technetiumincluding

Technetium, symbol Tc, atomic number 43, is a transition metal in the periodic table. It was the first element to be produced artificially, discovered in 1937 by Carlo Perrier and Emilio Segrè, who created it by bombarding molybdenum with deuterons and isolating a radioactive product. The name derives from the Greek tekhnētikos, meaning artificial.

All of technetium's isotopes are radioactive; there are no stable isotopes. The most widely used is technetium-99m, a metastable state with a half-life of about 6 hours that emits a 140 keV gamma ray, suitable for medical imaging. Tc-99m is produced in Mo-99/Tc-99m generators, where a long-lived Mo-99 decays to technetium-99m for clinical use. Tc-99 itself has a half-life of about 211,000 years and occurs in very small quantities.

Chemically, technetium resembles manganese and rhenium, forming compounds in multiple oxidation states from -1 to +7. In solution, the pertechnetate anion TcO4- is common (+7). Tc forms many coordination compounds used in radiopharmaceuticals. In medicine, Tc-99m–labeled compounds enable imaging of bones, the thyroid, heart, and other organs, making it the backbone of many diagnostic procedures.

Occurrence and production: Technetium is extremely rare in the Earth's crust; virtually all practical supply is synthetic. It is produced in nuclear reactors or cyclotrons, typically from the fission of uranium-235 yielding Mo-99, which decays to Tc-99m, or by irradiation of molybdenum targets followed by separation.

Safety and regulation: Radiopharmaceuticals containing technetium are used under strict regulatory controls to minimize radiation exposure, with careful handling and waste disposal protocols.