In vivo positron emission tomography (PET) imaging with an α_vβ₆ 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 [ ¹⁸F]fluorine, peptides are radiolabeled via a prosthetic group approach. We previously developed solution-phase ¹⁸F- "click" radio-labeling and solid-phase radiolabeling using 4-[ ¹⁸F]fiuorobenzoic and 2-[¹⁸F]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.