1. Academic Department of Nuclear Medicine, School of Medicine, AHEPA University Hospital, 54636 Thessaloniki, Greece
2. Athens Medical Centre, 65403 Athens, Greece
3. Center for Diabetes and Endocrine Research, College of Medicine and Life Sciences, University of Toledo, Toledo, OH 43606, USA
4. Division of Diabetes, Endocrinology and Gastroenterology, School of Medical Sciences, University of Manchester, Manchester M13 9PL, UK
5. Diabetes Unit, Division of Endocrinology, 1st Department of Internal Medicine, AHEPA University Hospital, 54636 Thessaloniki, Greece