lutécium177

Lutetium-177 (177Lu) is a radioactive isotope of lutetium used in targeted radionuclide therapy. It decays by beta-minus emission with a half-life of about 6.647 days, delivering therapeutic radiation to targeted tissues. In addition to beta particles, 177Lu emits gamma photons (notably at 113 keV and 208 keV), which allow imaging of distribution and treatment monitoring through gamma cameras or SPECT.

Production and chemistry: 177Lu is produced in nuclear reactors by neutron irradiation of lutetium-176 (176Lu) via the Lu-176(n,gamma)Lu-177 reaction, or by irradiation of ytterbium targets followed by chemical separation. Chemically, lutetium behaves as Lu3+ and is incorporated into radiopharmaceuticals through chelators that bind the metal ion. Common forms include lutetium chelated to targeting molecules used in medicine, enabling selective delivery to tumors.

Medical applications: The principal use of 177Lu is targeted radionuclide therapy, particularly peptide receptor radionuclide therapy (PRRT) for neuroendocrine tumors. A well-known example is Lu-177 DOTATATE, used to treat somatostatin receptor–positive tumors. Lu-177–labeled ligands are also explored for radioligand therapy against other targets, including prostate-specific membrane antigen (PSMA), as in Lu-177–PSMA-617. Treatment aims to maximize dose to tumor tissue while minimizing exposure to healthy organs, with kidneys and bone marrow being key considerations in dosimetry and safety.

Safety and regulation: As a medical radiopharmaceutical, 177Lu requires specialized production, handling, and administration within licensed facilities. Its use is governed by national and international regulations to ensure safety and efficacy.