 This study follows a pilot study in which patients receiving RT were shown how treatment is planned and given using a 3 dimensional 3D imaging system. It was noticed that patients with prostate cancer entering the pilot study might have been more compliant holding water before each treatment session than those with prostate cancer not entering the study. On this basis, the investigators wish to run this project in which prostate cancer patients will be shown how RT is planned and given using 3D images prior to start RT study arm, 170 patients or after completion of RT controlstandard arm, 170 patients. A sample size calculation was performed see below in order to distinguish a 10 improvement in retention of bladder volume over the course of treatment. 