: a metallic element that is obtained by bombarding molybdenum with deuterons or neutrons and in the fission of uranium and that is used in medicine in the preparation of radiopharmaceuticals—symbol Tc; see pertechnetate; element table
Metallic chemical element, one of the transition elements, chemical symbol Tc, atomic number 43. All its isotopes are radioactive (seeradioactivity); some occur in trace amounts in nature as nuclear fission products of uranium. Its isotope technetium-97 was the first element artificially produced (1937; seecyclotron). Technetium-99, a fission product of nuclear reactors that emits gamma rays, is the most-used tracer isotope in nuclear medicine. Technetium resembles platinum in appearance and manganese and rhenium in chemical behaviour. It is also used as a metallurgical tracer and in corrosion-resistant products.