AbstractID: 7516 Title: IMRT Treatment of Prostate Cancer Using 6MV Photon Beam In this work, the clinical results of Intensity Modulated Radiation Therapy (IMRT) treatment for prostate cancer using 6 MV photon beams were reviewed. To treat prostate patients, the conventional 3D conformal treatment was to use high-energy photon beams (10 MV, or higher). In our institute, some of the prostate cases were treated with the existing IMRT system, the PEACOCK/CORVUS system (NOMOS Corp.). A Multileaf Intensity Modulating Collimator (MIMiC) was attached on a Varian 600c LINAC machine, which has a 6 MV single photon beam. The treatment plans were generated by CORVUS Version 3.0. In most cases, the plans included three or four couch movements with gantry rotations from 240 to 120 degrees clockwise. A total of 29 IMRT plans for prostate treatment was reviewed. The median value of V95 for the target, which was the percentage of the target volume covered by 95% dose line, was 99.55%. The median bladder doses were 43.6% below the prescribed target dose, and were 42.6% below the prescribed target dose for the rectum. The coverage of the target doses, and the doses to the critical organs were compared using the IMRT plan and the conventional 3D conformal plans. Our clinical results showed that IMRT with 6 MV photon beams to treat prostate patients provided adequate dose distribution, and satisfied sparser dose to the bladder, the rectum, and the femoral heads. 1