Technetium-99m radiopharmaceuticals for in vivo diagnostics

Abstract

Technetiiim-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/99Tc 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. Radiopharmaceuticals. Radiopharmaceuticals are radionuclides or radioactive compounds used in diagnosis and therapy of human diseases. A pharmaceutical is chosen based on its localization in the organ, or its participation in its physiological function. Radiation emitted from a radionuclide is detected by a radiation detector. The ability to incorporate available radionuclides into tracer molecules has been the main goal in developing radiopharmaceuticals. As radionuclides with nuclear characteristics used as either diagnostic or therapeutic radiopharmaceuticals, are predominantly metals, they can be designed as metal essential, whereby biological distribution is determined by coordination compound, or metal tagged, in which case the properties of the carrier molecule (ligand system) determine the biological distribution. This paper reviews the development of 99mTc-radiopharmaceuticals. .