Lu177

Lutetium-177 (Lu-177) is a radioactive isotope of the element lutetium with a mass number of 177. It is produced artificially in nuclear reactors by neutron irradiation of stable lutetium-176 or, via indirect routes, to achieve higher specific activity. The nuclide is used in medicine because its decay provides both therapeutic beta radiation and diagnostic gamma emissions.

Lu-177 decays with a half-life of about 6.65 days by beta minus emission to hafnium-177. It also emits gamma photons, the most notable being lines near 113 keV and 208 keV, which enable coincidence imaging and dosimetry alongside therapy. The beta component delivers cytotoxic dose to targeted cells, while the gamma rays permit noninvasive tracking of distribution in the body.

In medical practice, Lu-177 is used in targeted radionuclide therapy. The most widely known radiopharmaceuticals are lutetium-177 DOTATATE and lutetium-177 PSMA-617, which are designed to bind to somatostatin receptors and prostate-specific membrane antigen, respectively. These agents deliver radiation selectively to tumor cells while limiting exposure to normal tissue. Lu-177 therapies are used for certain neuroendocrine tumors and metastatic prostate cancer, among other indications.

Production methods influence the specific activity of Lu-177. Direct neutron irradiation of lutetium-176 yields carrier-added Lu-177, whereas indirect routes via ytterbium-176 can produce higher specific activity Lu-177 after decay of the precursor. After production, Lu-177 is incorporated into chelated compounds under controlled conditions for clinical use.

Safety and regulatory oversight are essential due to the radiological nature of Lu-177. Treatments are administered in specialized facilities with appropriate shielding, monitoring, and dosimetry to manage radiation exposure to patients, caregivers, and medical staff.