PT  - JOURNAL ARTICLE
AU  - Julien Detour
AU  - Alice Pierre
AU  - Fréderic Boisson
AU  - Guillaume Kreutter
AU  - Thomas Lavaux
AU  - Izzie Jacques Namer
AU  - Laurence Kessler
AU  - David Brasse
AU  - Patrice Marchand
AU  - Alessio Imperiale
TI  - Effect of Carbidopa on <sup>18</sup>F-FDOPA Uptake in Insulinoma: From Cell Culture to Small-Animal PET Imaging
AID  - 10.2967/jnumed.116.180588
DP  - 2017 Jan 01
TA  - Journal of Nuclear Medicine
PG  - 36--41
VI  - 58
IP  - 1
4099  - http://jnm.snmjournals.org/content/58/1/36.short
4100  - http://jnm.snmjournals.org/content/58/1/36.full
SO  - J Nucl Med2017 Jan 01; 58
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.