radioactive isotope

Also found in: Dictionary, Thesaurus, Encyclopedia.


a chemical element having the same atomic number as another (i.e., the same number of nuclear protons), but having a different atomic mass (i.e., a different number of nuclear neutrons).
radioactive isotope radioisotope.
stable isotope one that does not transmute into another element with emission of corpuscular or electromagnetic radiations.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.

ra·di·o·ac·tive i·so·tope

an isotope with an unstable nuclear composition; such nuclei decompose spontaneously by emission of a nuclear electron (β particle) or helium nucleus (α particle) and radiation (γ rays), thus achieving a stable nuclear composition; used as tracers and as radiation and energy sources. See: half-life.
Farlex Partner Medical Dictionary © Farlex 2012

radioactive isotope

Radionuclide, see there.
McGraw-Hill Concise Dictionary of Modern Medicine. © 2002 by The McGraw-Hill Companies, Inc.

radioactive isotope

Collins Dictionary of Biology, 3rd ed. © W. G. Hale, V. A. Saunders, J. P. Margham 2005

Radioactive isotope

One of two or more atoms with the same number of protons but a different number of neutrons with a nuclear composition. In nuclear scanning, radioactive isotopes are used as a diagnostic agent.
Gale Encyclopedia of Medicine. Copyright 2008 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
The data also reveal that regular measurements of radiation exposure and radiation protective measures need not be undertaken in theatres where surgeons are working with radioactive isotopes regularly.
where dN/dt is the rate of decay of a radioactive isotope, N is the present amount of a radioactive isotope (called the parent) in a sample, [N.sub.0] is the amount of parent isotope in the sample at the time of its formation, t is the age of the sample, and [lambda] is the decay constant of the parent isotope.
The calling card in the Litvinenko assassination was that radioactive isotope. It says, "Make no mistake, we did this."
a = decay constant, which is unique for each radioactive isotope
A 74-year-old prostate cancer patient recently received the first brachytherapy seed implant ever to use the radioactive isotope cesium 131.
The sites with guano registered ten times the concentration of the radioactive isotope cesium-137, which does not occur naturally but has been released into the atmosphere through nuclear testing and reactor meltdowns.
"Gamma ray technology uses the radiation given off by a radioactive substance, typically Cobalt 60, which is a radioactive isotope of the element cobalt," Masefield explains.
a monocolonal antibody or a peptide) is connected to a powerful radioactive isotope. As it radioactively decays, the isotope emits particles that can either directly or indirectly kill any cancer cells it encounters.
Researchers at Canada's national particle accelerator, TRIUMF, recently announced that they have successfully simulated the reaction of the unstable, radioactive isotope sodium 21 during nova and other cataclysmic stellar events, bringing them one step closer to understanding how matter is produced in the universe.
All XRF instruments have an excitation source such as an x-ray tube or radioactive isotope. The key difference lies in how the x-rays get into the detector.
17 Kyodo A former Osaka University researcher Tuesday was sentenced to two years' imprisonment, suspended for three years, for spreading a radioactive isotope on the floor of a laboratory in June last year.

Full browser ?