Dynamic 68Ga-PSMA and 18F-FDG PET/CT Analysis Prior to 177Lu-PSMA

Prostate cancer is a significant health issue, representing 21.8% of male cancer cases in France with over 449,000 new cases in 2018. It's the cause of 10% of cancer deaths in Europe. The PSMA is a target for mCRPC treatment, with therapies like 177Lu-PSMA-617 delivering radiation to cancer cells. The Vision study showed that 177Lu-PSMA-617, combined with standard care, improved survival rates significantly compared to standard care alone.The French ANSM authorized 177Lu-PSMA-617 for mCRPC under certain conditions. Patients must have histologically confirmed mCRPC, be progressive despite treatment, and have PSMA-positive imaging. Imaging assessments include PSMA PET/CT and 18F-FDG PET/CT to identify FDG-positive and PSMA-negative sites, which are associated with a poorer prognosis. Parametric analysis using dynamic PET could improve lesion characterization, aiding in treatment decisions. This is the focus of the PyPET study. The main objective focuses on a comparative analysis of data from dynamic parametric analysis (metabolic influx rate Ki, volume of distribution Vd) and static analysis (standard at 1 hour) using 18F-FDG and 68Ga-PSMA PET/CT for diagnosing metastases, especially in the liver, lymph nodes, and bones. It aims to assess the effectiveness of these imaging techniques in accurately identifying metastatic sites.