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PET scan(pĕt) or
positron emission tomography(pŏz`ĭtrŏn' ĭmĭsh`ən təmŏg`rəfē), a medical imaging technique that monitors metabolic, or biochemical, activity in the brain and other organs by tracking the movement and concentration of a radioactive tracer injected into the bloodstream. The technique uses special computerized imaging equipment and rings of detectors surrounding the patient to record gamma radiationgamma radiation,
high-energy photons emitted as one of the three types of radiation resulting from natural radioactivity. It is the most energetic form of electromagnetic radiation, with a very short wavelength (high frequency).
..... Click the link for more information. produced when positrons (positively charged particles) emitted by the tracer collide with electrons.
PET scans are especially valuable in imaging the brain. They are used in medicine to diagnose brain tumors and strokes, and to locate the origins of epileptic activity; in psychiatry to examine brain function in schizophreniaschizophrenia
, group of severe mental disorders characterized by reality distortions resulting in unusual thought patterns and behaviors. Because there is often little or no logical relationship between the thoughts and feelings of a person with schizophrenia, the disorder has
..... Click the link for more information. , bipolar disorderbipolar disorder,
formerly manic-depressive disorder
severe mental disorder involving manic episodes that are usually accompanied by episodes of depression.
..... Click the link for more information. , and other mental illnesses; and in neuropsychology to study such brain functions and capabilities as speech, reading, memory, and dreaming.