In 2011, 85 million computed tomography (CT) scans were performed in America, with 11 percent of them performed on children. CT scans combine X-ray and radiation technologies to create cross-sectional views of a person's bones and tissues. This visualization method is most useful in cancer diagnosis, as it can detect tumors and other abnormalities caused by cancer.

But what if the diagnostic method to find cancer was actually causing cancer?

Children are highly susceptible to cancer, if exposed to cancer-causing agents called carcinogens. Carcinogens, which promote an uncontrolled growth of cells in the body and can thus have severe effects in developing children, are found in X-ray radiation used in CT scans.

The use of CT scans in the past ten years has doubled for children under the age of five, and tripled for children between the ages of five and 14.

In a study of radiation doses given to children under 15 years of age from 744 CT scans between 2001 and 2011, new trends in childhood cancer risk are illuminated.

It was found that radiation-induced cancers crop up after scans of the abdomen or pelvis, chest, spine, and brain. The risk of leukemia is highest, as it can occur in the blood and bone marrow, regardless of where the scan is performed. The highest risk scans are those of the abdomen or pelvis and spine with 26 to 34 cases of solid cancers, or tumor development, in these regions for every 10,000 CT scans.

Moreover, the CT scans affect young boys and girls differently. Girls are more likely to develop breast, thyroid, lung cancers, and leukemia, while boys are more likely to develop brain, lung, colon cancers, and leukemia. CT scans account for 68 percent of these cancers in girls exposed and 51 percent of cancers in boys exposed.

The study suggests that about a third of CT scans performed on children are unnecessary. CT scans can also be used to identify bone fractures and internal injuries. However, for instances of identifying non-cancerous ailments, like appendicitis or other sources of pain or inflammation, ultrasound technologies can be used instead and are as effective as, if not more than, CT scans. This could decrease the use of the highest doses of CT administered to children by 25 percent, possibly preventing 62 percent of radiation-related cancers.

Medical technologies can save lives, but their overuse, as has been seen with CT scans in children, can be just as lethal as the diseases they are identifying.

Source: Miglioretti DL, Johnson E, Williams A, et al. The Use of Computed Tomography in Pediatrics and the Associated Radiation Exposure and Estimated Cancer Risk. JAMA. 2013.