Intraprostatic MAXimal Simultaneous Boost

Inclusion Criteria: 1. Patients must have histologically proven adenocarcinoma of the prostate. 2. Registration must occur within 26 weeks of biopsy. 3. History and physical examination (including digital rectal examination (DRE)) within 8 weeks prior to registration. 4. Patients must have intermediate risk prostate cancer, as defined by: * PSA ≤ 20 ng/ml, * Gleason ≤ 7, * Stage ≤ T2c, and * Do not meet criteria for low-risk prostate cancer (Low-risk = All of: PSA ≤ 10 + Gleason ≤ 6 + stage ≤ T2b) 5. Patients must have the following blood tests within two weeks of registration: * Prostate specific antigen (PSA), testosterone (TTT), complete blood count (CBC), electrolytes, creatinine. * Patients with values for one or more of these tests (not including PSA) that fall outside the normal range will need to be reviewed by the oncologist to determine their eligibility for this study. 6. Patients must have an estimated life expectancy of at least 10 years. 7. Patients must have an Eastern Cooperative Oncology Group (ECOG) performance status of 0 - 2. 8. Patients must have no contraindications to high dose pelvic irradiation. 9. Patients must not have received prior radiation therapy to the pelvis. 10. Patients must have no history of inflammatory bowel disease. 11. Patients must not have received prior hormonal therapy or chemotherapy. 12. Patients must not have any hormonal therapy planned as part of the therapeutic intervention. 13. Patients must have no contraindication to MRI scanning. 14. Patients should not have an artificial hip 15. Patients should not have a body mass index (BMI) of \> 32. Note: BMI = weight in kg ÷ (height in metres)2 Exclusion Criteria: 1\. Subjects that do not meet inclusion criteria.