Technetium-99m ion (Tc-99m)

Technetium-99m (Tc-99m) is a synthetic, metastable nuclear isomer of technetium used almost exclusively as a radioactive tracer in nuclear medicine diagnostic procedures. Widely valued for its physical properties—a half-life of approximately 6 hours, predominant emission of 140 keV gamma rays (ideal for detection by gamma cameras), and versatile coordination chemistry that allows it to be incorporated into a wide range of biologically active molecules—Tc-99m enables non-invasive imaging of organs such as the brain, heart, bones, thyroid, kidneys, liver, and others. It is not a naturally occurring molecule in living systems and is not considered a molecular biological target such as a receptor or enzyme. Its role is purely as an imaging agent when complexed with specific molecules that govern its biodistribution and organ targeting.

Other names

Tc-99m99mTcTechnetium-99mPertechnetate ion (for TcO₄⁻)

Not a target; radiotracer incorporated into molecules for gamma emission-based imaging