Publication
Glucagon-like peptide-1 receptor imaging for localization of insulinomas
Journal Paper/Review - Nov 1, 2009
Christ Emanuel, Maecke Helmut, Martius Ferdinand, Gloor Beat, Clerici Thomas, Sahli Rahel, Brändle Michael, Forrer Flavio, Wild Damian, Reubi Jean Claude
Units
PubMed
Doi
Citation
Type
Journal
Publication Date
Issn Electronic
Pages
Brief description/objective
CONTEXT: The surgical removal of insulinomas is hampered by difficulties to localize it using conventional radiological procedures. Recently these tumors were shown to exhibit a very high density of glucagon-like peptide-1 receptors (GLP-1R) in vitro that may be used as specific targets for in vivo receptor radiolabeling. OBJECTIVE: The objective of the study was to test the 111In-labeled GLP-1R agonist 111In-DOTA-exendin-4 in localizing insulinomas using single photon emission computed tomography in combination with computed tomography images. DESIGN: This was a prospective open-label investigation. SETTING: The study was conducted at three tertiary referral centers in Switzerland. PATIENTS: Patients included six consecutive patients with proven clinical and biochemical endogenous hyperinsulinemic hypoglycemia. INTERVENTION: (111)In-DOTA-exendin-4 was administered iv at a dose of about 90 MBq (30 microg peptide) over 5 min. Whole-body planar images of the abdomen were performed at 20 min, 4 h, 23 h, 96 h, and up to 168 h after injection. After surgical removal of the insulinomas, GLP-1R expression was assessed in the tumor tissue in vitro by GLP-1R autoradiography. MAIN OUTCOME MEASURE: The detection rate of insulinomas was measured. Results: In all six cases, the GLP-1R scans successfully detected the insulinomas identified using conventional methods in four cases. By using a gamma-probe intraoperatively, GLP-1R detection permitted a successful surgical removal of the tumors in all patients, diagnosed histopathologically as five pancreatic and one extrapancreatic insulinomas. In vitro GLP-1R autoradiography showed a high density of GLP-1R in all tested insulinomas. CONCLUSION: In vivo GLP-1R imaging is an innovative, noninvasive diagnostic approach that successfully localizes small insulinomas pre- and intraoperatively and that may in the future affect the strategy of insulinoma localization.