By Huy Nguyen

For over a decade, scientists have suggested that radiation from childhood CT (computed tomography) scans may increase the risk for cancer later in life, based on the estimated radiation exposure of survivors of the atomic bombs in Japan. Today, researchers funded by the National Cancer Institute published important new results in the journal Lancet.

This study followed 178,604 British patients who received CT scans when they were younger than 22 years old and showed a dose-dependent increased risk of brain cancer and leukemia. Their results suggest that children younger than 15 years old who receive 2-3 head CTs, could have almost triple the risk of brain tumors later in life; 5-10 head CTs could triple the risk of developing certain types of leukemia.

So should your child receive a CT scan recommended by your doctor? It is important to put these new data into perspective.

Because the risk of your child developing brain cancer or leukemia is very small, doubling or even tripling it still results in a very small absolute or actual risk of cancer. If your doctor recommends that a CT scan is the best way to evaluate your child’s illness, the benefits to your child’s health most likely far outweigh the additional cancer risk posed by the CT scan. Nevertheless, parents should feel comfortable asking their child’s doctor about why a CT scan, as opposed to other imaging options, is justified.

This study, though, highlights the need to consider the safety of this increasingly available imaging technology.

For more information on how you can help to minimize the risk for your child, see the FDA’s recommendations and Image Gently, a campaign by the Alliance for Radiation Safety in Pediatric Imaging.

Dr. Nguyen is Boston’s medical director. Read more about him here.