The present invention relates to a peptide labelled with fluorine-18 for the specific recognition of lipid vectors. The peptide of the invention comprises the following peptide sequence (PI): (I) J1-J2-J3-J4-J5-J6-Z7-U8-J9-J10-U11-Arg-J13-J14- U15-Lys-Gly-X18-Gly-Thr-J21-Glu-J23-J24-U25-J26- J27-J28-U29-J30-J31-Arg-J33-J34-J35-J36-B37-J38- J39-U40-J41-J42-J43-U44-J45-J46-J47-J48-J49-Arg- J51-U52-J53-J54-Asp-U56-Lys-Ser-Z59-Leu-J61-J62- J63-J64-Z65-J66-J67-U68-J69-J70-J71-U72-J73-J74-J75 in which the amino acids J are chosen independently of each other from natural amino acids, or derivatives thereof, in such a manner that at least 50% of them are polar residues chosen from Arg, Asn, Asp, Cys, Gln, Glu, Gly, His, Lys, Orn, Pro, Ser, Thr and Tyr, the amino acids U are chosen from Ala, Cys, Gly, Ile, Leu, Met, Phe, Trp, Tyr and Val, the amino acid X18 is chosen independently of the other amino acids of the sequence from Ala, Asn, Cys, Gln, Gly, His, Ile, Leu, Met, Phe, Ser, Thr, Trp, Tyr and Val, the amino acid B37 is chosen independently of the other amino acids of the sequence from Arg, Ala, Cys, Gly, Ile, Leu, Met, Phe, Trp, Tyr and Val, the amino acid Z7 is chosen independently of the other amino acids from Asp and Glu, the amino acids Z59 and Z65 are chosen independently from Glu, Asp, Lys and Arg, the superscripts of the residues J, Z, U, X and B representing the positions of these amino acids in the said sequence.