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CAT Scans — An Increasing Source of Radiation Exposure

November 29th, 2007 | by David Reiner, M.D. |

                                  

Since the advent of Computed Tomography Scanning(CAT scans or CT scans) in the 1970s, its use has increased tremendously.  It is estimated that 62 million scans are done per year in the US.  Its uses range from diagnosing cancer to evaluating for an infection or pneumonia, assessing amounts of trauma to ruling out things such as blood clots, and most recently imaging arteries to assess for blockages.

By the nature of this technology, it involves the delivery of much larger doses of radiation to the patient than conventional xrays.  The association between radiation exposure and the risk of developing cancer has been increasingly recognized.  This observation dates back to the followup of survivors of the atomic bombs dropped on Japan in 1945.  The risk of developing cancer from this radiation exposure increases with the number of scans a person has, the specific type of CT scanner used, the specific type of exam being done, and the age of the patient.  The younger the patient, the higher the risk because the relative radiation dose is higher in children and their life expectancy is so much longer, therefore there is more time for the radiation effects to become manifested.

The clinical information obtained from CT scanning remains vital to patient care.  However, it is important for physicians and patients to remain as informed as possible about the relative risks and benefits of each study being performed, in order to make reasonable treatment decisions.   Reducing the frequency of scanning as much as possible remains the safest tactic.

Reference: Brenner DJ et al, New England Journal of Medicine Vol. 357, No. 22, 2277-84.

Tags: Computed Tomography, CT scan, Radiation