Radiation Risk and CT (CAT) Scanning

On November 29, 2007 a review article titled "Computed Tomography - An Increasing Source of Radiation Exposure," authored by David Brenner, Ph.D., D.Sc., and Eric J. Hall, D.Phil., D.Sc., was published in the New England Journal of Medicine discussing the risk of radiation from CT (CAT) scanning. The article is accurate, and put into proper context, reminds all of us of the risk of radiation and the need for judicious use of any x-ray procedure. There are several points that should be emphasized when looking at the risk of radiation, particularly when referring to CT (CAT) scanning as was examined in this editorial.

• CT helps save lives – in many cases it is the imaging exam to use to provide the best possible care to a patient. Thus, diagnosis with x-ray or CT (CAT) should not be delayed or deferred due to a fear of radiation.
• The best way to decrease radiation exposure is to not perform unnecessary examinations. No radiographic examination should be performed if the benefit of performing the scan is less than the risk.
• The lowest possible dose that produces diagnostic images should be used.
• Current radiation doses on new scanners are less than described in the article. All new scanners have x-ray dose modulation functions, which significantly reduce the dose to the patient.
• All radiologic examinations should be performed in consultation with a physician.
• In children especially, as they are more sensitive to radiation, other modalities not involving radiation such as ultrasound or MRI, should be considered.
• This editorial is about risk to the entire population, not to an individual. The risk of radiation from any single examination to one patient is quite small.
• The American College of Radiology (ACR) produces the ACR Appropriateness Criteria, which are evidence-based guidelines to assist your physician and other providers in making the most appropriate imaging or treatment decision. These criteria report relative radiation levels of each type of exam.

If you wish to read the article yourself, you will find it at: http://content.nejm.org/. There is no charge. The reference is: N Engl J Med 2007;357:2277-84.

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