positroniittomografiaa

Positroniittomografiaa, often abbreviated as PET, is a nuclear medicine imaging technique used to observe metabolic processes in the body. It is a type of positron emission tomography scan. A small amount of a radioactive tracer is introduced into the body, usually injected into a vein. This tracer is designed to accumulate in specific organs or tissues, and it emits positrons. When a positron encounters an electron, they annihilate each other, producing two gamma rays that travel in opposite directions. The PET scanner detects these gamma rays and uses computer processing to create a three-dimensional image of the distribution of the tracer within the body.

PET scans are widely used in medical diagnostics, particularly in oncology, neurology, and cardiology. In cancer detection, PET can identify areas of increased metabolic activity, which often corresponds to tumors, even before structural changes are visible on other imaging modalities. In neurology, PET is used to study brain function, aiding in the diagnosis of conditions like Alzheimer's disease, Parkinson's disease, and epilepsy by measuring glucose metabolism or blood flow in the brain. In cardiology, PET can assess myocardial perfusion and viability, helping to diagnose and manage heart disease. The choice of radioactive tracer depends on the specific application, with fluorine-18 fluorodeoxyglucose (FDG) being the most common for general metabolic imaging. The procedure is generally safe, with the radiation dose from the tracer being relatively low and quickly eliminated from the body.