Abstract
160
Objectives Based on our newly developed reagent 18F-vinyl sulfone (18F-DEG-VS), 18F-DEG-VS-NT has been developed for neurotensin receptor (NTR) targeted imaging. In this work, we investigate whether this thio-reactive synthon demonstrates benefits compared with the well established 18F-FBEM labeling method.
Methods Based on the well established 18F-FBEM and our newly developed 18F-vinyl sulfone reagents, 18F-FBEM-NT and 18F-DEG-VS-NT were synthesized for NTR1 targeted imaging. In vivo PET scans and metabolic stability studies were carried out using nude mice bearing HT29 xenografts.
Results 18F-FBEM-NT and 18F-DEG-VS-NT were obtained in >90% yield based on HPLC integration. Both agents demonstrated good stability in PBS solution (>95% after 4h incubation). However, the metabolic stability study demonstrated that these agents had several metabolites in vivo, which might due to the short half life of neurotensin analog (no degradation was observed for 18F-FBEM-cRGDyC and 18F-DEG-VS-cRGDyC). No obvious bone uptake was observed in imaging study indicating in vivo defluorination is neglectable. Although both tracers demonstrated no significant difference in stability studies, 18F-DEG-VS-NT did have significantly lower abdomen background and higher tumor uptake compared with 18F-FBEM-NT.
Conclusions Compared with 18F-FBEM-NT, 18F-DEG-VS-NT showed better imaging quality and contrast in in vivo imaging experiment.
Research Support This work was supported by the grant from Larry L. Hillblom Foundation (2013-D-015-SUP), Jonas Bros Foundation, Juvenile Diabetes Research Foundation, the American Cancer Society (121991-MRSG-12-034-01-CCE), and the USC Department of Radiology.