Watch Dr. Eric Giesler, Urologist at Urology Austin and Dr. Niraj Pahlajani, Radiation Oncologist at the Austin Center for Radiation Oncology, host a webinar on prostate cancer, prostate cancer treatments including Radiation Therapy, and SpaceOAR. SpaceOAR - or Organ at Risk. SpaceOAR is a hydrogel that is injected between the prostate gland and rectum to protect the rectum from radiation exposure during treatments.