FDA Says CT Scans Need To Be Safer

Acting to make the administration of CT scans safer, the Food and Drug Administration released documents that urged better training for those who administer tests as well as warnings for patients about the radiation levels to which the tests expose them.

The New York Times reports the FDA reached its findings after a yearlong study of radiation poisoning in stroke patients who underwent the same CT tests.

If you’ve had CT scans done, has the radiation affected you?

F.D.A. Urges Two Steps for Safer CT Scans [The New York Times]


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  1. nucwin83 says:

    I have had a head CT done, but according to the almighty Wikipedia, that’s only about 15 chest X-rays, and still within what I’d get from normal background radiation over a year. I’d think as long as you weren’t going through CT scans on a regular basis, there’s really not much to worry about. Of course, that could be the radiation talking.

    • jessjj347 says:

      Also according to Wiki: “Although CT scans come with an additional risk of cancer (it can be estimated that the radiation exposure from a full body scan is the same as standing 2.4 km away from the WWII atomic bomb blasts in Japan[24][25]), especially in children, the benefits that stem from their use outweighs the risk in many cases.[22] “

      I found the comparison to proximity to an atomic bomb interesting.

    • JiminyChristmas says:

      The issue raised by the NYT investigation was that mis-calibrated or misused CT scanners were giving patients radiation overdoses in the course of the scan. A more apt comparison than to the dose of a chest x-ray would be comparing a head CT to skull x-ray. One head CT equals about 200 skull x-rays. The worst-affected patients identified in the NYT article were getting 13x the correct dose of radiation. In other words: 2600 skull x-rays.

  2. WiglyWorm must cease and decist says:

    There is a study out there that estimates as many as 1 in 50 future cancers will be caused by CT scan radiation. That is a HUGE number.

    If a doctor suggests a CT scan, ask about an MRI instead. They used to take a long time (up to an hour), but if you’re in a modern facility with a 64-slice (or greater) MRI machine, it only takes minutes to get a complete scan, and it’s radiation free.

    Quite honestly, MRI scans are BETTER for diagnosis, anyway. Hospitals prefer CT scans, though, because they are very high profit margin.

    (Disclosure: I work for a community hospital in the IT department)

    • shotgun_shenanigans says:

      However, sometimes an MRI is not possible for a patient. If someone (like my father) has metal screws or plates or anything, can’t do an MRI. I don’t know if a MRI will mess with the iron oxide in tattoos, so they may or may not be able to get one. Also, in a trauma scenario like an ER, when time is of the essence and the doctors don’t KNOW if the person they’re sending through has any metal plates, they’ll do a CT.

      So CT scans are still necessary. Which is probably why the FDA is trying to make them safer. Getting it once in your life isn’t going to kill you, but if you have a condition that requires a few CT scans, it may become a concern.

      • shotgun_shenanigans says:
        • WiglyWorm must cease and decist says:

          If you’re referring to the “motion artifact”, modern MRI machines with 64 or 128 slices will capture the whole heart between beats. It’s not as much of an issue as it used to be.

          • shotgun_shenanigans says:

            As far as diagnosis goes, yes the new 64- and 128- slice MRI machines have vastly reduced motion artifact, which makes them more useful.

            However, those 64/128’s are not as widely available as CT’s are, and like I said, CT’s are still preferred in an emergency situation.

            I’m not trying to set up a false dichotomy or anything. There’s no reason a hospital can’t have both, and many of them do. I’m just saying they each have their uses, and CT’s are gonna be around until something else comes along that can do EVERYTHING they do, but better.

            • darcmosch says:

              If anyone is a fan of Mythbusters, you would know there is 0% chance of your tattoo being ripped out from an MRI unless you’re tattoo is like 100% of a ferrous metal.

            • darcmosch says:

              If anyone is a fan of Mythbusters, you would know there is 0% chance of your tattoo being ripped out from an MRI unless you’re tattoo is like 100% of a ferrous metal.

      • csobolewski says:

        I just went and asked the head of radiation informatics (and a former army radiologist). You can indeed get MRIs when you have tattoos. He actually just got one, and he has a huge tattoo.

        That said, yes there are still plenty of times when a CT is necessary (most specifically in a trauma situation where you don’t have time to perform an xray to make sure there is no forgien metal, etc.), I just wanted to be sure to let people know that ESPECIALLY when it is a planned procedure, there’s a good chance that profit is the driving concern behind the choice of test.

        • borgia says:

          Its depends on the pigments used in the tatoos. Some pigments have metal in them but, even then, you can still have an MRI. You may feel a burning or itching on the tatooed skin

      • borgia says:

        It is possible to have an MRI with non ferro magnetic metal screws and plates. Titanium parts are usually the best because they provide less interference. If the metal parts are too close to the part being scanned there may be too much interference in the signal. Also there are restrictions on how recently the metal part has been implanted. It has to have been there long enough for the bone to Osseointegrate.

      • GinaLouise says:

        I had brain and spinal MRIs while I had a mouthful of braces. It was perfectly safe, although the metal did cause artifacts on the scan of my spinal cord (just the part behind my braces). As long as the metal isn’t loose, you’re home-free.

  3. Endless Mike says:

    Yes. I gained the proportional strength and agility of a CT scanner operator.

  4. Applekid ┬──┬ ノ( ゜-゜ノ) says:

    Ever since I got my CT scan, I cry every time I see a tree.

    I sort of attribute that to the meth, though.

  5. Mike says:

    You know I heard some of the scary statistics about CT scans…two days after I had my first one. I guess I should have known that it was dangerous from the way the technicians dove into what looked like a bomb shelter after they strapped me into the machine and turned it on.

    • nucwin83 says:

      And yet the CT scanner *sounds* a lot less deadly than an MRI’s *CLUNK CLUNK CLUNK CLUNK* sound right around your head. Heh.

    • crashfrog says:

      To be fair – you’re there to get a single CT. He’s working next to the machine all day long, scan after scan, for years. You bet he’s going to try to minimize his radiation exposure per scan. You? It’s not so important.

      That’s why your dentist leaves the room for your dental x-rays, but you just get a lead vest. He’s got a whole lifetime of exposure to worry about; you’re just there for one x-ray.

  6. Julia789 says:

    As long as they are calibrated properly, the risk is low. There were recent cases where the machines were grossly mis-calibrated, and patients received very high doses. However, that was one machine out of thousands.

    There was another case last year where a small child received hundreds of times the normal dose becaues a terribly incompetent and cruel technician repeated the scan dozens of times claiming she could not get a good picture. The parent protested and another technician was called in, and got a good picture in one try, in just a couple of minutes.

    The child is sure to get cancer at some point, said doctors who evaluated the dose he received. However, the parents can’t sue until he actually gets cancer… The technician has been fired.

    • mythago says:

      And when the kid does sue, the hospital will argue that his lawsuit should have been filed years ago when he knew he was at risk.

      • Julia789 says:

        Yeah I remember reading a legal forum where law students were discussing the problems with that poor child’s case. If I recall correctly, he can’t really sue unless he can “prove” harm was done. The effects of radiation may, or may not, cause future cancers and other problems. You can’t sue for something that “might” happen. (Any lawyers out there please help me to understand this correctly. I’m probably butchering it.)

        By the time the kid gets cancer or other medical issues from the radiation, it might be too late to sue, from what I understand? I am sure the family is working with an attorney to do all that can legally be done.

        All lawsuit talk aside, the poor kid could die a slow horrible death from cancer. The poor toddler – I feel so bad for him, and for his parents. As a parent, I got tears in my eyes reading that article.

    • Julia789 says:

      Here is the NYT article on those CT overdoses – it has the details I was a little fuzzy on:


    • Nigerian prince looking for business partner says:

      “As long as they are calibrated properly, the risk is low. “

      I think that’s the problem. If I were to need a CT scan, I’d go wherever the nearest in-network facility. Even if a comparison between facilities was possible, I’d still by limited by insurance.

  7. minjche says:

    I’ve had 9 CT scans of my head from some head trauma when I was a kid.

    So far no issues that I know of, but I’m only in my 20’s.

    • Julia789 says:

      I had a couple CT scans when I fell on concrete as a kid, and was knocked unconcious, and another after a car accident that knocked me out for an hour.

      I do worry about radiation, but the benefits of doctors knowing if I was bleeding into my brain outweighed the risks. :-)

      • minjche says:

        Yeah I have metal plates on my skull from when I got smacked in the head by a baseball bat, and the CT scans were to check that my skull wasn’t growing over the metal plates (and possibly being moved inward toward my brain).

        But hey! On the plus side, now I have a sweet scar and a great conversation piece.

  8. Dover says:

    From what I understand, a good part of this is attributable to design deficiencies; the equipment did not do enough to warn the technicians that they were pumping up the radiation levels too much.

    /Human factors engineer
    //Wife had CT scan at Huntsville Hospital
    ///Make my own excessive radiation at home

    • flickchickca says:

      If the technologists were properly trained, they wouldn’t need the machine to warn them they were overexposing patients. I truly believe this was human error, and not machine error.

    • jessjj347 says:

      Also, I’ve read studies where medical professionals ignore safety alerts or overwhelmingly override them. Basically, my thought is that either :
      1) receiving a false alert lowers the users’ trust in the alerts (also I could imagine a boy who cried wolf mentality)
      2) receiving too many alerts could make them seem less pressing or important, thus people ignore or override them

  9. Blueskylaw says:

    “If you’ve had CT scans done, has the radiation affected you?”

    I don’t know, I need a test to determine that.

  10. Blueskylaw says:

    “If you’ve had CT scans done, has the radiation affected you?”

    I don’t know, I need a test to determine that.

  11. osiris73 says:

    They did a CT of my ankle after a severe sprain, looking for torn ligaments, muscles etc. and I tell ya what… it hurt like a bitch. I’ve had CTs of other areas and they were completely painless. This one was excruciating. I mentioned this to my physical therapist who had a bit of a far away look and said, “Huh, you know, you’re the second person this week to tell me that.”

    • erciesielski says:

      Did you have any of that contrast dye injected? I don’t understand how the xray itself can be painful.

      • osiris73 says:

        I did not have any dye injected. Frankly, I couldn’t understand how it was painful either, yet it was. Very much so. And it wasn’t just the position my ankle was in during the procedure. The pain was only present when the machine was running. They started and stopped it several times and each time the pain ceased within seconds of the machine stopping.

        • crashfrog says:

          Oh, wow. If you can feel anything at all, you’re getting way too much radiation from the scan.

          Jesus. Well, as a consolation prize, you may be the first person I’ve ever heard of to develop ankle cancer.

    • mamacat49 says:

      I think you had an MRI–not a CT. Patients get them confused all of the time.

  12. Omali says:

    I had several CT scans this year…thanks.

  13. flickchickca says:

    I’m a radiological technologist (the person who takes x-rays and CT scans). I live in Canada, and I see a HUGE difference between radiation exposure here and in the States.

    In Canada, it takes four years of university to become a rad tech, plus you must write a certifying exam. I believe in most states, you can become a rad tech with only two years of college. We also have more safeguards in place to protect the patients. Our machines are tested more often, and patient doses are calculated and sent to the radiologists with every CT scan.

    Something else to be aware of is that many doctors practice cover-your-ass medicine. So they’ll order a CT scan just to be 100% sure, even when they’re pretty sure you’re fine. This makes it worth talking over with your doctor when they order a CT whether it really is necessary or not.

  14. Kibit says:

    My husband had a CT scan to determine if he had a Kidney Stone, he did. The second time they did an xray. This whole article makes me nervous. Arg!

  15. woolygator says:

    Not that I know of and I get CT scans a lot. I’m a transplant patient.

  16. Mulysa says:

    I have been getting CT scans every 6 months or so after they embolized a liver tumor I had in order to make sure the tumor died. Supposed to have one by the end of the year, but stories like this make me very nervous. The embolization was rather experimental, so checking on it makes sense. I wonder if an MRI would work in this case- I have to have 4 phase contrast images taken to see the blood flow.
    The only issue I ever had was when the contrast agent blew out my vein. They have to inject it rapidly, and I have horrible veins. The scan itself was fine.
    Glad to see this now so I can talk with my doctor about it.

  17. caoimhinnn says:

    I could write volumes on this topic. I’m a second year law student, and I’m concluding a research article on the sort of risk assessment that goes into ordering a CT scan given the potential of cancer decades in the future.

    I don’t have the time to repeat all of my findings, but I will say that there is no certainty with any of this. An increased risk of cancer may or may not exist after each CT scan. There is considerable debate over the model used to predict risk of carcinogenesis following acute radiation exposure. The model that predicts cancer risk associated with ionizing radiation is the linear no threshold model. It predicts that there is an increase in the risk of cancer proportional to the dose of radiation a person receives.

    There are two concerns with the model. First, it is not certain that this model is entirely correct. We have not been able to demonstrate statistically significant increases in the risk of cancer below a certain threshold–somewhere between 50-100 mSv. For reference, a typical abdominal/pelvic CT might expose the patient to a radiation dose of around 15 mSv. We have not been able to prove that radiation at so low a dose does in fact induce cancer. If there is a risk, it is only theoretical at this point, and is based on the LNT model.

    Second, we are unsure if a radiation dose cumulative over time has the same effect as an acute dose of the same value. So, with respect to the atomic bomb survivors (and using made-up figures), let’s say at 10 miles they were receive 100 mSv. They show a small, but statistically significant increase in cancer induction. Here, the survivors were exposed to that radiation in one acute burst. Will we see the same rate of cancer induction in someone who receives a series of CT scans over a greater period of time? Say, a patient receiving medical treatment that gets 4 CT scans per year, each of which serving a dose of 25 mSv. We simply don’t know yet. There is some reason to believe that the result will not be the same.

    The atomic bomb comparison is a little bit “contaminated” because survivors were exposed to more carcinogens than just ionizing x-rays. They were also exposed to gamma rays and particulate radiation, as well as a significant amount of atmospheric pollution. Further, they had their entire bodies irradiated by the blast. Although x-rays tend to scatter, CT scans deliver ionizing radiation in a more controlled way, focusing on one area of the body.

    To comfort any of you who have had scans, even if there is an increase in risk, it is statistically very small, although non-zero.

  18. jjcraftery says:

    My son had a head CT scan when he was 8.
    After that, i found out that hospitals are supposed to adjust the amount of radiation for kids, as they need less to get a clear picture.
    Ever since that day of his scan, I’ve been waiting for cancer to appear.
    And i sometimes get soooooo upset that I let them radiate my kid.
    If I could take back one thing in life it would be that day.
    I look at pictures and my mind categorizes them into “BS and AS”. (before scan and after scan) when he was innocent, healthy, and natural. Then….his growing head recieved radiation all in one shot and one spot.

    Anyone else get a scan when they were a kid? Or know a child that had one and is fine years and years later? I lose sleep over this. I really do.

    • borgia says:

      Brain cells do not divide as you grow up. Cancer risk from radiation is proportionate to the rate of division of the cells. Intestinal, skin and sperm cells are some of the most sensitive to radiation. Brain cells are some of the most resistant to radiation of all cells in the body because they do not divide as you grow up.

    • MauriceCallidice says:

      “After that, i found out that hospitals are supposed to adjust the amount of radiation for kids, as they need less to get a clear picture.
      Ever since that day of his scan, I’ve been waiting for cancer to appear.”

      Do you have any reason to believe they didn’t adjust the dose?

  19. Garbanzo says:

    “If you’ve had CT scans done, has the radiation affected you?”


    Remember Phil: coffee first, *then* blogging

  20. mamacat49 says:

    This is all blown out of proportion. CT scans are the exam of choice for various conditions/situations and MRIs have their own set of criteria and limitations.. If you need a CT scan, make sure you’re at an accredited facility. They HAVE to have the machines checked by a physicist at least once a year. And make sure that the person doing it is a Register Radiologic Technologist (RT(R))—preferably CT registered. Just ask us for our credentials–we’re proud of them and love to tell people about it! And if you can, make sure it’s being read by a qualified Radiologist.

  21. CBenji says:

    I have had three brain tumors. Two years previous to my brain tumors I had a fever of a 104 degrees. My doctor ran labs, but they thought I might have meningitis. To make a long story short they tore my lumbar sac when doing the lumbar puncture and I ended up having several CT scans. Of course I had no brain tumor at the time of the scans. Then bam I suddenly started getting these headaches exactly two years later. My first neurosurgeon told me that I probably had this tumor for many years, but I didn’t agree.

    Of course it came back very aggressively twice, and I working on my fourth round of it right now. I changed neurosurgeon’s on my third tumor surgery when I got tired of making the trek to Philadelphia, plus the tumor was coming back too quickly each time. I am glad I did as this new treatment has been keeping it at bay a bit better. Although I can’t say that the CT scans definitely caused them, it is strange that I had so many of them just two years before this happened. My tumor was a malignant meningioma incase anyone was wondering.