Eriksson O, et al. - Keeping the objective in mind, islet-to-exocrine pancreas ratio as well as the exocrine Glucagon-like peptide-1 receptor density is the main determinants of the species variability in pancreatic uptake. Therefore, the islet-to-exocrine pancreas ratio in human is an important factor for evaluating the potential of Glucagon-like peptide-1 receptor as an imaging biomarker for pancreatic beta cells.