Hydrophilic 18F-labeled trans-5-oxocene (oxoTCO) for efficient construction of PET agents with improved tumor-to-background ratios in neurotensin receptor (NTR) imaging

An 18F-labeled trans-5-oxocene (oxoTCO) that is used to construct a PET probe for neurotensin receptor (NTR) imaging through tetrazine ligation is described here. PET probe construction proceeds with 70% RCY based on 18F-oxoTCO and is completed within seconds. The in vivo behaviour of the oxoTCO based PET probe was compared with those of analogous probes that were prepared from 18F-labeled s-TCO and d-TCO tracers. The hydrophilic 18F-oxoTCO probe showed a significantly higher tumor-to-background ratio while displaying comparable tumor uptake relative to the 18F-dTCO and 18F-sTCO derived probes.