Inclusion Criteria:

- Prostate adenocarcinoma proved by histology

- With at least one of this intermediate-risk criterias:

- T2b

- and/or PSA between 10 et 20 ng/ml

- and/or Gleason score = 7

- Prostatic volume ≤ 80 cc

- No adenopathy(lymph node < 1.5 cm on scanner or MRI and/or in lymph node dissection)

- No metastasis (bone scan)

- Age >= 18 ans

- No prior pelvic irradiation

- No prior anticancer treatment (prostatectomy, chemotherapy, hormonotherapy > 3
months)

- Performance status (ECOG) < 1

- No contraindication of fiducials implantation, hemostasis disorders must be treated
before the implantation

- Life expectancy >= 10 weeks

- Patient affiliated to health insurance

- Informed consent signed by the patient

Exclusion Criteria:

- Cancer no histologically proved

- Unfavorable-risk(T2c and/or PSA > 20 ng/ml and/or Gleason > 7)

- Favorable-risk(T1c T2a and PSA < 10 ng/ml and Gleason < 7)

- T3 and T4

- History of cancer uncontrolled and/or treated since less of 5 years (except basal
cell carcinoma of the skin)

- Contraindication to MRI

- IPSS score > 10

- Recurrent or metastatic disease

- Allergy to gold

- Patient already included in another therapeutic trial with an experimental molecule

- Unable for medical follow-up (geographic, social or mental reasons)