Evaluation of Radiation Therapy Positioning System (RTPS) in Patients With Localized Prostate Cancer

Inclusion Criteria: 1. Diagnosis of adenocarcinoma of the prostate. 2. Male, age greater than or equal to 45 years. 3. Intact prostate of at least 30g, as estimated by physical estimation and/or ultrasound. 4. ECOG (Eastern Cooperative Oncology Group) performance status of 0 or 1. 5. Patients must be planned to have external beam radiation as the definitive treatment for their prostate cancer with treatment set-up verification according to a locally fixed protocol. 6. Patients must have anatomy that will allow an adequate pelvic imaging by CBCT as well as CT scanning. 7. Organ confined or locally advanced prostate cancer with clinical N category 0 or x, M category 0 or x. 8. Ability to comply with study visit schedule. 9. Patient (or legal guardian) understands the study requirements and the investigational procedure and provides written Informed Consent before any study-specific tests or procedures are performed. Exclusion Criteria: 1. Past history of abdominoperineal (A-P) resection. 2. Planned course of treatment using brachytherapy (permanent brachytherapy seeds or high dose rate \[HDR\] brachytherapy). 3. Allergy to local anesthetics. 4. History of chronic prostatitis. 5. Patients with history of recent acute and/or chronic bleeding disorders. 6. Patients on therapeutic anti-coagulants or anti-platelet therapy, not including aspirin or dipyridamole. 7. Patients for which the maximum body width or the maximum anterior-posterior depth in the abdomino-pelvic region is greater than 40 cm. (Measurements will be made visually with a ruler.) 8. Patients with a body habitus that the CT bore of the CT/LINAC treatment machine cannot accommodate. 9. Patients with a prior history of pelvic or prostate radiotherapy. 10. Patients who have had prior prostate surgery other than a TUR. 11. Cognitively impaired patients who cannot give informed consent. 12. Patients with hip replacement by a metal prosthesis. 13. Patient has participated in, or is planned to participate in, any investigational drug or device study within the past or next 2 months. 14. Patient who has more than 1μCi of any injected or implanted radioactive material within his body.