Critères d'inclusion : •Patient having been clearly informed of the study and having accepted, with sufficient reflection time, to participate by signing the informed consent form of the study.
•Age between 50 and 80 years with a life expectancy of more than 5 years. Patients between the ages of 75 and 80 will need to have a lower G8 score.
•Initial diagnosis of localized prostate cancer (T1 or T2a) with the following characteristics:
◦A multiparametric MRI showing a single invasive tumor focus at most two contiguous sextants confirmed by biopsies (index tumor). Patients with multiple suspected MRI foci may be included if only one of these foci is confirmed by targeted biopsies.
◦The tumor volume on MRI should be> 0.5 cc, ie a tumor ≥10 mm in its longest dimension.
◦A maximum tumor length> 3 mm or at least 3 positive biopsies on all biopsies performed (12 randomized biopsies and 2 biopsies per MRI target guided by fusion software).
◦Gleason 6 score (risk group 1 of the D'Amico classification).
◦Tumor positioned so that a safety distance of at least 9mm can be defined during HIFU-F treatment in prostate tissue around the target.
•PSA ≤ 10ng / ml.
•Patient affiliated with health insurance or beneficiary of an equivalent plan.
Critères de non-inclusion : •Contraindications to treatment with HIFU-F:
◦Tumor not accessible (impossibility to apply a safety margin of 9 mm around the MRI target).
◦Multiple intra prostatic calcifications inducing, on ultrasound, a shadow cone in the prostate preventing the penetration of ultrasound and thus the realization of the treatment.
◦History of pelvic irradiation
◦Presence of an implant (stent, catheter) located less than 1 cm from the treatment area.
◦Fistula of the urinary tract or rectum.
◦Anal or rectal fibrosis, anal or rectal stenosis or other abnormalities making it difficult to insert the Focal One® probe.
◦Anatomical abnormality of the rectum or rectal mucosa.
◦Patient with artificial sphincter, penile prosthesis or intra prostatic implant, eg stent.
◦History of intestinal inflammatory pathology.
◦Uro-genital infection in progress (the infection to be treated before HIFU treatment).
◦Anterior surgery at the level of the anus or rectum making the introduction of the probe impossible.
◦Allergy to latex.
◦Thickness of the rectal wall> 10mm.
•Patient undergoing treatment for benign prostatic hyperplasia (BPH) with IPSS> 25.
•Patient with a medical contraindication to Sonovue® injection.
•Patient with a medical contraindication on MRI.
•Patient already treated for prostate cancer (hormone therapy, radiotherapy, surgery).
•History of uncontrolled cancer and / or treated for less than 5 years (with the exception of basal cell skin cancer).
•History of sclerosis of the bladder neck or urethral stenosis.
•Patient at risk of bleeding according to medical advice.
•Patients with unstable neurological pathology.
•Patient who has been treated for a therapeutic trial within 30 days of enrollment or who wishes to participate in an ongoing study that may interfere with this study.
•Legal person protected by law.
•Patient not able to understand the objectives of the study or refusing to comply with postoperative instructions.