Purpose: The vesicular monoamine transporter, type 2 (VMAT2) is expressed by insulin producing β cells and was evaluated as a biomarker of β cell mass (BCM) by positron emission tomography (PET) with [(18)F]fluoropropyl-dihydrotetrabenazine ([(18)F]FP-(+)-DTBZ).
Procedures: We evaluated the feasibility of longitudinal pancreatic PET VMAT2 quantification in the pancreas in two studies of healthy controls and patients with type 1 or 2 diabetes. VMAT2 binding potential (BPND) was estimated voxelwise using a reference tissue method in a cross-sectional study, followed by assessment of reproducibility using a test-retest paradigm. Metabolic function was evaluated by stimulated c-peptide measurements.
Results: Pancreatic BPND was significantly decreased in patients with type 1 diabetes relative to controls and the test-retest variability was 9.4%.
Conclusions: Pancreatic VMAT2 content is significantly reduced in long-term diabetes patients relative to controls and repeat scans are sufficiently reproducible to suggest the feasibility clinically VMAT2 measurements in longitudinal studies of new onset diabetes.
Keywords: Beta cell mass; Diabetes; PET; Test-retest; VMAT2; [18F]FP-(+)-DTBZ.