• Interest of hybrid PET-MRI/[68Ga]PSMA imaging compared to PET-Choline for the metastasis detection during the initial assessment of first recurrence after radiotherapy. [ Time Frame: Screening period. ]
  Interest of hybrid PET-MRI/[68Ga]PSMA imaging compared to PET-Choline for the metastasis detection during the initial assessment for first recurrence after radiotherapy will be evaluated by the proportion of patient who could not be treated by Focal-HIFU because of evidence of metastasis after the first PET-MRI/[68Ga]PSMA (screening failure rate).
• Interest of hybrid PET-MRI/[68Ga]PSMA imaging compared to standard multiparametric MRI performed at the initial assessment AND 6 month after Focal-HIFU. [ Time Frame: 6 months after focal HIFU therapy ]
  Interest of hybrid PET-MRI/[68Ga]PSMA imaging compared to standard multiparametric MRI will be evaluated by tumor volume comparison between both imaging method at the initial assessment AND 6 months after Focal-HIFU
• Biological recurrence [ Time Frame: 3 months and 6 months after focal HIFU therapy ]
  Biological recurrence will be evaluated by the proportion of biological recurrence, defined by a PSA nadir increase of more than 2 ng/mL at 3 and 6 months after Focal-HIFU.
• Local control of tumor recurrence 6 months after Focal-HIFU guided by PET-MRI/[68Ga]PSMA imaging. [ Time Frame: 6 months after focal HIFU therapy ]
  Local control of tumor recurrence 6 months after Focal-HIFU guided by PET-MRI/[68Ga]PSMA imaging will be evaluated by a second imaging assessment by PET-MRI/[68Ga]PSMA à 6 months after Focal-HIFU. In case of PSMA fixation on this imaging assessment, prostate biopsies will be performed.
• Proportion of positives prostate biopsies [ Time Frame: 3 months and 6 months after focal HIFU therapy ]
  Carcinologic evolution will be evaluated according to usual assessment performed for biological recurrence with proportion of positives prostate biopsies in the treated lobe and/or in the non-treated lobe.
• Gleason score [ Time Frame: 3 months and 6 months after focal HIFU therapy ]
  Carcinologic evolution will be evaluated according to usual assessment performed for biological recurrence with evolution of the Gleason score (4+3 = 7 or ≥ 8).
• Extracapsular extension of prostate cancer. [ Time Frame: 3 months and 6 months after focal HIFU therapy ]
  Carcinologic evolution will be evaluated according to usual assessment performed for biological recurrence with extracapsular extension of prostate cancer.
• Metastatic free survival [ Time Frame: Over the 6 months after focal HIFU therapy ]
  The metastatic free survival will be measured from the inclusion date to the date of first metastasis confirmation
• QLQC30 score (Quality of life questionnaire) [ Time Frame: 3 months and 6 months after focal HIFU therapy ]
  Quality of life will be assessed using the QLQC30 (Quality of Life questionnaire) questionnaire. It is a specific questionnaire to determine the quality of life a patient with cancer. It is composed of 30 questions with 4 potential answers going from: not at all, a little, enough or a lot, within 28 questions and with a visual scale going from 1 to 7 (7 being excellent and 1 being very bad) for the last 2 questions. The raw score is established by adding the score of each question and a linear transformation range it from 0 to 100. The higher the score, the better the quality of life.
• EPIC-26 score (Urinary function questionnaire) [ Time Frame: 3 months and 6 months after focal HIFU therapy ]
  Urinary function will be assessed using the EPIC-26 (The Expanded Prostate Cancer Index Composite) questionnaire. The EPIC-26 is a self-reported scale health-related quality of life questionnaire for prostate cancer patients. It is composed of 26 items in 4 different domains: urinary incontinence, urinary irritation/obstruction, bowel, sexual, and vitality/hormonal. Response options for each EPIC item form a Likert scale, and multi-item scale scores are transformed linearly to a 0-100 scale. Each items as a standardized value from 0 to 100. Then the average of the standardized value is determined in each domain to crate the summary score. The higher the score, the better the quality of life.
• IPSS score (Urinary function questionnaire) [ Time Frame: 3 months and 6 months after focal HIFU therapy ]
  Urinary function will be assessed using the IPSS (International Prostate Score Symptom) questionnaire. The IPSS questionnaire is based on the answers to seven questions concerning urinary symptoms and one question concerning quality of life. Each question concerning urinary symptoms allows the patient to choose one out of six answers indicating increasing severity of the particular symptom. The answers are assigned points from 0 to 5. The total score can therefore range from 0 to 35. The score is then categorized as follow: Mild (symptoms score less than or equal to 7), Moderate (symptom score range 8-19), Severe (symptom score range 20-35). The higher the score, the worse the symptoms.
• IIEF-5 score (Sexual function questionnaire) [ Time Frame: 3 months and 6 months after focal HIFU therapy ]
  Sexual function will be assessed using will be assessed using the IIEF-5 (The International Index of Erectile Function) questionnaire.The IIEF-5 Questionnaire is composed of 5 items with 5 possible answers rating from 1 to 5 (very low, low, moderate, high, very high). The score is the sum of the ordinal responses to the 56 items. It is then categorized as follow: 22-25: No erectile dysfunction, 17-21: Mild erectile dysfunction, 12-16: Mild to moderate erectile dysfunction, 8-11: Moderate erectile dysfunction, 5-7: Severe erectile dysfunction. The higher the score, the better the sexual function.
• Adverse event evaluation [ Time Frame: During 6 months of follow-up after focal HIFU therapy ]
  Adverse events assessment between patient inclusion to the last study visit at 6 months (+/- 30 days) after Focal-HIFU treatment
• Ancillary study: Measure of anti-tumoral immunity induction [ Time Frame: Over the 6 months ]
  The consequences of HIFU treatment over immune anti-tumoral induction will be estimated by the description of Programmed death-ligand 1/ligand 2 (PDL1/L2) overexpression on immune cells and overexpression of Programmed cell death 1 (PD-1) on T lymphocytes (T-cells).
• Circulating Tumor Cells (CTC) number [ Time Frame: Over the 6 months ]
  The consequences of HIFU treatment over Messenger RNA (mRNA) will be estimated by measure of CTC number reduction (ancillary study).
• ncRNA (non-coding RNA) PCA3 (Prostate cancer gene 3) level [ Time Frame: Over the 6 months ]
  The consequences of HIFU treatment over PCA3 will be estimated by measure of ncRNA PCA3 level reduction (ancillary study).

• Interest of hybrid PET-MRI/[68Ga]PSMA imaging compared to PET-Choline for the metastasis detection during the initial assessment of first recurrence after radiotherapy. [ Time Frame: Screening period. ]
  Interest of hybrid PET-MRI/[68Ga]PSMA imaging compared to PET-Choline for the metastasis detection during the initial assessment for first recurrence after radiotherapy will be evaluated by the proportion of patient who could not be treated by Focal-HIFU because of evidence of metastasis after the first PET-MRI/[68Ga]PSMA (screening failure rate).
• Interest of hybrid PET-MRI/[68Ga]PSMA imaging compared to standard multiparametric MRI performed at the initial assessment AND 6 month after Focal-HIFU. [ Time Frame: 6 months after focal HIFU therapy ]
  Interest of hybrid PET-MRI/[68Ga]PSMA imaging compared to standard multiparametric MRI will be evaluated by tumor volume comparison between both imaging method at the initial assessment AND 6 months after Focal-HIFU
• Impact of PET-MRI/[68Ga]PSMA guidance of Focal-HIFU treatment on biological recurrence at 3 and 6 months after Focal-HIFU treatment. [ Time Frame: 3 months and 6 months after focal HIFU therapy ]
  Impact of PET-MRI/[68Ga]PSMA guidance of Focal-HIFU on biological recurrence will be evaluated by the proportion of biological recurrence, defined by a PSA nadir increase of more than 2 ng/mL at 3 and 6 months after Focal-HIFU.
• Local control of tumor recurrence 6 months after Focal-HIFU guided by PET-MRI/[68Ga]PSMA imaging. [ Time Frame: 6 months after focal HIFU therapy ]
  Local control of tumor recurrence 6 months after Focal-HIFU guided by PET-MRI/[68Ga]PSMA imaging will be evaluated by a second imaging assessment by PET-MRI/[68Ga]PSMA à 6 months after Focal-HIFU. In case of PSMA fixation on this imaging assessment, prostate biopsies will be performed.
• Proportion of positives prostate biopsies [ Time Frame: 3 months and 6 months after focal HIFU therapy ]
  Impact of PET-MRI/[68Ga]PSMA guidance of Focal-HIFU treatment on carcinologic evolution will be evaluated according to usual assessment performed for biological recurrence with proportion of positives prostate biopsies in the treated lobe and/or in the non-treated lobe.
• Gleason score [ Time Frame: 3 months and 6 months after focal HIFU therapy ]
  Impact of PET-MRI/[68Ga]PSMA guidance of Focal-HIFU treatment on carcinologic evolution will be evaluated according to usual assessment performed for biological recurrence with evolution of the Gleason score (4+3 = 7 or ≥ 8).
• Extracapsular extension of prostate cancer. [ Time Frame: 3 months and 6 months after focal HIFU therapy ]
  Impact of PET-MRI/[68Ga]PSMA guidance of Focal-HIFU treatment on carcinologic evolution will be evaluated according to usual assessment performed for biological recurrence with extracapsular extension of prostate cancer.
• Metastatic free survival [ Time Frame: Over the 6 months after focal HIFU therapy ]
  The metastatic free survival will be measured from the inclusion date to the date of first metastasis confirmation
• QLQC30 score (Quality of life questionnaire) [ Time Frame: 3 months and 6 months after focal HIFU therapy ]
  Impact of PET-MRI/[68Ga]PSMA guidance of Focal-HIFU treatment on quality of life will be assessed using the QLQC30 (Quality of Life questionnaire) questionnaire. It is a specific questionnaire to determine the quality of life a patient with cancer. It is composed of 30 questions with 4 potential answers going from: not at all, a little, enough or a lot, within 28 questions and with a visual scale going from 1 to 7 (7 being excellent and 1 being very bad) for the last 2 questions. The raw score is established by adding the score of each question and a linear transformation range it from 0 to 100. The higher the score, the better the quality of life.
• EPIC-26 score (Urinary function questionnaire) [ Time Frame: 3 months and 6 months after focal HIFU therapy ]
  Impact of PET-MRI/[68Ga]PSMA guidance of Focal-HIFU treatment on urinary function will be assessed using the EPIC-26 (The Expanded Prostate Cancer Index Composite) questionnaire. The EPIC-26 is a self-reported scale health-related quality of life questionnaire for prostate cancer patients. It is composed of 26 items in 4 different domains: urinary incontinence, urinary irritation/obstruction, bowel, sexual, and vitality/hormonal. Response options for each EPIC item form a Likert scale, and multi-item scale scores are transformed linearly to a 0-100 scale. Each items as a standardized value from 0 to 100. Then the average of the standardized value is determined in each domain to crate the summary score. The higher the score, the better the quality of life.
• IPSS score (Urinary function questionnaire) [ Time Frame: 3 months and 6 months after focal HIFU therapy ]
  Impact of PET-MRI/[68Ga]PSMA guidance of Focal-HIFU treatment on urinary function will be assessed using the IPSS (International Prostate Score Symptom) questionnaire. The IPSS questionnaire is based on the answers to seven questions concerning urinary symptoms and one question concerning quality of life. Each question concerning urinary symptoms allows the patient to choose one out of six answers indicating increasing severity of the particular symptom. The answers are assigned points from 0 to 5. The total score can therefore range from 0 to 35. The score is then categorized as follow: Mild (symptoms score less than or equal to 7), Moderate (symptom score range 8-19), Severe (symptom score range 20-35). The higher the score, the worse the symptoms.
• IIEF-5 score (Sexual function questionnaire) [ Time Frame: 3 months and 6 months after focal HIFU therapy ]
  Impact of PET-MRI/[68Ga]PSMA guidance of Focal-HIFU treatment on sexual function will be assessed using will be assessed using the IIEF-5 (The International Index of Erectile Function) questionnaire.The IIEF-5 Questionnaire is composed of 5 items with 5 possible answers rating from 1 to 5 (very low, low, moderate, high, very high). The score is the sum of the ordinal responses to the 56 items. It is then categorized as follow: 22-25: No erectile dysfunction, 17-21: Mild erectile dysfunction, 12-16: Mild to moderate erectile dysfunction, 8-11: Moderate erectile dysfunction, 5-7: Severe erectile dysfunction. The higher the score, the better the sexual function.
• Adverse event evaluation [ Time Frame: During 6 months of follow-up after focal HIFU therapy ]
  Adverse events assessment between patient inclusion to the last study visit at 6 months (+/- 30 days) after Focal-HIFU treatment
• Ancillary study: Measure of anti-tumoral immunity induction [ Time Frame: Over the 6 months ]
  The consequences of HIFU treatment over immune anti-tumoral induction will be estimated by the description of Programmed death-ligand 1/ligand 2 (PDL1/L2) overexpression on immune cells and overexpression of Programmed cell death 1 (PD-1) on T lymphocytes (T-cells).
• Circulating Tumor Cells (CTC) number [ Time Frame: Over the 6 months ]
  The consequences of HIFU treatment over Messenger RNA (mRNA) will be estimated by measure of CTC number reduction (ancillary study).
• ncRNA (non-coding RNA) PCA3 (Prostate cancer gene 3) level [ Time Frame: Over the 6 months ]
  The consequences of HIFU treatment over PCA3 will be estimated by measure of ncRNA PCA3 level reduction (ancillary study).

A significant proportion of patients with localized prostate cancer, and treated for curative intent by radiotherapy, have a local recurrence. Among these patients with local recurrence, few receive curative remedial treatment but most of them are treated with palliative hormonal therapy without any chance of long-term recovery.

The use of Focused Ultrasound (HIFU) in focal treatment (only on recurrence) is an effective and not very morbid option, especially compared to surgery. The quality of this treatment is conditioned by both an early diagnosis of recurrence, a precise localization of recurrence in the prostate and a rigorous extension assessment for the detection of occult metastases.

Innovations in medical imaging have led to the development of a new generation of "hybrid" machines that combine PET (Positron Emission Tomodensitometry) and MRI (Magnetic Resonance Imaging) technology. Associated with the use of 68Gallium-labeled PSMA (Prostate-Specific Membrane Antigen), a new tracer specific for prostate cancer, the investigators believe that this PET-MRI imaging technique can:

1. To identify at an early stage the metastatic patients and to allow a more adapted therapeutic management.
2. A better evaluation of the limits of local recurrence and therefore a more precise definition than with MRI alone of the tumor zone to be destroyed.

Finally, the investigators believe that the PET-MRI / 68Ga-PSMA exam, used for the selection of patients eligible for focal HIFU treatment and used for the treatment itself, should allow obtaining an optimal control of the cancer recurrence with the least possible side effects.

Inclusion Criteria:

1. 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 G8 score > 14.
2. Biological recurrence after prostate radiotherapy confirmed with de Phoenix criteria (nadir + 2 ng/mL).
3. No prior or present evidence of lymph node metastasis, soft tissue metastasis or bone metastasis, assessed by the current radiographic exam (PET-Choline) AND the PET-MRI/68Ga-PSMA before Focal-HIFU.

4. Local prostate cancer recurrence confirmed by:

   • A multiparametric MRI showing a single tumor in the prostate gland at most 3 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 biopsies.
   • Index tumor confirmed by the PET-MRI/68Ga-PSMA.
5. PSA ≤ 10ng/ml.
6. 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.
7. Patient affiliated with health insurance or beneficiary of an equivalent plan.

Exclusion Criteria:

1. Contraindications to Focal-HIFU treatment.
2. Patient with a medical contraindication to Sonovue® injection.
3. Patient with a medical contraindication to MRI.
4. History of uncontrolled cancer and / or treated for less than 5 years (with the exception of basal cell skin cancer).
5. History of sclerosis of the bladder neck or urethral stenosis.
6. Patient at risk of bleeding according to medical advice. Patient with anticoagulants therapy must receive a treatment relay.
7. Patients with unstable neurological pathology.
8. 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.
9. Legal person protected by law.
10. Patient not able to understand the objectives of the study or refusing to comply with postoperative instructions.