PSMA-PET Guided Radiotherapy

Inclusion Criteria: 1. Enrolled in PERA (CHUM CER 17.0.32) and consented to contact for investigational trials. 2. Histological diagnosis of prostate cancer planned for curative-intent radiotherapy. 3. ECOG 0-1 4. Charlson Cormobidity Index ≤ 4 5. High-risk of distant metastases as defined by any of: 1. Oligometastases (≤5) (regional or distant) identified on conventional staging, with ≤ 3 metastasis in any non-bone organ. For a spine metastasis, direct involvement of adjacent spinal segments would still be considered as "one" tumour. For nodal metastases, more than one involved lymph node in the same ipsilateral nodal region/chain would still count as "one" tumour. Defined nodal regions for this protocol include inguinal, external iliac, internal iliac, common iliac, retroperitoneal, hilar/mediastinal, anterior cervical, posterior cervical, and axillary. Metastases in all other organs that are within 1cm of each other will be considered as "one" tumour. 2. Subjects with newly diagnosed high-risk (NCCN) localized prostate cancer and CAPRA score 6-10. 3. Subjects with a prior history of treated prostate cancer (RP or RT), and biochemical failure (Phoenix-RT or\>0.2ng/ml-RP) 6. Standard staging (bone scan, CT pelvis) within 12 weeks of consent. Exclusion Criteria: 1. Prior androgen deprivation therapy terminated \< 12 months prior to enrollment. 2. Prior or planned PET scan.