Positron Emission Tomography

Positron Emission Tomography (PET), in nuclear medicine, technique for imaging internal body tissues. PET requires a cyclotron as an on-site source of short-lived positron-emitting isotopes. The isotopes are injected into the patient along with a glucose-related compound, and the positrons collide with electrons in body tissues to produce photons. The photons are tracked by a tomographic scintillation counter, and the information is processed by a computer to provide both images and data on blood flow and metabolic processes within the tissues observed. PET scans are particularly useful for diagnosing brain tumors and the effect of strokes on the brain, along with various mental illnesses. They are also used in brain research and the mapping of brain functions. See also Radiology.