Technetium, the missing element

Abstract

The history of the discovery of technetium is reviewed within the framework of the discovery and production of artificial radioactivity in the twentieth century. Important elements of this history are the accidental production of this element in a cyclotron in Berkeley, California, USA, a machine devised by Ernest Orlando Lawrence, and its subsequent discovery in 1937 by Carlo Perrier and Emilio Segrè in scrap metal parts sent by Lawrence to Palermo, Italy by mail. A detailed account is given of the steps taken; the history of the later discovery of the technetium-99m isotope in 1938 is likewise examined. Sources of natural and artificial technetium are briefly discussed.

Bone Scans Are Reliable for the Identification of Lumbar Disk and Facet Pathology

“…Tc 99m has a half-life of 6.02 hours 21 and decays to the nonradioactive isotope Tc 99 , 22 which is eliminated through the urine and stool. 23 Hypersensitivity reactions to Tc 99m -HDP are extremely rare. The estimated effective radiation dose to a patient undergoing a Tc 99m -HDP bone scan is 2.5 milli-Sieverts (mSv).…”

The Astrophysical Processes of Cosmological Hydrogen that Generate the Chemical Elements that Make up the Universe

“…In the case of Tc and Pm, it has been demonstrated that the elements are and were produced by the normal nuclear reactions of stars, but since, their most stable isotopes have a relatively short half-life of 4.21 million years and 17.7 years [27] [28] respectively, by the time scientist are trying to detect them on the earth, there are almost no traces left. After the detection of the neutron star crash it is accepted that all the now called synthetic elements were also produced in that event, but they are not detectable on the earth because of their short half-lives [29].…”

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“…Whereas [ 99m TcO 4 ] -has been used for thyroid imaging since the 1960s, the preparation of more specific compounds for functional imaging was the incentive which boosted technetium chemistry over the following decades. [25,26] This research comprised all fields; organometallic chemistry and coordination chemistry, thermodynamics and kinetics and even catalysis was an issue. The motivation, however, was mainly the discovery of new imaging agents.…”