Intensity Modulated Radiation Therapy (IMRT) is a high precision 3D radiotherapy that uses computer controlled linear accelerators to deliver the radiation to the tumor or to specific areas of the tumor. The IMRT treatment allows high doses of radiation to be administered to the tumor or to regions within the tumor while minimizing the dose to surrounding tissue and organs. A computer moves around the patient while delivering beams of radiation that comes from different angles and intensities to produce a custom radiation dose to the prostate tumor.