A New England Journal of Medicine article found that the number of CT Scans most people are exposed to had risen dramatically in the past 27 years. In 1980, doctors ordered an average of 3 million scans per year in the United States. Now, about 62 million CT Scans are done each year in this country. The rise in CT Scans can be attributed, in part, to an increase in `defensive` medicine. This occurs, for example, when people who are admitted to an emergency room are routinely given a CT Scan even before receiving a diagnosis or being seen by doctor. Controversial uses of CT Scans for whole-body scanning, virtual colonoscopy and lung cancer screening have also made CT Scans more prevalent.
The dose of radiation received by patients subject to a CT Scan can be 50 to 100 times larger than that of a traditional x-ray. That is exactly where the problem of CT Scan overuse lies. The type of radiation used in CT Scans, ionizing radiation, has the capacity to damage DNA, causing cells to mutate. This in turn leads to cancer. While the risk of one CT Scan to an individual is small, the study`s authors wrote that they are concerned about the built-up risk of frequent CT Scans over time. In a few decades, as many as 2% of all cancers in the United States might be caused by radiation from CT scans given now.