Evaluation of Sodium Fluoride PET in the Identification of Bone Metastases in Patients Having Undergone a Choline PET for Occult Recurrence of Prostatic Adenocarcinoma

The purpose is to evaluate if sodium fluoride PET in patients having already undergone a choline PET negative for bone extension (non-metastatic status) modifies the status of patients concerning the existence or not of bone metastases. Secondary purposes are: * To evaluate if detection of bone metastasis by sodium fluoride PET, not detected by choline PET, leads to change of treatment * To evaluate inter-technique concordance (choline vs sodium fluoride PET) of results (metastatic status and number of lesions) * To evaluate the inter-judge concordance of interpretation of sodium fluoride PET * To study the discordance of metastatic status of 2 techniques.