Monday, January 21, 2008

Computed tomography could be a risk to public health?

Computed tomography could be a risk to public health
N Engl J Med 2007;357:2277-84 [Full Text]

Computed tomography (CT) generates ionising radiation, so each scan carries a small but detectable increase in the lifetime risk of cancer. For most people, the diagnostic benefit of a scan outweighs the risk, but at least two experts are getting worried about the effects on the US population of a sharp rise in the use of computed tomography for diagnosis and screening. They estimate that 1-2% of all cancers in the US are attributable to radiation from CT scans [View slide in free full-text BMJ article pdf online].

Children are particularly vulnerable. They are more radiosensitive than adults and have more remaining years of life in which to develop cancer. In the US, 6-11% of scans are performed in children, often to diagnose or rule out appendicitis. Ultrasound might be a better option, say the experts. Other questionable uses of CT, particularly multiple scans, include the investigation of seizures, chronic headaches, or blunt trauma. Using CT defensively is even harder to justify, but not uncommon.

Anecdotal evidence indicates that up to a third of CT scans could be replaced by other diagnostic tests, or not done at all, say the experts. If that is true, about 20 million adults and more than a million children in the US are irradiated unnecessarily each year.

Copyright © 2007 by the BMJ Publishing Group Ltd.

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