Continuing Promise 2011

CT scans increase risk of childhood cancer

Dr. Lisa Dana

posted: June 7, 2012, 8:55 am

in: Health & Safety, News, Mom Stories

New research published today in the Lancet shows that children who receive multiple CT scans in childhood are at increased risk of developing brain cancers and leukemia.

The cumulative radiation from CT scans is measured in mGy (milligrays.) A milligray is a unit of absorbed radiation. The research, led by Dr. Pearce, found that cumulative doses of about 50 mGy may triple the risk of leukemia and doses of about 60 mGy may triple the risk of brain cancer.

CT scans were first introduced in the 1970’s. CT scans are often used to diagnose head and neck injuries in children. According to CBSNews, the number of kids who were given CT scans in an emergency room visit increased five-fold between 1995 and 2008.

The researchers did emphasize that these cancers are still very rare. In their research they found that “one excess case of leukaemia and one excess case of brain tumour per 10 000 head CT scans is estimated to occur.”

CT scans can be very helpful, and important in the diagnosis and care of a patient. The fear from this research, is that parents will refuse a CT scan for their chid because of this risk of developing cancer. As physicians, we always try to evaluate the risk and benefits of any treatment or procedure prescribed for a patient. CT scans are still necessary as a means of diagnosing certain illnesses or injuries. It is important that clinicians be aware of the radiation risks as they consider evaluation and treatment of their young patients.


Sources: The Lancet, CBSNews

Photo:Flickr/Official U.S.Navy Imagery

Dr. Lisa Dana


Read Lisa's full bio
  • JK+2

    Maybe I’m being too logical, but was this study really needed?? We all know that radiation can cause cancer, so we should assume that getting a CT could in turn increase our risk of cancer. I would hope that no doctor would order a CT scan unless they felt strongly that it was needed. And I would hope that a parent wouldn’t refuse one that a doctor felt was really needed just because there is a very very small chance of cancer later on. I just think this was wasted time, energy, and money on something that is kind of a “Duh!” in my book.

  • Julius

    I am curious about the use of CT scans vs. MRIs. I know MRI is much more expensive and longer procedure.

  • Twigger70

    Hasn’t this news been out for years? There was evidence, I believe, that numerous CT scans could cause a higher rate of cancer in adults…so what’s news about the same being true for children? My son had one at 2 months old to rule out craniosynostosis (sp?)–again, a correct diagnosis of what’s wrong is often worth the slight bit of heightened risk, IMO.

  • Jen E.

    @ Julius, MRIs do not use radiation, so the risk would be zero. CT and MRI are not necessarily interchangeable though, which test to use depends on the clinical situation. And because MRIs take much longer and require the patient to lie extremely still, it is much more likely that a child would need to be sedated to undergo an MRI.

    If it is an option, parents may want to use a facility that is used to imaging children. There are techniques that can be used to reduce the CT radiation dose when scanning children, but some centers that typically scan adult patients may not have any pediatric protocols in place. Feel free to ask them.

  • Carla

    Interesting to see this. I recently had a CT scan and was actually told this, that there is an increased cancer risk in children. But with respect to why bother study it, I was also told that there was no increased risk in adults from head CT scans. If they already knew that, and just assumed that it would be the same in children, we wouldn’t have known this. Yes, there’s common sense, but ‘common sense’ doesn’t always line up with the facts.

  • julius

    Thanks Jen E. You provided a lof of helpful information.

  • CT Tech

    To JK+2…..yes you would like to think that Doctors would only order something like a CT scan if it was TRULY necessary but the reality is that with the rise in malpractice suits against doctors in recent years most ER doctors are “OVER ORDERING” procedures like CT just to cover their own butts! They don’t want to be sued so they over compensate just to satisfy the patients (or the parents of a patient) that they did everything. I know this because I am a CT/MRI technician at a busy hospital and I can’t tell you how many times I scan children for no other reason than to satisfy the parent or the patient that is just convinced that something is wrong with them. Alot of times the doc orders the CT just to prove to the patient that NOTHING is wrong with them. Totally unnecessary! This is why insurance companies are starting to refuse to pay for excessive radiology tests because they are becoming wise to what is acutally going on in the healthcare field!

  • Beth

    Im an ED nurse and you would not believe the amount of parents that insist on a CT scan for the smallest injury. The doctors I work with always explain the risk of cancer, but with the Internet it seems most parents think they know more than the people with medical degrees!

  • Amber

    @JenE – There are risks with sedation, not cancer risk (which is probably what you meant). Anesthesia for the very young has been linked to learning problems, however.

  • http://Whilethelittleonessleep.wordpress.com Anjali

    My daughter was sent for a C.T. Scan at three months of age after a skull x-ray because the doctor thought her head measurement wasn’t following the curve. After she had the C.T. Scan, the technician measured her skull. Something made me ask for the measurements. Turns out it was completely different from the one taken at the doctor’s office. My totally normal daughter was subjected to huge amounts of radiation because of sheer carelessness. Neither my husband nor I will ever be able to forget the stress we went through.



  • http://zodapops.blogspot.com Krissy

    I already knew all this, and though it is good to keep in mind, when parents are faced with possible bleeding on the brain vs. possible tiny increase of cancer in the future I’m sure parents will still choose to go through with the scan. We did.

  • Adub

    These ‘studies’ are so pathetic. It makes me wonder who is paying for them and why they reach the public or professionals for that matter. Going to the beach, living in Denver or any high altitude, …stepping outside increases your radiation dosage over your lifetime. And yes it’s the same radiation. And yes we know it leads to cancer and there are theories on why. However, most children do not get CT scans unless something is seriously wrong, and most kids that have had a CT scan do not get cancer. Could it possibly be the reason they were getting the CT scan in the first place had something to do with their increased risk? Why correlation=causation became the truth of the day will frustrate me till I die!

  • Jessica

    @JK+2 – As of 7 years ago (when I left school) the ‘recommended maximum safe radiation’ was really only a guess. Everyone has known for years that radiation is dangerous, but some amount of radiation is safe. From a medical point of view, this study is important because it gives a solid measurement of when radiation starts to become dangerous. And that is in addition to what CT tech said about malpractice suits, which really are getting out of control and leading to a lot of unnecessary tests and procedures.

    Personally, given how rare those cancers are, and that radiation over 50mGr only increases them by 1 in 10,000, I don’t find this study worrying, and would have no problem with my children having needed CT scans.

  • AC

    According to the FDA, the radiation in ONE CT scan to the head is about equal to the radiation used in ONE HUNDRED chest x-rays.


  • Cvoy

    My son was diagnosed with Hydrocephalus at the age of 6 weeks. The size of his head was out of proportion due to cerebral fluid which was building up and not passing quickly enough from the brain out to the rest of the body. He had to undergo a head ultra sound and a CT scan finally to confirm the diagnosis of Hydrocephalus. He then had to undergo a surgery to have a shunt put in place in his head to correct the flow of cerebral fluid. Up until he was 2 he had to have two more brain surgeries because of shunt failure. Which can only be determined with an MRI and another CT scan. In our case, the CT scans saved his life. We do have to live with a certain amount of fear of cancer but when faced with certain medical scenarios that’s part of it. Today he is doing remarkable, he’s a 10 year old boy and a top pitcher in his Little League..but…as anyone who is familiar with Hydrocephalus knows…at any time his shunt could become clogged or malfunction and he could be in the emergency room possibly needing a CT scan. Sometimes it comes with the territory. I do appreciate these studies because to me, it means the medical community is constantly evaluating and conducting research on what exists out there and giving us #s on the amount of radiation that could cause cancer. It’s not enough to just be told “it could cause cancer” you need to know the details, odds of it occuring, that over over 50mGr is dangerous etc. The more you know the better you can deal with a medical situation if faced with it. I say, keep up the research and the studies, you need it, if your up against some tough circumstances.

  • http://BabyCenter Victoria

    Please learn to read scientific studies carefully. ALWAYS look for word like “may”, or “might” or “could”….that tells you it is a theory of someone who “thinks” they see a correlation between a procedure, medical or otherwise and a disease. Take these studies with a grain of salt. Think ALWAYS about that before you panic. If you look at the original statement you will see the word “may” in this case. We learned this critical thinking in medical statistics in college. A good course to help you throughout life to consider the truth vs theory.

  • Charlie

    My son had a CT scan at three months old. we were pretty much forced to choose between that and a MRI we really did not want either one we had brought him in because he had thrown up so bad I thought he was in need of medical care. But the moment they found out that his doctor was wanting to do an ultra sound on his brain to check for fluid they began running all kinds of tests. My poor baby went 14 hours with out any breast milk or even an IV. They told us that is they did an MRI they would have to put him under and there was a chance that he could die from the medication and they may not be able to save him. so we had to do a ct scan or they were not going to let us take our baby home, if he ends up with Cancer and we find out that is the reason, I will take them to court.

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