Cine-magnetic resonance imaging assessment of intrafraction motion for prostate cancer patients supine or prone with and without a rectal balloon.

Purpose: Determine prostate intrafraction motion with Cine-magnetic resonance imaging (MRI) and deformable registration.

Methods: A total of 68 cine-MRI studies were done in 17 different series with 4 scans per series in 7 patients. In without rectal balloon (WORB) scans, 100 mL of water was infused in the rectum.