Tc, or technetium, is a chemical element with the symbol Tc and atomic number 43. It is a silvery-gray metal that is part of the transition metals group in the periodic table. Technetium is notable for being the first artificially produced element, discovered in 1937. It has no stable isotopes, and its most common isotope, Tc-98, is used in various applications, particularly in medical imaging. In medicine, Tc is widely used in nuclear medicine for diagnostic imaging. Its radioactive properties allow it to be used in radiopharmaceuticals, which help visualize organs and tissues in the body. This makes technetium essential for procedures like SPECT (Single Photon Emission Computed Tomography) scans, aiding in the diagnosis of conditions such as cancer and heart disease.