cFLFLF is a FPR-specific peptide. cFLFLF is sequentially conjugated with a bifunctional polyethylene glycol moiety (PEG, 3.4 kD) and a DOTA through a lysine (K) spacer and finally labeled with 64Cu-CuCl2 to form cFLFLFKPEG-64Cu. cFLFLFKPEG-64Cu is a neutrophil-specific PET imaging agent[1].