Somatostatin analogues that all somatostatin receptors bind and use.

Somatostatin analogues of the general formula: (See formula) wherein: Z may be absent or present and when present, is selected from the group consisting of chelating agents based on DOTA and DTPA chelating agents based NOTA, compounds carbonyl, hydrazino nicotinamide (hynic), N4-chelators, desferrioxamine, NxSy-chelators, all optionally complexed p labeled with a radioisotope, tyrosine (Tyr) for halogenation, a fluorescent dye or biotin; L may or not present and is a linker molecule; X1 is a symmetric or asymmetric diamino acid, containing 3 or 4 consecutive C atoms with a linker to the chelating agent, for example, acid D / L-diaminobutyric (D / L-Dab) for a more basic character or D / L -Glu for coupling to primary and secondary amino groups; X2 is a natural or unnatural positively charged amino acid or arginine mimic or citrulline, or a neutral amino acid like Asn; X3 is phenylalanine (Phe), Ala- [3- (2-thienyl)] or alpha-, beta-naphthylalanine; X4 is an aromatic amino acid, optionally halogenated, in particular with Cl, Br, I or 18F; X5 is threonine (Thr) or serine (Ser); and X6 is phenylalanine (Phe), Ala- [3- (2-thienyl)] or alpha-, beta-naphthylalanine.