Comparison of [68Ga]Ga-HBED-CC-PEG6-Exendin-4 and [68Ga]Ga-HBED-CC-Exendin-4 PET/CT for Insulinoma Localization

This clinical research evaluates a new PET/CT imaging agent, \[68Ga\]Ga-HBED-CC-PEG6-exendin-4, for localizing insulinoma, a rare pancreatic tumor that causes severe low blood sugar. Insulinomas are often small and hard to detect with regular CT, ultrasound or standard PET scans. This new tracer targets GLP1R, a protein highly expressed on insulinoma cells, with polyethylene glycol (PEG6) modification to improve tumor uptake and image contrast compared with the earlier similar agent \[68Ga\]Ga-HBED-CC-exendin-4. The investigators plan to enroll 20 adult patients suspected of or confirmed to have insulinoma. All participants will receive two free PET/CT scans within one week: one with the new PEG6-modified tracer and one with the original tracer. The first 3 participants will also get dynamic PET scanning to analyze drug distribution and radiation dose in the human body. Within one month after imaging, patients will undergo surgery or biopsy to get pathological results, which serve as the gold standard to calculate and compare the diagnostic accuracy of the two tracers. All imaging procedures follow standard clinical protocols with safe, low radiation doses within national diagnostic limits. Minor possible risks include slight pain or mild allergic reaction at the injection site; rare side effects related to exendin-4 may occur at a rate below 5%, and the research team has full emergency management measures ready. Participants can withdraw from the study at any time without penalty. All scan fees are covered by the research project, and each subject will receive a formal imaging report for clinical reference. The findings of this trial will help develop a more accurate imaging tool to precisely locate insulinoma and guide surgical treatment.