Radionuclide generators

Abstract

The concept of radionuclide generator as a useful source of radionuclide for tracing biological and chemical processes was developed at the beginning of the 20th century but gained prominence only in the 1950s with the introduction of the first molybdenum-99 (Mo-99)/technetium-99m (Tc-99m) radionuclide generator. The factors that have contributed to its success include rather simple and effective separation chemistry of these parent and daughter elements, the physical parameters of Tc-99m, which are ideal for imaging in gamma radiation scanners, and the versatile chemistry of technetium allowing its coordination binding to various ligands. These factors combined led to the rapid uptake of Mo-99/Tc-99m generators and revolutionized the field of nuclear medicine. Nowadays, diagnostic imaging procedures with Tc-99m radiopharmaceuticals account for approximately 80% of diagnostic nuclear medicine procedures conducted worldwide. Several radionuclide generator systems have been introduced in clinical settings. An example is germanium-68 (Ge-68)/gallium-68 (Ga-68) generator, which is quickly gaining importance in diagnostic imaging by PET (Positron Emission Tomography), similarly to the Tc-99m generators in SPECT (Single Photon Emission Tomography).