The present invention provides novel fluoroalkyl tetrabenazine carbinol compounds having structure I wherein R1 is a C1-C10 fluorinated aliphatic radical; R2 is a C1-C10 aliphatic radical; R3 is hydrogen or a C1-C10 aliphatic radical; R4 is hydrogen or a C1-C10 aliphatic radical; and R5 is hydrogen, a C1-C10 aliphatic radical, a C2-C10 cycloaliphatic radical, or a C2-C20 aromatic radical. In a particular embodiment, —OR5 is an ester moiety. The fluoroalkyl tetrabenazine carbinol compounds are provided in both racemic and enantiomerically enriched forms and may comprise either or both of fluorine-18 and fluorine 19. The fluoroalkyl tetrabenazine carbinol compounds are shown to possess high affinity for VMAT-2, a biomarker implicated in human diabetes. The fluoroalkyl tetrabenazine carbinol compounds comprising a fluorine-18 group are useful as PET imaging agents targeting the VMAT-2 biomarker. The non-radiolabled fluoroalkyl tetrabenazine carbinol compounds are useful as probes for the discovery of PET imaging agents.