Metello, Luis F.2022-05-182022-05-182015-06Metello, L. F. (2015). 99mTc-Technetium Shortage: Old Problems Asking for New Solutions. Journal of Medical Imaging and Radiation Sciences, 46(3), 256-261. https://doi.org/https://doi.org/10.1016/j.jmir.2015.07.003http://hdl.handle.net/10400.22/20539Technetium 99-metastable (99mTc) is the most important radionuclide, responsible for more than 80% of applications in nuclear medicine, with more than 40 million procedures being performed each year, worldwide, in all major clinical fields. It decays with a half-life of 6.01 hours by isomeric tran sition to 99gTc, thereby emitting 140 keV gamma photons. This energy almost ideally meets the maximum sensitivity of single photon emission computed tomography (SPECT) cam era systems. In addition, the rich complex chemistry of Techne tium allows the incorporation of the radioisotope into a wide variety of ligands stabilizing the radionuclide at different oxida tion states. Thus, since the early 60s, hundreds of radiopharma ceuticals labeled with 99mTc have been developed, and some have gained significant market success. However, the main reason for the special role of Technetium in SPECT is probably the cost effectiveness and the on-demand worldwide availability of the isotope through the 99Mo/99mTc generator systems.engNuclear medicineRadionuclideother10.1016/j.jmir.2015.07.003