The effect of an endorectal balloon and off-line correction on the interfraction systematic and random prostate position variations: A comparative study

The off-line corrections on the fiducial markers are effective in reducing the systematic prostate displacements. The investigated ERB does not reduce the interfraction prostate motion. Although the overall mean displacement is low, the day-to-day interfraction motion, especially in anterior-posterior direction, remains high compared with the systematic displacements.