Article summary provided by Shilpa Jais for discussion on 10/18:
Eckelman, WC. Unparalleled Contribution of Technetium-99m to Medicine over 5 Decades. JACC Cardiovasc Imag. 2009; 2: 364–368.
In this article, the history of technetium, specifically Tc-99m, is discussed. Technetium-99m is a radioactive tracer that can be detected in the body by medical equipment. It is used in about 85% of nuclear medicine procedures. Technetium was found in the 1930s. Before technetium, the radioisotopes of Iodine were used. However, they did not have the best characteristics for external imaging with the Anger camera, which is a device used to image gamma radiation emitting radioisotopes. Technetium has better nuclear properties for imaging with the Anger camera. It has a 140 keV gamma emission. The Mo-99/Tc-99m generator is a device used to extract the metastable isotope Tc-99m from a source of decaying Mo-99. The chemical form of Technetium made from the generator is pertechnetate. Pertechnetate cannot be used directly. A stannous ion is used as a reducing agent and added to a vial with the pertechentate and a targeting agent. Technetium is reduced and binds to the targeting agent in high yield. This process is the “instant” kit. With the use of the generator and the “instant” kit, the use of Tc-99m rose. Tc-99m is best used as a radiolabel for peptides. Tc-99m-targeted radio tracers are also used to watch the difference in target density as a function of disease progression or treatment.