11c-labelled peptide for detecting diseased tissue which expresses a chemokine receptor

The use of a peptide (1) for producing an agent for detecting diseased tissue (18) which expresses a chemokine receptor (4) is described. The peptide (1) binds to the chemokine receptor (4) and has an 11 C carbon atom. Also described is a radiopharmacon for localizing diseased tissue (18) which expresses a chemokine receptor (4). This comprises a peptide (1) which binds to the chemokine receptor (4) and has an 11 C carbon atom.