Inclusion Criteria:  prostate adenocarcinoma WHO performance index ≤ 1  Patient presenting one of the following cases:  Low risk: ≤ T2a and Gleason 6 (3 + 3) and PSA <10 ng / ml Intermediate risk: T2b-T2c or Gleason 7 or PSA <15 ng / ml High localized risk: T3a and Gleason ≤7 and PSA <15 ng / ml Disease presenting a risk of lymph node involvement <15% Absence of pelvic or lumbar aortic lymphadenopathy Absence of bone or visceral metastasis IPSS score <15 or ≤ 7 Prostate volume estimated by MRI or ultrasound < 90cc If hormonotherapy, hormone therapy must not have started for more than 60 days before inclusion. Absence of prior pelvic radiotherapy No surgical treatment for prostate cancer  Exclusion Criteria:  Prostate cancer of histology other than adenocarcinoma Contraindication to MRI including, but not limited to, patients with a pacemaker or defibrillator Patient diagnosed N1 during imaging workup or pN1 Serum PSA level ≥ 15 ng / ml IPSS score ≥ 15 or IPSS score> 7 if alpha blocking urological treatment in progress Prostate volume estimated on MRI or ultrasound> 90 cc Involvement of seminal vesicles on MRI History of cancer in the 5 years preceding entry into the trial History of transurethral resection of the prostate less than 6 months compared to the expected date of start of radiotherapy rectal surgery pelvic irradiation Patient treated with antineoplastic or medication which may include Methotrexate Hormone therapy started for more than 60 days at the time of inclusion Severe uncontrolled hypertension Patient followed or treated for severe or unstable angina, or having presented a myocardial infarction in the 6 months preceding the randomization Patient on immunosuppressant Patient with known hypersensitivity to gadoteric acid, meglumine or any drug containing gadolinium