positron(redirected from Positrons)
Also found in: Dictionary, Thesaurus, Encyclopedia.
the antiparticle of the electron. When a positron is emitted by a radionuclide it combines with an electron and both undergo annihilation, producing two 511-keV gamma rays traveling in opposite directions. This effect is used in positron emission tomography.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.
A subatomic particle of mass and charge equal to the electron but of opposite (that is, positive) charge.
Synonym(s): positive electron
Farlex Partner Medical Dictionary © Farlex 2012
A subatomic particle of mass and charge equal to the electron but of opposite (i.e., positive) charge.
Medical Dictionary for the Health Professions and Nursing © Farlex 2012
One of the small particles that make up an atom. A positron has the same mass and amount of charge as an electron, but the positron has a positive charge.
Mentioned in: Positron Emission Tomography (PET)
Gale Encyclopedia of Medicine. Copyright 2008 The Gale Group, Inc. All rights reserved.