Positron Emission Tomography

Positron emission tomography is a medicine imaging technique that produces a three-dimensional image or picture of functional processes in the body by detecting the radiation emitted from radioactive substances. It uses a special type of camera and a tracer to look at organs in the body. The system works by detecting pairs of gamma rays emitted indirectly by a positron-emitting radionuclide (tracer), which is introduced into the body on a biologically active molecule. Three-dimensional images of tracer concentration within the body are then constructed by computer analysis.

To conduct the scan, a short-lived radioactive tracer isotope is injected into the living subject (usually into blood circulation). The tracer is chemically incorporated into a biologically active molecule and put under scanner of gamma ray detector with crystals embedded in it.

The crystals convert the gamma rays, emitted from the patient, to photons of light, and the photomultiplier tubes in the apparatus convert and amplify the photons to electrical signals. These electrical signals are then processed by the computer to generate images. Study the brain’s blood flow and metabolic activity. A PET scan used to detect nervous system problems, such as Alzheimer’s disease, Parkinson’s disease, schizophrenia, cancers of the head and neck, brain, lung, colon, or prostate etc.