A study published Wednesday in Lancet warns about the increased cancer risk in children who have two or three CT scans, and scary news reports about it may have left some parents in a panic. After all, a lot of kids have had more than one CT scan, after an appendicitis attack, car accident, or severe head injury.

Yet parents should understand that even though the study found that repeat CT scans were associated with a tripling in risk for both leukemia and brain cancer, the absolute risks of these two rare cancers still remain very small. Brain tumors occur in 3 out of every 100,000 children each year, while leukemia occurs in about 4 out of every 100,000 children, according to the National Cancer Institute. Thus, a tripling in risk would increase a childs yearly chances of developing a brain tumor to 9 in 100,000 and of developing leukemia to 12 in 100,000.

That doesnt mean, though, that doctors should order CT scans willy nilly without regard for the radiation risks -- even one CT scan delivers a hefty dose of radiation, many times what youd get from an X-ray, that lingers in the body, perhaps for a lifetime.