Diabetes mellitus is a rising epidemic throughout the world and there is currently great interest in quantifying the beta-cell mass (BCM) in vivo non-invasively. In the present experiment, the feasibility of in vivo imaging of the glucagon-like peptide-1 receptor (GLP-1R) in beta-cells was examined, using the positron emission tomography (PET) tracer [68Ga]Ga-DO3A-VS-Cys40-exendin-4 as a marker, in native pancreatic beta-cells of a porcine diabetic animal model and healthy controls. Eight Swedish high-health domestic pigs were randomly assigned to be either controls or made diabetic using streptozotocin (STZ). The experiment proceeded during eight weeks, starting with an acclimatisation period. Once the pigs had been socialised they underwent surgery for the insertion of a jugular vein catheter, allowing induction of diabetes with STZ, intravenous (i.v.) injections and stress-free blood sampling. Development of diabetes was confirmed by clinical examinations, blood glucose values and insulin-staining of pancreatic sections post mortem. The diabetic pigs were insulin treated and responded well.