FAP PET/CT or PET/MR Production in the Diagnosis, Staging, and Efficacy Assessment of Malignant Tumors Application

Fibroblast activation protein (FAP), a type II transmembrane serine protease with dipeptidyl peptidase and endopeptidase activities. FAP is a specific surface marker for activated fibroblasts in the mesenchyme of tumors, which account for 90% of the stroma of epithelial neoplasms. FAP inhibitors (FAPIs) can specifically target and bind to FAP. These inhibitors that are radiolabeled with gallium 68 (68Ga-FAPIs) can be probes for visualization of the FAP tumor stroma. Previous studies have demonstrated that 68Ga-FAPI-04 is not dependent on blood glucose levels, has an equal or better tumor-to-background ratio, and clearly visualizes primary tumors and their metastatic foci. In addition, previous studies on 68Ga-FAPI-04 have focused on PET/CT and the efficacy of PET/MR with FAPI for postoperative evaluation of GI tumors remains to be clarified.