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Full-body CT scan

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Full-body scan is a scan of the patient's entire body to support the diagnosis and treatment of illnesses. It may also be known as a full-body CT scan if computed tomography (CAT) technology is used, though there are many types of medical imaging technology which can perform full-body scans (see box on bottom of page).

History

CT scans were first used in medicine in the 1970s,[1] and they now play an important role in diagnosis in medicine.

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Overview

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Use in preventative screening

Full body PET scan.

A full-body scan can theoretically catch deadly diseases (e.g. cancer) in early stages, which can save lives. However, there 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], because the risks may or may not outweight the benefits. As with any test that screens for disease, the risks of full-body CT scans need to be weighed against the benefit of identifying a treatable disease at an early stage.[3]

Tradoffs

Health risks

  • Depending on the technology used, there may be relatively high doses of radiation with a full body scan[4]. This is not an issue with MRI, which produces no radiation. Conventional CT scanners (e.g. PET) may expose patients to 10 mSv (see ionizing radiation),[5]. Obviously the health risks depend on the technology used (see CAT scan, PET scan, MRI scan, etc.).

Other issues

  • Low rate of finding disease.[6][7]
  • Benign abnormalities:[6][7] These may not be related to any disease, and may be benign growths, scar tissue, or the remnants of previous infections. CT scanning for other reasons sometimes identifies these "incidentalomas", and it is uncertain how to treat some of them, or if treatment is necessary.[8]
  • Possibly high cost: At a cost of US$600 to $3000 full-body scans are expensive, and are rarely covered by insurance.[9][10] However, in December 2007, the IRS stated that full-body scans qualify as deductible medical expenses, without a doctor's referral. This will likely lead employer-sponsored, flexible-spending plans to make the cost of the scans eligible for reimbursement.[11]

Alternatives

Not having full-body scan

According to the U.S. Dept of Health and Human Services (including the Federal Food & Drug Administration), the use of whole-body scanning has not been shown to detect disease earlier or extend life of a healthy, symptomless person, than a physical exam and traditional screening tests.[12]

Partial-body 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.[13][14] 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; however the initial diagnosis is significantly less invasive.[15]

Other types of scans include Heart, Brain, Bone density, Angiogram, Carotid artery.[16][17]

Magnetic resonance imaging (MRI) scans are associated with a lesser radiation risk than CT scans, and are being evaluated for their use in screening.[18]

  • In the episode "Role Model" of the TV show House the lead character Dr. Gregory House refers to full-body scans as "useless" because, in his words, "you could probably scan every one of us and find fifty doo-dads that look like tumors".

See also

References

  1. ^ Hounsfield GN. (1976). "Historical notes on computerized axial tomography". J Can Assoc Radiol. 27 (3): 135–142. PMID 789383. {{cite journal}}: Unknown parameter |month= ignored (help)
  2. ^ "U.S Food and Drug Administration Whole body CT scans, DHHS Publication No: (FDA) 03-0001". 2003. Retrieved August 30, 2006. {{cite web}}: Unknown parameter |month= ignored (help)
  3. ^ MacLean CD (1996). "Principles of cancer screening". Med Clin North Am. 80 (1): 1–14. doi:10.1016/S0025-7125(05)70423-5. PMID 8569290. {{cite journal}}: Unknown parameter |month= ignored (help)
  4. ^ McCauley TR (2003). "Radiation risk of screening CT". AJR Am J Roentgenol. 180 (2): 540–541. PMID 12540469. {{cite journal}}: Unknown parameter |month= ignored (help)
  5. ^ "Radiologyinfo: Safety Radiation Exposure in X-ray Examinations". Retrieved August 30, 2006. {{cite web}}: Cite has empty unknown parameter: |month= (help)
  6. ^ a b Brant-Zawadzki MN (2005). "The role of computed tomography in screening for cancer". Eur Radiol. 15 Suppl 4: 52–54. PMID 16479647. {{cite journal}}: Unknown parameter |month= ignored (help)
  7. ^ a b 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. {{cite journal}}: Unknown parameter |month= ignored (help)
  8. ^ Grumbach MM, Biller BM, Braunstein GD, Campbell KK, Carney JA, Godley PA, Harris EL, Lee JK, Oertel YC, Posner MC, Schlechte JA, Wieand HS (2003). "Management of the clinically inapparent adrenal mass ("incidentaloma")". Ann Intern Med. 138 (5): 424–429. PMID 12614096. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  9. ^ Meyer M. (2002). "Behind the Body Scan Craze". Retrieved August 30, 2006. {{cite web}}: Unknown parameter |month= ignored (help)
  10. ^ "Whole-body Scans More Marketing Than Science, Say Medical Physicists. American Institute of Physics". 2002-08-26. Retrieved August 30, 2006.
  11. ^ "Diagnosis? It's Deductible".
  12. ^ http://www.fda.gov/cdrh/ct/screening.html
  13. ^ Diederich S, Wormanns D. (2004). "Impact of low-dose CT on lung cancer screening". Lung Cancer. 45 suppl 2: 13–19. doi:10.1016/j.lungcan.2004.07.997. PMID 15552777. {{cite journal}}: Unknown parameter |month= ignored (help)
  14. ^ 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. doi:10.1111/j.1440-1843.2006.00903.x. PMID 16916332. {{cite journal}}: Unknown parameter |month= ignored (help)
  15. ^ 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. doi:10.1056/NEJMoa031618. PMID 14657426. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  16. ^ http://www.scandirectory.com/content/faq.asp#faq10
  17. ^ http://www.scandirectory.com/news/news_details.asp?ID=67
  18. ^ Lauenstein TC, Semelka RC. (2006). "Emerging techniques: Whole-body screening and staging with MRI". J Magn Reson Imaging. 24 (3): 489–498. doi:10.1002/jmri.20666. PMID 16888774. {{cite journal}}: Unknown parameter |month= ignored (help)
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