| abstract |
Radioactive-technetium-labelled and radioactive-rhenium-labelled somatostatin derivatives are disclosed for the selective detection/localisation or for the selective therapeutic treatment of tumours with somatostatin receptors. The labelled polypeptides are characterised by the general formula: R1-S1-A1-A2-(D)Trp-A3-A4-A5-Thr-S2-R2, wherein R1 is a hydrogen atom or a C1-C4 alkylcarbonyl group, R2 is an amino group, a hydroxy group or a C1-C4 alkoxy group, A1 and A5 each independently are Phe, MePhe, EtPhe, Tyr, Trp, Nal (naphthylalanyl), or Cys, A2 is Phe, MePhe, EtPhe, Tyr, Trp or Nal, A3 is Lys, MeLys or (ε-Me)Lys, A4 is Thr or Val, S1 is an amino acid sequence of 1 to 6 amino acids, selected from the group consisting of Ala, Cys, Asn, Phe, MePhe, EtPhe, Tyr, Trp, Nal, Gly, Lys, MeLys, (ε-Me)Lys, Thr, Val, Asn and Ser, and S2 is an amino acid sequence of 0 to 3 amino acids selected from the group mentioned sub S1, with the proviso that the polypeptide comprises two cysteine amino acid radicals, the metal-radionuclide being selected from a radioactive Tc or Re isotope which, as a cation, is bound covalently to the mercapto groups of the cysteine amino acid radicals. |