PT - JOURNAL ARTICLE AU - Adriana Garcia AU - Mohammad Reza Mirbolooki AU - Cristian Constantinescu AU - Min-Liang Pan AU - Evegueni Sevrioukov AU - Norah Milne AU - Ping H. Wang AU - Jonathan Lakey AU - K. George Chandy AU - Jogeshwar Mukherjee TI - <sup>18</sup>F-Fallypride PET of Pancreatic Islets: In Vitro and In Vivo Rodent Studies AID - 10.2967/jnumed.111.088583 DP - 2011 Jul 01 TA - Journal of Nuclear Medicine PG - 1125--1132 VI - 52 IP - 7 4099 - http://jnm.snmjournals.org/content/52/7/1125.short 4100 - http://jnm.snmjournals.org/content/52/7/1125.full SO - J Nucl Med2011 Jul 01; 52 AB - Islet cell loss in the pancreas results in diabetes. A noninvasive method that measures islet cell loss and also tracks the fate of transplanted islets would facilitate the development of novel therapeutics and improve the management of diabetes. We describe a novel dopamine D2/D3 receptor (D2/D3R)–based PET method to study islet cells in the rat pancreas and in islet cell transplantation. Methods: 18F-fallypride binding to isolated rat islets and pancreas was evaluated in the absence and presence of the D2/D3R inhibitor haloperidol. After intravenous 18F-fallypride (28–37 MBq) administration, normal rats and rats pretreated with haloperidol were imaged in a PET/CT scanner and subsequently studied ex vivo for 18F-fallypride localization in the pancreas. A streptozotocin-treated diabetic rat model was used to study localization of 18F-fallypride in the pancreas, in vitro and ex vivo. Rat islet cells were transplanted into the spleen and visualized using 18F-fallypride PET. Results: 18F-fallypride bound to isolated islet cells and pancreatic sections with an endocrine or exocrine selectivity of approximately 4; selectivity was reduced by haloperidol, suggesting that binding was D2/D3R-specific. Chemical destruction of islets by streptozotocin decreased 18F-fallypride binding in pancreas by greater than 50%, paralleling the decrease in insulin immunostaining. Uptake of 18F-fallypride in the pancreas was confirmed by radiochromatography and was 0.05% injected dose/cm3 as measured by PET/CT. The ratio of 18F-fallypride uptake in the pancreas to reference tissue (erector spinae muscle) was 5.5. Rat islets transplanted into the spleen were visualized in vivo by 18F-fallypride and confirmed by immunostaining. The ratio of spleen-transplanted islets to erector spinae muscle was greater than 5, compared with a ratio of 2.8 in untransplanted rats. Conclusion: These studies demonstrate the potential utility of 18F-fallypride as a PET agent for islet cells.