Full-body scan

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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,[1] 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,[2] due to the low rate of finding disease, and the inconclusiveness of the cause of abnormalities seen.[3][4]

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.[5] One of the risks of a full body CT scan is the relatively high doses of radiation.[6] Conventional CT scanners may expose patients to 10 mSv of radiation, or over a hundred times that of a chest x-ray.[7] However, the radiation risk of CT scanners used for screening may be less than this, and depends upon the mathematical model used for calculation.[6][8] 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.[9][10]

Other scans

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.[11] [12] 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.[13]

Other types of scans include Heart, Brain, Bone density, Angiogram, Carotid artery. [1] [2]

Magnetic resonance imaging (MRI) scans are associated with a lesser radiation risk than CT scans, and are being evaluated for their use in screening.[14]

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.

References

  1. Hounsfield GN. (1976). "Historical notes on computerized axial tomography". J Can Assoc Radiol. 27 (3): 135–142. PMID 789383. Unknown parameter |month= ignored (help)
  2. Brant-Zawadzki MN (2005). "The role of computed tomography in screening for cancer". Eur Radiol. 15 Suppl 4: 52–54. PMID 16479647. Unknown parameter |month= ignored (help)
  3. Berlin L (2003). "Potential legal ramifications of whole-body CT screening: taking a peek into Pandora's box". AJR Am J Roentgenol. 180 (2): 317–322. PMID 12540423. Unknown parameter |month= ignored (help)
  4. MacLean CD (1996). "Principles of cancer screening". Med Clin North Am. 80 (1): 1–14. PMID 8569290. Unknown parameter |month= ignored (help)
  5. 6.0 6.1 McCauley TR (2003). "Radiation risk of screening CT". AJR Am J Roentgenol. 180 (2): 540–541. PMID 12540469. Unknown parameter |month= ignored (help)
  6. "Radiologyinfo: Safety Radiation Exposure in X-ray Examinations". Retrieved August 30. Unknown parameter |accessyear= ignored (|access-date= suggested) (help); Check date values in: |accessdate= (help)
  7. Prokop M (2005). "Cancer screening with CT: dose controversy". Eur Radiol. 15 Suppl 4: 55–61. PMID 16479648. Unknown parameter |month= ignored (help)
  8. Meyer M. (2002). "Behind the Body Scan Craze". Retrieved August 30. Unknown parameter |month= ignored (help); Unknown parameter |accessyear= ignored (|access-date= suggested) (help); Check date values in: |accessdate= (help)
  9. "Whole-body Scans More Marketing Than Science, Say Medical Physicists. American Institute of Physics". August 26, 2002. Retrieved August 30. Unknown parameter |accessyear= ignored (|access-date= suggested) (help); Check date values in: |accessdate= (help)
  10. Diederich S, Wormanns D. (2004). "Impact of low-dose CT on lung cancer screening". Lung Cancer. 45 suppl 2: 13–19. PMID 15552777. Unknown parameter |month= ignored (help)
  11. Kashiwabara K, Kohshi S. (2006). "Outcome in patients with lung cancer invisible on chest roentgenograms but detected only by helical computed tomography". Respirology. 11 (5): 592–597. PMID 16916332. Unknown parameter |month= ignored (help)
  12. Pickhardt PJ, Choi JR, Hwang I, Butler JA, Puckett ML, Hildebrandt HA, Wong RK, Nugent PA, Mysliwiec PA, Schindler WR. (2003). "Computed tomographic virtual colonoscopy to screen for colorectal neoplasia in asymptomatic adults". New England Journal of Medicine. 349 (23): 2191–2200. PMID 14657426. Unknown parameter |month= ignored (help)
  13. Lauenstein TC, Semelka RC. (2006). "Emerging techniques: Whole-body screening and staging with MRI". J Magn Reson Imaging. 24 (3): 489–498. PMID 16888774. Unknown parameter |month= ignored (help)

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