A radioconjugate consisting of the octreotide derivative edotreotide (Tyr3-octreotide or TOC) labelled with lutetium Lu 177 with receptor ligand, beta-emitting radioisotope, and potential antineoplastic activities. Similar to the somatostatin analogue octreotide, lutetium Lu 177-edotreotide binds to somatostatin receptors (SSTRs), especially type 2 receptors, present on the cell membranes of many types of neuroendocrine tumour cells. Upon binding and internalization, this radioconjugate specifically delivers a cytotoxic dose of beta radiation to SSTR-positive cells. Lutetium Lu 177-edotreotide is produced by substituting tyrosine for phenylalanine at the 3 position of the somatostatin analogue octreotide and chelating the substituted octreotide to Lu 177 via dodecanetetraacetic acid (DOTA).