11C-labeled peptide for detection of a diseased tissue

There is provided the use of a peptide (1) for the preparation of an agent for detecting a diseased tissue (18) having a human leukocyte antigen (HLA) antigen complex (20) is described. In this case, the peptide (1) to an amino acid sequence of a complementarity determining region (CDR) of 3-loop (7) of a T-cell receptor (TCR) (6), which is directed against the HLA-antigen complex (20) and binds to an antigen (4) of the HLA-antigen complex (20). Furthermore, the peptide (1) on a Further, a radiopharmaceutical, describes the localization of a diseased tissue (18) which forms a HLA antigen complex (20) comprising such a peptide (1).