In vivo positron emission tomography (PET) imaging with an αvβ6 specific peptide radiolabeled using 18F-click chemistry:: Evaluation and comparison with the corresponding 4-[18F]fluorobenzoyl- and 2-[18F]fluoropropionyl-peptides

Numerous radiolabeled peptides have been utilized for in vivo imaging of a variety of cell surface receptors. For applications in PET using [F-18]fluorine, peptides are radiolabeled via a prosthetic group approach. We previously developed solution-phase F-18-click radio-labeling and solid-phase radiolabeling using 4-[F-18]fluorobenzoic and 2-[F-18]fluoropropionic acids. Here we compare the three different radiolabeling approaches and report the effects on PET imaging and pharmacokinetics. The prosthetic groups did have an effect; metabolites with significantly different polarities were observed.