Technetium-99m radiopharmaceuticals for in vivo diagnostics

Technetium-99m is an ideal radionuclide with optimum decay characteristics. It can be obtained in sterile, pyrogen-free and carrier-free condition, as sodium pertechnetate (Na99mTcO4), from 99Mo/99mTc generator. Because of its six-hour physical half-life and monochromatic 140 keV photons free of -radiation, administration of small amounts of 99mTc solution is possible, without a significant radiation damage to the patient. Technetium eluted from the 99Mo/99mTc generator is in the highest oxidation form (+ 7). It can be used for diagnostic purposes alone, but it is often used for labeling different organic and inorganic compounds. As it is unreactive, reduction with a chemical reductant, (+1), (+3) and (+5) oxidation are necessary before use. Nowadays almost 80% of radiopharmaceuticals are based on 99mTc.