This guide explains the rectal spacer insertion procedure for prostate cancer patients preparing for radiation therapy. It describes how a soft gel spacer is placed between the prostate and rectum to protect the bowel from radiation damage, preventing side effects like rectal bleeding and diarrhea. The material covers pre-procedure preparation including stopping blood thinners and taking laxatives, the one-hour procedure using local anesthesia, recovery instructions, and potential side effects. The spacer dissolves naturally in 3-6 months without requiring removal.