Definition of "technetium" []

• A silvery-gray radioactive metal, the first synthetically produced element, having 14 isotopes with masses ranging from 92 to 105 and half-lives up to 4.2 × 106 years. It is used as a tracer and to eliminate corrosion in steel. Atomic number 43; melting point 2,200°C; specific gravity 11.50; valence 0, 2, 4, 5, 6, 7. See Table at element. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "This test uses very small amounts of a radioactive tracer called technetium to view the liver and spleen."
• "This test, also called a technetium sulfur colloid scan, or a liver-spleen scan, is seldom done, but I find it useful in some circumstances, especially if I think my patient may have a condition called focal nodular hyperplasia (FNH) (see pages 223-25)."
• "Together, these two reactors produce about 60 per cent of the world's supply of an isotope called technetium 99, a radioactive substance used in 85 per cent of diagnostic imaging procedures."