Adenocarcinoma of the prostate will affect over 220,900 U.S. males this year, making it the most prevalent cancer in the nation.1 Prostate specific antigen (PSA) is a very useful tumor marker in early detection of this malignancy, as well as a reliable marker for control after definitive therapy with either surgery or irradiation.2,3,4 Widespread use of prostate-specific antigen (PSA) screening has resulted in approximately 45% of patients being detected with early stage disease. For this group of patients, brachytherapy or implantation of radioactive sources into the prostate is a treatment option that has risen dramatically in use over the last several years due to its effectiveness and convenience.5 The use of brachytherapy or implantation of radioactive sources into the prostate for adenocarcinoma has advantages over external beam radiation in that a very high dose can be delivered to the tumor while limiting the doses to the surrounding normal tissue (i.e., bowel and bladder). It is well established that outcomes after treatment with brachytherapy are critically related to the technical quality of source placement within the gland. A spatially desirable placement of the radioactive sources with achievement of optimum dose distributions within the prostate is key to the success of brachytherapy with regard to both killing tumor as well as minimizing toxicity.6,7,8 The development of transrectal ultrasound (TRUS) of the prostate, with the ability to map the prostate in several planes, as well as the associated development of trans-perineal implantation of the prostate, has allowed the development of the modern prostate implantation method. Ultrasound images are taken before or during the implant procedure, and a source distribution plan is developed that optimizes dose to the prostatic tissues while sparing the urethra and rectum. Needles are placed into the prostate via a transperineal template, and the sources are placed into the prostate according to the source distribution plan.