This is the preclinical study investigating the utility of [18F]FB(ePEG12)12-exendin-4, a novel PEGylated exendin-4-based probe, in PET/CT imaging for detecting insulinoma using both INS-1 xenograft mouse models and Pdx1-Cre;Trp53R172H;Rbf/f mice, a novel multiple panNEN mouse model, with developed endogenous insulinoma and glucagonoma. Here, PDX1 is linked to pancreatic insulinoma.