These findings suggest that the use of hormonal therapy can affect the expression of PSMA and our hypothesis is that ADT therapy could increase the sensitivity of 68Ga-PSMA PET to detect nodal or distant metastasis in patients with prostate cancer. This prospective study consists in two phases. In phase A, 5 patients with newly diagnosed high risk prostate cancer with PSMA-positive nodal or distant metastasis screened by 68Ga-PSMA-11 PET/MRI, are given androgen deprivation therapy (ADT) with GNRH antagonist. After ADT therapy initiation, 68Ga-PSMA-11 PET/MRI is repeated at 7, 14 and 30 days to determine the highest PSMA expression based on SUVmax measurement.