Reducing radiation exposure in x-rays for children: the Image Gently program

October 2, 2010  |  General

I’ve been doing this blog for three years, and by far the post that has provoked the most interest is this one, about the safety of x-rays. The comments, now at 102, keep steadily coming. Google tells me that the most common search string that brings folks here is some variant of the question: “how safe are x-rays?” Recent studies, such as this one, have highlighted the issue of CT scans.

The important thing to understand is that nobody wants to stop doing x-rays and CT scans. The latter in particular represent a quantum leap in our diagnostic ability, and appropriate x-ray studies improve and even save children’s lives. What we want is to strike a balance between doing too few and too many. The question always to consider is this: what is the risk of doing the x-ray or CT (still very, very tiny) versus the risk of not doing the study, of not getting the information the study provides. If the study is needed to rule out the possibility of a serious condition, then the risk/benefit calculation virtually always favors doing the test.

There is another consideration, one highlighted recently by the Alliance for Radiation Safety in Pediatric Imaging, an initiative led by pediatric radiologists — the Image Gently initiative. The concept is simple: use only as much radiation as you need to get a good picture. In the past, CT scanners in particular often used radiation doses more appropriate for adults than children. Using that dose causes risk without adding benefit.

If my child needed a CT scan, I would ask the doctor to lay out the risk/benefit ratio — the risk of doing versus not doing the scan. If the scan is needed, I’d then ask if the radiologist will use the minimum dose required to get a good picture.

This site, from the International Atomic Energy Agency, has lots of useful information about protecting patients from unnecessary radiation.

Here’s a useful short post by a pediatric radiologist about all this.

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12 Comments


  1. What about VCUG’s? My infant has had one and my oldest daughter has had 2 (with more to come) to check for outgrowing of vesicoureteral reflux. In addition to her having a chest xray, an abdominal xray, and an forearm xray, these plus the VCUGs keep me up worrying every night of my life. I know they are necessary, but it doesn’t help my worry!! It is a relief to read they are safe, but I can’t help worrying that there is some information that we don’t know of out there. I want to trust the people that tell me they are safe and I can stop worrying! Thanks so much :)

  2. Hi Jade:

    Yes, VCUGs carry even more radiation than do simple x-rays. The key, I think, is if a doctor wants another VCUG to ask the doctor if the information is really needed at this point. For example, could a kidney ultrasound give the same information?

    As with everything in medicine, the calculation is always balancing the risk of a test or procedure against benefit. The presence (and severity) of urine reflux from the bladder up to the kidney is important to know about — it can have a major impact on a child’s future. But, once we know about it, how many VCUGs do we need to follow it? I’m not an expert in the kidney, but that is a subject of some debate.

    Again, if it were my child, I’d be pretty brutally direct in quizzing the doctor as to why each VCUG is needed. Make them convince you.

    I understand why you worry about it. But, as I’ve said before, we do many things with our children of much higher risk than x-rays without even thinking about it — driving on the highway, for example.

  3. Jade, you are not alone. I worry too about my child’s xrays.

    Chris, I was wondering which test is riskier in terms of radiation to an infant: 2 view chest xray, skull xrays, upper gi, or hip xrays?
    Thanks so much for all of you help and your blog!!!

  4. Hi Julie:

    All of those are far less than a CT scan, but I believe of those on your list the upper GI series would have the most radiation, followed by the skull series, then the hip, then the chest x-ray. But because the radiation of each of these is pretty low in comparison with the CT, I wouldn’t really describe one of them as significantly “riskier” than the others.

  5. Thanks Chris. I am still upset with myself for going through with the skull xrays on my infant son. The radiology center said he got .03msv. I need to stop worrying.

  6. I just looked on xrayrisk.com and it said skull and chest xrays are .1 msv, and hip xrays unilateral are .7msv. does this mean skull and chest have the same and then hip has 7 times more radiation? Thanks.

    Also, are there elderly people living who have had skull xrays done as an infant and suffered no harm from them?

    Thanks for your time, Chris.

  7. Hi Julie:

    Yes, that would mean the hip films have 7 times the radiation of skull and hip films. But those 2 numbers — 0.03 msv and 0.1 msv — are pretty different: one is 3 times the other. Perhaps the higher number was with older equipment?

    The way to think of it, though, is that 7 times a very low number is still a very low number. What we need to know is what the biological difference between 0.1 msv and 0.7 msv is — my guess is that not much. The problem is that cell biologists, as far as I know, haven’t established the threshold dose for increased cancer risk over a lifetime. Most of the data we have is extrapolated down from very high exposures, such as Chernobyl and WW II.

    That doesn’t mean we should not concern ourselves with the risk, of course. My own daughter had 50-60 chest x-rays as an infant, and I do wonder about it from time to time. But, as I keep saying, we need to balance the risk of the x-ray against the risk of not having the information the x-ray gives us. I know my daughter needed those films at the time in order to decide what to do, and the choices then were significant.

    So, to answer your question, there are thousands upon thousands of older folks who have had skull films as an infant and suffered no harm from them.

    CT scans are another matter. I did a post about that last year here:

    http://www.chrisjohnsonmd.com/2010/04/03/ct-scans-and-cancer-thinking-about-the-meaning-of-risk/

  8. Thank you!!!

  9. I really appreciate this article. My 4-month old son just had a VCUG to look for reflux in the kidneys or a blockage. He had already had a kidney ultrasound. He had it done at a Children’s Hospital near where we live. They took an abdominal x-ray before hand, in which they did not shield his gonads, and then did the VCUG, also with no shield. I was very concerned about radiation exposure, and they told me the total dose was .570mGy, and the fluorotime was .2 min. I am very concerned about the degree to which this level of radiation exposure would cause later fertility problems or increase his cancer risk, particularl in light of his young age. I really really appreciate any information you can give. Thank you!

  10. Hi Courtney:

    Yes, the VCUG study does involve some radiation, and the risk of that, while very, very, very small, is not zero. I think what you need to keep in mind, though, is how doctors approach the issue: the key point is if the very tiny risk of the radiation is higher than the risk of not getting the information that the VCUG gives. It’s important to know if the kidneys are working well and that there is no obstruction or reflux of urine back up into the kidneys, and the VCUG is the only good way we have now of telling if that is the case. No there is risk to your child’s health in not having that information.

    Everything in medicine boils down to relative risk — the risk of doing one thing, in your case the test, balanced against the risk of not doing whatever it is. Nothing is risk-free. You need to decide which is the best risk to take. I think you made the right choice in this situation.

    Put another way, the risk to your child of driving to get the VCUG, of getting in a serious car accident, is actually higher than the risk from the radiation from the test. Yet we drive all over the place with our children without thinking about it because we’re used to it.

    Thanks for stopping by.

  11. Thanks so much for this information! I commented back and June… I have since learned of a study done by Berkeley that says only 1-3 simple xrays (not CT’s) increase a child’s risk of Leukemia (ALL). What do you make of this? HOW much of a risk? A significant risk? Probaby not the study I should’ve read with my already present anxiety on this issue. It does not say how significant of a risk from what I read, but with two young children and multiple xrays each, I am freaked out now more than ever. Before, it looked like the research didn’t show much, but this study is scaring me! I believe it was done in October of 2010. Your comments on this research would be greatly appreciated. My daughter has had Deflux and a VCUG is scheduled for July (her 3rd one) to check and see if it worked…I wish there was an alternative. Ultrasounds of her kidneys have always been normal, but reflux was still present, so they kept telling me there was no other way. I was so scared!! Also, we live at sea level and have not had to fly with our children on a plane. Does this cancel out some of the radiation risk from the medical xrays they have received? Thanks so much…I am truly sick about this study and what it means for our children. My child’s pediatrician always says its just fine and she would be a mutant by now if xrays did anything to her as a child. Dismisses all of my concerns…

  12. My daughter had an abdominal CT scan done when she was 16 and then a CT head scan at 17. Of course, I am very concerned and have a lot of anxiety about all of the radiation exposure to her. I recently read that abdominal CT scans in girls can effect their eggs and cause problems for their future children. Do you believe this is true?