- The property of some atomic nuclei of spontaneously emitting gamma rays or subatomic particles (α and β rays) by the process of nuclear disintegration and measured in disintegrations per second (dps). One dps is equal to 1 becquerel, and 3.7 × 1010 dps equals 1 curie.- artificial r. the r. of isotopes created by the bombardment of naturally occurring isotopes by subatomic particles, or high levels of x- or gamma radiation. SYN: induced r..- induced r. SYN: artificial r..
* * *ra·dio·ac·tiv·i·ty -ak-'tiv-ət-ē n, pl -ties the property possessed by some elements (as uranium) or isotopes (as carbon 14) of spontaneously emitting energetic particles (as electrons or alpha particles) by the disintegration of their atomic nuclei
* * *n.disintegration of the nuclei of certain elements, with the emission of energy in the form of alpha, beta, or gamma rays. As particles are emitted the elements 'decay' into other elements. Naturally occurring radioactive elements include radium and uranium. There are many artificially produced isotopes, including iodine-131 and cobalt-60 used in radiotherapy; technetium-99m is used in nuclear medicine. See radioisotope.• radioactive adj.
* * *ra·dio·ac·tiv·i·ty (ra″de-o-ak-tivґĭ-te) 1. emission of corpuscular or electromagnetic radiations consequent to nuclear disintegration, a natural property of all chemical elements of atomic number above 83; this can also be induced in all other known elements. 2. the quality of having such emissions.
Medical dictionary. 2011.