Lutetium177

Lutetium-177, symbol 177Lu, is a radioactive isotope of lutetium with a half-life of about 6.647 days. It decays by beta minus emission to hafnium-177 and also releases gamma photons that enable post-therapy imaging. The beta radiation provides a therapeutic dose to targeted tissues, while gamma rays allow imaging to monitor distribution and dosimetry during treatment.

Production and use in medicine: 177Lu is typically produced in a nuclear reactor by irradiating lutetium-176 targets, yielding carrier-added or higher specific activity forms that can be bound to chelators for biological targeting. In radiopharmacy, 177Lu is attached to molecules such as DOTA to create radiopharmaceuticals that deliver radioactivity to specific receptors or cellular targets.

Prominent radiopharmaceuticals: Lutetium-177 DOTATATE (Lutathera) is used for somatostatin receptor–positive gastroenteropancreatic neuroendocrine tumors. In clinical use, a typical regimen is 7.4 GBq every 6 weeks for up to 4 cycles. Lu-177–PSMA-617 (Pluvicto) is approved for metastatic castration-resistant prostate cancer after at least one systemic therapy, given as 7.4 GBq every 6 weeks for up to 6 cycles. Both agents illustrate the expanding field of targeted radionuclide therapy, combining tumor specificity with radiative treatment.

Safety and regulatory considerations: Lu-177 therapies require specialized facilities and protocols to protect patients, staff, and the public from radiation exposure. Common adverse effects include hematologic suppression, nausea, and potential renal toxicity, mitigated by kidney protection regimens and careful patient selection.