CT Scans Raise Risk of Brain Cancer In Children

A powerful way to generate precise images of bones and soft tissue inside the body, CT scans, which involve blasting radiation at a person's body to create multi-dimensional X-ray images, have become popular in clinical use. But the amount of radiation they emit is extremely high, and could have devastating consequences years down the road for many people.

For their study, Dr. Mark S. Pearce, Ph.D., and his colleagues compiled data on individuals without a previous cancer diagnosis that had undergone a CT scan within the U.K.'s National Health Service (NHS) between 1985 and 2002. Each patient was younger than 22 years of age at the time, and was definitively determined not to have had a CT scan for any type of cancer diagnosis.

It was discovered that a cumulative dose of roughly 50 milligray units (mGy) of radiation triples a child's risk of developing leukemia, while a 60 mGy dose triples a child's risk of developing brain cancer. Based on the cumulative absolute risk for these cancers, this translates into one additional case of leukemia and one additional case of brain tumor per 10,000 CT scans to the head.

Depending on where a particular scan is directed on the body, CT scans can deliver anywhere from 8.0 mGy of radiation to upwards of 30 mGy of radiation (http://en.wikipedia.org/wiki/Gray_%28unit%29). This means that just one or two CT scans during childhood is enough to significantly increase a child's risk of developing cancer, a significant finding.

"It's well known that radiation can cause cancer but there is an ongoing scientific debate about whether relatively low doses of radiation, like those received from CT scans, do increase cancer risks, and if so the magnitude of those risks," Amy Berrington de Gonzalez of the U.S. National Institutes of Health's (NIH) National Cancer Institute, who also worked on the study, is quoted as saying by MSNBC.com.

"Ours is the first study to provide direct evidence of a link […] and we were also able to quantify that risk."

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Sticking to non-radioactive ultrasound may be preferable to CT scans and excessive X-rays
Between CT scans and X-rays, both of which are used for all sorts of medical analyses and diagnoses these days, cumulative radiation exposure for all individuals is extremely high. Because of this, patients who are told they need such scans may wish to request non-radioactive ultrasound instead.

Though it is reportedly a less accurate scanning method, ultrasound, which of course is used during pregnancy to generate images of a developing baby, often works just fine in place of a CT scan. Magnetic resonance imaging (MRI) is another viable alternative for avoiding radiation exposure.

"Alternative diagnostic procedures that do not involve ionizing radiation exposure, such as ultrasound and MRI might be appropriate in some clinical settings," says Dr. Pearce.

Women who are told to get mammograms should also beware, as this screening method delivers powerful and cumulative doses of radiation that can cause cancer. A viable, non-radioactive alternative to mammograms is thermography