PET (Positron Emission Tomography)

Positron Emission Tomography (PET) is a molecular imaging modality which produces images of the body by detecting the radiation emitted from radioactive substances. These substances are injected into the body, and are usually tagged with a radioactive atom, such as carbon-11, fluorine-18, oxygen-15 or nitrogen-13, that has a short decay time. These radioactive atoms are formed by bombarding normal chemicals with neutrons to create short-lived radioactive isotopes.

PET detects the gamma rays given off at the site where a positron emitted from the radioactive substance collides with an electron in the tissue. PET is growing in importance because it can provide researchers with metabolic data about disease status.

PET measures the metabolic activity of cells in the human body. It provides valuable information on the biochemical and biological activity inside a living subject in a non-invasive way, combining techniques that are applied in nuclear medicine with the precise localization that is achieved by computerized image reconstruction.

As a biological imaging examination, PET can detect and stage tumors, often before they are visible through other conventional examinations. In addition, PET can provide doctors with important early information about heart disease or several neurological disorders such as Alzheimer’s, Parkinson’s, epilepsy and dementia. Biochemical processes change with disease and may be altered before there is a change in gross anatomy. PET is able to detect extremely small cancers and very subtle changes of function in the brain and heart, due to disease-related modifications in tissue perfusion or cell metabolic rates.