molibdén99

Molibdén99, in common scientific usage, refers to molybdenum-99 (99Mo), a radioactive isotope of the element molybdenum (atomic number 42). It has a mass number of 99 and decays primarily to technetium-99m (99mTc) with a half-life of about 66 hours. The 99mTc produced from this decay is a metastable state that emits gamma radiation suitable for diagnostic imaging. Because of its favorable imaging properties and short radiation exposure, 99mTc-based radiopharmaceuticals underpin a large portion of modern nuclear medicine.

Production and use: Most 99Mo is produced in nuclear reactors by irradiating uranium targets in the fission process or by neutron irradiation of molybdenum targets, followed by chemical separation to isolate the 99Mo. In clinical settings, 99Mo serves as the parent nuclide for 99mTc in a generator system called the 99Mo/99mTc generator. The 99mTc is then delivered to imaging departments where it is bound to various pharmaceutical compounds to create radiotracers used in single-photon emission computed tomography (SPECT). 99mTc radiopharmaceuticals cover a wide range of diagnostic applications, including bone, cardiac, and renal scans, and account for a large share of nuclear medicine procedures worldwide.

Supply and safety: The 99Mo supply chain has historically depended on a relatively small number of reactors, making it vulnerable to outages and geographic constraints. As a result, there have been ongoing efforts to diversify production, including the use of low-enriched uranium targets and accelerator-based approaches. Production and use are subject to strict safety, regulatory, and waste-management controls to protect workers and patients from radiation exposure.

See also: molybdenum-99/technetium-99m generator, nuclear medicine, radiopharmaceuticals.