A radioconjugate consisting of the somatostatin analog octreotate labeled with lutetium Lu 177 with receptor ligand, beta-emitting radioisotope, and potential antineoplastic activities. Lutetium Lu 177-DOTA-octreotate binds to somatostatin receptors (SSTRs), especially type 2 receptors, present on the cell membranes of many types of neuroendocrine tumor cells. Upon binding and internalization, this radioconjugate specifically delivers a cytotoxic dose of beta radiation to SSTR-positive cells. Lutetium Lu 177-DOTA-octreotate is produced by substituting the natural amino acid Thr for the alcohol Thr(ol) at the C terminus of the somatostatin analog octreotide and chelating the octreotate to Lu 177 via dodecanetetraacetic acid (DOTA).