Where does Technetium-99 come from?
Technetium-99 is produced in commercial quantities mainly as a byproduct from the operation of nuclear reactors. Most of the Tc-99 produced in a nuclear reactor originates from the fission of uranium-235. The Tc-99 produced in the reactor may become part of its airborne, liquid, or solid wastes. In addition to being produced in nuclear reactors, Tc-99 is produced in the detonation of nuclear weapons. Medical and academic institutions use molybdenum/technetium generators as a source of Tc-99m for diagnostic tests or research. In this case, the nuclear reactor provides the radioactive parent, molybdenum-99, for the technetium generator. Molybdenum-99 has a short (66 hour) half-life, and decays to the even shorter-lived (6 hrs) Tc-99m.
