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A positron emission tomography (PET) scan is a special kind of imaging test that allows medical professionals to see how certain tissues and organs within the body are functioning. The most significant difference between a PET scan and other imaging tests, such as MRI or CT scan, is the ability to detect changes in the body at the cellular level rather than after a disease has progressed enough to actually effect the surrounding tissue or organs. A scan may be useful for helping to detect certain types of cancer, brain disorders, heart problems, and other conditions of the central nervous system.
A PET scan is performed by injecting a small amount of radioactive chemical into a vein. As the chemical travels through the body, it is absorbed by the organs and tissues. During the test, a scanner records the energy produced by the cells. A computer converts the recording into three-dimensional pictures of an area of the body and any cells that are changing show up at a brighter contrast to any surrounding, normal cells.
There is very little preparation involved prior to the procedure, and it is most often done on an outpatient basis. In general, most patients are simply given restrictions on food or drink for six to 12 hours prior to the test. Heart patients, diabetics, and other specific patients may be given a specific set of directions depending on the purpose of the scan. The test takes approximately two hours to complete.
PET scan technology is widely used in oncology as it helps to stage and detect certain types of cancer including breast cancer, lymphoma, and certain types of lung cancer. It is also widely used in medical research.
Due largely to the technology and equipment involved, this type of scan is considerably more expensive than conventional imaging tests, but most insurance plans will cover one if certain conditions apply. Before undergoing the scan, patients should check with their insurance company about coverage benefits and requirements.