SpaceOAR Hydrogel is an option for men who undergo radiation treatment for prostate cancer. It acts as a spacer providing space between the rectum and the prostate, reducing radiation exposure to the rectum. It is injected into place prior to the start of radiation treatment. Patients may be awake or asleep under general anesthesia for the procedure. SpaceOAR Hydrogel remains stable during radiation therapy and then is gradually absorbed by the body after radiation therapy has been completed.