Study of 68Ga-HBED-PSMA PET/CT and Conventional Imaging in Occult Biological Relapse Prostate Cancer

Inclusion Criteria:

1. Age above 18 years
2. Diagnosis of histologically proven prostate cancer.
3. Patient having benefited from previous curative treatment (prostatectomy, radiotherapy, ultrasound, cryotherapy ...), with a significant decrease in the plasma concentration of PSA at the end of treatment (= indisputable PSA)
4. Biologic recurrence documented by abnormal results in 2 assays of plasma PSA concentration in the same laboratory.
5. Value of the plasma concentration of the last PSA assay during the 4 months preceding D0: 0.05 ng / mL ≤ PSA \<1.6 ng / mL
6. Conventional imaging assessment already carried out, including at least one optimized skeleton scintigraphy with thoracoabdominopelvic TEMP / CT (or 18F-Choline TEP) and pelvic MRI (or abdominopelvic CT if contraindicated MRI) less than 6 weeks old. All of these tests must have been interpreted as "negative" or "questionable" (without "suggestive" or "suspect" aspects of malignancy) written by the imaging specialist.
7. Karnofsky ≥ 70 or ECOG 0-1
8. Life expectancy of at least 6 months
9. The patient has given his written consent.
10. Patient affiliated to a social security scheme

Exclusion Criteria:

1. Another progressive cancerous condition, except for basal cell cancers.
2. Acute inflammatory condition,
3. Implementation of treatment (eg chemotherapy) or change of treatment (eg hormone therapy) since skeletal scintigraphy, abdominopelvic MRI or the last serum PSA test.
4. Radiotherapy, chemotherapy or other anti-tumor treatment during the 6 weeks preceding PET,
5. Agitation; impossibility to hold motionless for at least 1 hour, or known claustrophobia
6. Poor predictable compliance or inability to undergo medical follow-up of the test for geographical, social or psychological reasons,
7. Intellectual inability to sign informed consent
8. Persons deprived of liberty or guardianship (including trusteeship),