Positronemissioontomograafia

Positronemissioontomograafia, commonly known as PET, is a nuclear medicine imaging technique that produces three-dimensional images of metabolic processes within the body. It works by detecting pairs of gamma rays emitted indirectly by a positron-emitting radionuclide, or radiotracer, that is introduced into the body on a biologically active molecule. Commonly, this molecule is fluorodeoxyglucose (FDG), a glucose analog. Once injected, the radiotracer travels through the body and accumulates in areas of high metabolic activity. When a positron is emitted from the radionuclide, it quickly encounters an electron, resulting in annihilation and the production of two gamma rays traveling in opposite directions. The PET scanner, a ring of detectors, captures these gamma rays. By analyzing the timing and location of these detected gamma ray pairs, a computer can reconstruct images showing where the radiotracer has concentrated, thus revealing areas of increased metabolic activity. PET scans are widely used in oncology to detect cancer, determine its stage, and monitor treatment effectiveness, as well as in neurology to study brain function and diagnose conditions like Alzheimer's disease and epilepsy, and in cardiology to assess blood flow to the heart muscle.