Dosimetry
The rectal dose constraints for V90% < 15% were fulfilled in 50 out of 52 (96%) patients in MR1 and 47 (90%) patients in MR2 and MR3. Without HA, 46 (88%) patients matched the V90% criteria.Rectal V50%-V90% were significantly reduced in MR1–MR3 compared to MR0. The reduction in V70%/V90% was 56%/69% from MR0 to MR1. Furthermore, the reduction was 31%/30% from MR0 to MR2 and 31%/34% from MR0 to MR3, respectively (Additional file Relative rectal volumes receiving 90% (V90%), 80% (V80%), 70% (V70%), 60% (V60%), and 50% (V50%) of the prescribed dose (78 Gy)