RT Journal Article SR Electronic T1 Effect of Carbidopa on 18F-FDOPA Uptake in Insulinoma: From Cell Culture to Small-Animal PET Imaging JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 36 OP 41 DO 10.2967/jnumed.116.180588 VO 58 IS 1 A1 Julien Detour A1 Alice Pierre A1 Fréderic Boisson A1 Guillaume Kreutter A1 Thomas Lavaux A1 Izzie Jacques Namer A1 Laurence Kessler A1 David Brasse A1 Patrice Marchand A1 Alessio Imperiale YR 2017 UL http://jnm.snmjournals.org/content/58/1/36.abstract AB Patient premedication with carbidopa seems to improve the accuracy of 6-18F-fluoro-3,4-dihydroxy-l-phenylalanine (18F-FDOPA) PET for insulinoma diagnosis. However, the risk of PET false-negative results in the presence of carbidopa is a concern. Consequently, we aimed to evaluate the effect of carbidopa on 18F-FDOPA uptake in insulinoma β-cells and an insulinoma xenograft model in mice. Methods: 18F-FDOPA in vitro accumulation was assessed in the murine β-cell line RIN-m5F. In vivo small-animal PET experiments were performed on tumor-bearing nude mice after subcutaneous injection of RIN-m5F cells. Experiments were conducted with and without carbidopa pretreatment. Results: Incubation of RIN-m5F cells with 80 μM carbidopa did not significantly affect the cellular accumulation of 18F-FDOPA. Tumor xenografts were clearly detectable by small-animal PET in all cases. Insulinoma xenografts in carbidopa-treated mice showed significantly higher 18F-FDOPA uptake than those in nontreated mice. Regardless of carbidopa premedication, the xenografts were characterized by an early increase in 18F-FDOPA uptake and then a progressive reduction over time. Conclusion: Carbidopa did not influence in vitro 18F-FDOPA accumulation in RIN-m5F cells but improved insulinoma imaging in vivo. Our findings increase current knowledge about the 18F-FDOPA uptake profile of RIN-m5F cells and a related xenograft model. To our knowledge, the present work represents the first preclinical research specifically focused on insulinomas, with potential translational implications.