Technetium is an artificial element, which has a metastable nuclear isomer (99mTc) with ideal radiation properties for use in nuclear medicine (low energy gamma radiation, essentially no particle emission, half-life of 6 h). 99mTechnetium is readily available from a generator system.

Currently, ca. 80% of all diagnosis in nuclear medicine are carried out using technetium.

Tc-radiopharmaceuticals can be used for the examination of the kidneys, the liver, the brain, the heart, the thyroid gland or the skeleton.