A recent found remarkable reduction in bowel and urinary side effects when MRI was used instead of CT to guide stereotactic body radiotherapy (SBRT) for localised prostate cancer. The observational study by a team of researchers at the University of California and presented at the American Society of Clinical Oncology Genitourinary Cancers Symposium, analysed 100 men in the phase 3 MIRAGE trial (Magnetic Resonance Imaging–Guided v/s Computed Tomography–Guided Stereotactic Body Radiotherapy for Prostate Cancer), MRI guidance more than halved the incidence of grade 2 or higher physician-reported genitourinary toxicity within 90 days of the procedure, which fell from 47.1 percent with CT to 22.4 percent with MRI.

While 13.7% of men had gastrointestinal complications with CT guidance, there wasn’t a single case in the MRI arm.