Full-body scan, also known as a full-body CT scan, involves a CT scan of the patient's entire body to support the diagnosis and treatment of specific illnesses.
History and overview
CT scans were first used in medicine in the 1970s, and they now play an important role in diagnosis in medicine. Controversy arises from the use of CT scans in the screening of patients who have not been diagnosed with a disease, or who do not have symptoms suggestive of a disease, due to the low rate of finding disease, and the inconclusiveness of the cause of abnormalities seen.
As with any test that screens for disease, the risks of full-body CT scans, (including radiation, incidental or wrong diagnosis, and a false sense of security in a test with error), need to be outweighed by the benefit of identifying a treatable disease at an early stage. One of the risks of a full body CT scan is the relatively high doses of radiation. Conventional CT scanners may expose patients to 10 mSv of radiation, or over a hundred times that of a chest x-ray. However, the radiation risk of CT scanners used for screening may be less than this, and depends upon the mathematical model used for calculation. Additional risks include the possible identification of incidental abnormalities of unclear significance. This may lead to further unnecessary testing, which may be invasive.
Cost is an additional disadvantage; at a cost of US$600 to $3000 full-body scans are expensive, and are rarely covered by insurance.
Other CT scans may be used in screening for disease in high risk groups. These scans are more localized and are identical to those used in the course of treating a disease, the only difference being that these scans are done before any disease is found.
Low-dose CT scanning of the lungs may be done to screen for lung cancer, but it has showed varied success.  CT colography, or virtual colonoscopy is a CT scan that looks for polyps that may develop into colon cancer. It has shown detection rates for polyps of size greater or equal to 8 mm that are comparable to traditional or "optical" colonoscopy. One of the downsides of imaging is that although they provide comparable detection rates, they have no inherent capability of treatment. For example, if polyps are found on virtual colonoscopy the next step is to perform a traditional colonoscopy to remove the polyps.
Other types of scans include Heart, Brain, Bone density, Angiogram, Carotid artery.  
Magnetic resonance imaging (MRI) scans are associated with a lesser radiation risk than CT scans, and are being evaluated for their use in screening.
In popular culture
- In the episode "Role Model" of the TV show House the lead character Dr. Gregory House refers to full-body scans as "useless" because they could find several things wrong in anybody.
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