A new report in today's New England Journal of Medicine suggests that many people in the U.S. are needlessly exposed to dangerous radiation during medical tests, particularly CT scans. The problem is most clearly evident with respect to children. The report may be overestimating possible risks to adults, but there is a clear reason to think that an excess of these tests pose a public health risk to children.
The study points out that a minimum of 4 million CT scans are done on children per year, with over 62 million done on the American population as a whole. These large numbers are the result of the overwhelming popularity and rapid increase of use of CT scans since they were introduced. These numbers, in conjunction with studies showing that a large percentage of medical tests are completely unnecessary, suggest that many children are being given CT scans when they do not need them.
The risk of CT scans come from the "super X-rays" that the test uses. Children are more susceptible to radiation than adults and more likely to develop cancer because of it. But it is important to remember that the risk to any one particular individual is slight. It is only when we look at large populations that a problem starts to emerge. It is also important to remember that the report is pointing to a potential problem rather than an actual one: the report predicts that CT scans will be tied to a significant percentage of cancer cases. This means that the new report gives us an opportunity to head off a public health problem before it becomes truly dangerous. It also highlights one of the possible downsides of rampant overuse of medical tests.
The New England Journal of Medicine provides the first few lines of the report here: Computed Tomography--An Increasing Source of Radiation Exposure.