 Our goal is to develop a non-invasive PET-CT imaging method based on binding of a molecule 18F-fallypride for tracking beta-cell loss during the progression of T1DM. In preliminary studies we demonstrated specific binding of 18F-fallypride to D2 receptors in rat pancreatic sections and we demonstrated that the loss of pancreatic beta cells in streptozotocin-treated rats was associated with a corresponding decrease in 18F-fallypride binding to pancreatic sections. A preliminary 18F-fallypride PET-CT study done by a collaborator in Ohio on a healthy volunteer, revealed 18F-fallypride-uptake by the pancreas that was distinguishable from surrounding tissues. Aim-1 of our project will measure the variability of 18F-fallypride PET-scanning of the pancreas in six healthy volunteers scanned twice with an interval of 4-6 weeks. In Aim-2 of our project, we will compare fallypride PET-CT scans of 12 patients with long-standing T1DM nearly all beta cells destroyed with 12 age- and sex-matched healthy volunteers. If we are able to distinguish between the two groups, we will in future a optimize the method so as to be able to detect a 20-30 loss of beta cells, and b perform PET-CT studies in new-onset T1DM patients and in at-risk first degree relatives of T1DM patients. 