PET scan

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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).
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 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
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, bipolar disorderbipolar disorder,
formerly manic-depressive disorder
or manic-depression,
severe mental disorder involving manic episodes that are usually accompanied by episodes of depression.
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, and other mental illnesses; and in neuropsychology to study such brain functions and capabilities as speech, reading, memory, and dreaming.

References in periodicals archive ?
Use of fluorodeoxyglucose positron emission tomography scans in patients with advanced germ cell tumour following chemotherapy: single-centre experience with long-term follow up.
The positron emission tomography scans tracked a radioactive form of the body fuel glucose to pinpoint which areas of the brain were most or least metabolically active.
Doctors and researchers use this isotope in positron emission tomography scans for cancer diagnosis and other purposes.
New studies using positron emission tomography scans (PET scans) and magnetic resonance imaging (MRI) found that the brains of people with ADHD and a related condition called hyperkinetic disorder (HKD) tend to have smaller than normal frontal lobes, basal ganglia, and other deep brain structures.
Researchers conducted positron emission tomography scans of the hearts of 29 Parkinson's patients to determine whether they also had a shortage of norepinephrine there.
The researchers used positron emission tomography scans to measure blood-flow changes in volunteers' brains while they read words.

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