Positron Emission Tomography
Positron Emission Tomography[edit | edit source]
Positron Emission Tomography (PET) is a nuclear medicine functional imaging technique that is used to observe metabolic processes in the body. The system detects pairs of gamma rays emitted indirectly by a positron-emitting radionuclide, which is introduced into the body on a biologically active molecule.
Principle of PET[edit | edit source]
PET works by using a radioactive tracer that emits positrons. When a positron encounters an electron, they annihilate, producing a pair of gamma photons that travel in opposite directions. These photons are detected by the PET scanner, which uses this information to construct detailed images of the body's internal processes.
Applications of PET[edit | edit source]
PET is widely used in oncology to detect and monitor cancer, as it can reveal the metabolic activity of tumors. It is also used in neurology to study brain disorders such as Alzheimer's disease, epilepsy, and Parkinson's disease. In cardiology, PET can assess myocardial perfusion and viability.
PET Tracers[edit | edit source]
The most commonly used tracer in PET is fluorodeoxyglucose (FDG), a glucose analog that accumulates in high-energy consuming cells such as cancer cells. Other tracers include carbon-11, nitrogen-13, and oxygen-15, each used for different types of studies.
Advantages of PET[edit | edit source]
PET provides unique information about the body's metabolic activity and function, which is not available through other imaging techniques like CT or MRI. It is particularly useful for detecting cancer, evaluating brain function, and assessing heart health.
Limitations of PET[edit | edit source]
PET scans are expensive and involve exposure to radiation. The resolution of PET images is lower than that of CT or MRI, and the availability of PET scanners is limited in some regions.
PET/CT and PET/MRI[edit | edit source]
To improve diagnostic accuracy, PET is often combined with computed tomography (CT) or magnetic resonance imaging (MRI). These hybrid systems provide both metabolic and anatomical information, enhancing the ability to diagnose and monitor diseases.
See Also[edit | edit source]
References[edit | edit source]
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