positron emission tomography
- the process of producing a PET scan. Cf. PET scanner.
* * *▪ imaging techniqueimaging technique used in diagnosis and biomedical research. It has proved particularly useful for studying brain and heart functions and certain biochemical processes involving these organs (e.g., glucose metabolism and oxygen uptake). In PET a chemical compound labeled with a short-lived positron-emitting radionuclide of carbon, oxygen, nitrogen, or fluorine is injected into the body. The activity of such a radiopharmaceutical is quantitatively measured throughout the target organs by means of photomultiplier-scintillator detectors. As the radionuclide decays, positrons are annihilated by electrons (electron), giving rise to gamma rays (gamma ray) that are detected simultaneously by the photomultiplier-scintillator combinations positioned on opposite sides of the patient. The data from the detectors are analyzed, integrated, and reconstructed by means of a computer to produce images of the organs being scanned.PET has become a valuable tool in the detection of cancer and cancer metastasis (spread) and in the evaluation of heart conditions. PET studies have helped scientists understand more about how drugs (drug) affect the brain and what happens during learning, when using language, and in certain brain disorders, such as stroke, depression, and Parkinson disease (parkinsonism). In addition, scientists are working to find ways to use PET to identify the biochemical nature of neurological disorders and mental disorders (mental disorder) and to determine how well therapy is working in patients. PET has revealed marked changes in the depressed brain, and knowing the location of these changes helps researchers understand the causes of depression and monitor the effectiveness of specific treatments.
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Positron emission tomography — (PET) is a nuclear medicine imaging technique which produces a three dimensional image or map of functional processes in the body. The system detects pairs of gamma rays emitted indirectly by a positron emitting radionuclide (tracer), which is… … Wikipedia
positron-emission tomography — n tomography in which an in vivo, noninvasive, cross sectional image of regional metabolism is obtained by a usu. color coded cathode ray tube representation of the distribution of gamma radiation given off in the collision of electrons in cells… … Medical dictionary
Positron Emission Tomography — Tomographie par émission de positons Pour les articles homonymes, voir TEP. Reconstruction tridimensionnelle de la distribution de glucose marqué au fluor 18 telle que mesurée par tomographie d émission de positons La tomographie … Wikipédia en Français
positron emission tomography — noun using a computerized radiographic technique to examine the metabolic activity in various tissues (especially in the brain) • Syn: ↑PET • Hypernyms: ↑imaging, ↑tomography * * * the process of producing a PET scan. Cf. PET scanner. * * *… … Useful english dictionary
positron emission tomography — pozitroninė tomografija statusas T sritis Standartizacija ir metrologija apibrėžtis Tomografija, kai įvairiomis kryptimis užregistruota pozitronų ir elektronų susidūrimo sukelta gama spinduliuotė apdorojama kompiuterinėmis programomis taip, kad… … Penkiakalbis aiškinamasis metrologijos terminų žodynas
positron emission tomography — (PET, positron emission computed tomography, PECT) a technique in nuclear medicine for cross sectional imaging that enables a noninvasive assessment and localization of metabolic activity to be made. Emission of a positron by a radioisotope… … Medical dictionary
positron emission tomography — (PET) tomography accomplished by detection of gamma rays emitted from tissues after administration of a natural biochemical substance (e.g., glucose, fatty acids) into which positron emitting isotopes have been incorporated. The paths of the… … Medical dictionary
positron-emission tomography — noun Date: 1976 tomography in which a cross sectional image of regional metabolism is obtained by a usually color coded representation of the distribution of gamma radiation given off in the collision of electrons in cells with positrons emitted… … New Collegiate Dictionary
Positron Emission Tomography — technique for creating detailed images of bodily tissues by injecting positron laden material into the body and recording the gamma rays emitted over a period of about two hours (Medicine) … English contemporary dictionary
positron emission tomography — noun tomography which relies on radioactive tracers injected into the patient, so as to detect abnormal biochemical activity. Also, PET … Australian English dictionary