoke margins on average were between the IGRT and population margins, but varied significantly between patients.