positron emission tomography

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun Tomography in which a computer-generated image of local metabolic and physiological functions in tissues is produced through the detection of gamma rays that are emitted when introduced radionuclides decay and release positrons.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A medical imaging technique which detects the gamma rays produced by positrons emitted from injected radionuclides.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun using a computerized radiographic technique to examine the metabolic activity in various tissues (especially in the brain)