If the Disease Doesn't Kill Ya, the CT Scans Will


There’s a news frenzy about whether doctors are ordering too many CT scans. Right now this article is the most popular article on US News and World Report. A search of Google News shows 368 news articles on the topic from all over the world.

According to an article in the New England Journal of Medicine, doctors are ordering way too many CT scans. Those “unnecessary” CT scans are putting the lives of patients at risk. The article cites a “straw poll” of pediatric radiologists (which appears to be a panel discussion in which the audience was apparently able to vote on questions posed by the panel discussants) who opined that 30% of the CT scans ordered were unnecessary. Let me translate that into non-medical lingo:
“We are a group of sub-subspecialists who perform very little direct patient care and, based on our anonymous and unsubstantiated opinions using retrospective analysis of negative CT scan results, those doctors who do perform patient care should not have performed 30% of the CT scans they ordered.”
So an off the cuff vote at a roundtable discussion is the best evidence that the authors could use to substantiate their assertion that clinicians order 30% too many CT scans. In fact, their article cites this “straw poll” twice:

Tellingly, a straw poll of pediatric radiologists suggested that perhaps one third of CT studies could be replaced by alternative approaches or not performed at all.

then later

However, if it is true that about one third of all CT scans are not justified by medical need, and it appears to be likely, perhaps 20 million adults and, crucially, more than 1 million children per year in the United States are being irradiated unnecessarily.

So what’s the news bite that all the reporters dish out? Doctors order 30% too many CT scans and they are needlessly risking your lives! Way to go, guys.

Before anyone puts any further validity into the opinions of the pediatric radiologists whose straw poll has taken this country by storm, the pediatric radiologists should be required to publish another opinion statement. At a minimum, this statement should contain the following two paragraphs:

  1. Because CT scans are potentially dangerous, we as a society of radiologists agree never to dictate the following sentence into our reports for the rest of our careers: “[insert name of any diagnostic radiology test here] shows no sign of acute pathology. If clinical symptoms warrant, CT scan is advised.” Any time that a clinician sees the phrase “CT scan is advised” they know they have to order one. God forbid that something turns up later on a patient who didn’t get a CT. The radiologist would be the first one wagging his finger on the stand stating “My report clearly states that a CT scan was advised. I have no idea why the clinician didn’t order one.”
  2. As a specialty society whose members have relatively little patient contact and whose opinions can therefore be based solely on RETROSPECTIVE analysis, we hereby PROSPECTIVELY declare that CT scans are unnecessary for each of the following symptoms: [provide the long list of symptoms for which we need no longer do unnecessary tests so that we can save millions of people from radiation sickness].
    No fair including diseases – only symptoms. People with appendicitis don’t come in saying “I have appendicitis”, they come in complaining of “abdominal pain.” The list has to be prospective so all us dumb clinicians know how to properly work up our patients.

After reviewing the strong support for the notion that physicians order too many CT scans, I then went to find out more information about the authors who published this “study.” Guess what? Neither David J. Brenner nor Eric J. Hall holds a medical degree. As far as I can tell, they have never even touched a patient. They are both D. Sc.s or “Doctors of Science.” Dr. Brenner also has a Ph.D. and Dr. Hall also has a D. Phil. or Doctorate in Philosophy in Radiobiology. Both are exceedingly bright fellows, but they are both giving opinions and drawing conclusions that are way outside of their specialties. Both would absolutely be excluded as witnesses if they tried to render an opinion in court regarding patient care.

OK, guys, see this funny looking thing. It’s called a stethoscope. Keep it away from the Bunsen burner. Now put down Immanuel Kant’s biography, walk out of your lab, and use it on a few hundred patients with acute abdominal pain. Then go examine a few hundred other people with headaches. Make your diagnoses. When you’re done and you’ve saved society from all their radiation burns, tally up all the people you’ve misdiagnosed, take time off from defending your lawsuits, and then come back and write your article. Go head-to-head prospectively with someone who walks the walk before you try to talk the talk. Want to write a paper about the different effects of radiation exposure? Fine. You know more about that topic than almost anyone. Leave the recommendations for clinical management to those who actually provide patient care.

Yes, CT scans have risks. CT scans have also been around since the early 70’s. Want to do a good paper? Write an article comparing the rates of different cancers before and after the advent of CT scans. They had the ability to compare real data, but instead used a prestigious journal to scare the public by stating that the radiation from a few CT scans is like being near ground zero at an atomic bomb blast. Shame on NEJM for publishing this article.

If you want to become famous, go make a funny YouTube clip. In the meantime, don’t degrade our profession.

P.S. Does this groundbreaking study mean that we should just keep doing invasive angiograms on patients rather than evolving and doing CTs to rule out coronary disease? Don’t want to get heart cancer, ya know.

UPDATE 12/03/2007

Something else keeps running through my mind about this whole issue.

Let’s suppose the assertion(s) that 2-3 CT scans are equivalent to an atomic bomb blast and/or one CT scan increases your chance of cancer by one tenth of a percent is/are true.
Will society be willing to accept the trade-off of not receiving a CT scan to decrease one’s potential cancer risk? We won’t do the scan, but you assume all responsibility if we are not be able to diagnose your traumatic incracranial bleed, your aortic aneurysm, your pulmonary embolism, your lung cancer, your cervical spine fracture, etc.?
This is another reason I think the NEJM article has no good purpose. If a physician performs an ultrasound to reduce radiation exposure and therefore misses an important finding, the patients suffer and the physician can be sued for not doing the “proper test.” If physicians order an MRI instead of a CT to reduce radiation exposure, then they find that access to MRIs is limited, insurance won’t cover the exam if the MRI is available, and then patients complain that healthcare costs are going through the roof. If physicians order a CT scan and patients later develop cancer, the physicians are to blame for performing the CT scan and causing the cancer.

Fear the bad outcome.

Anyone have a suggestion as to how we should “do right” in this quagmire?

Do we now need to create informed consents citing the speculative assertions of a bunch of unnamed pediatric radiologists in order to prevent a flurry of class action lawsuits 5-10 years in the future?

UPDATE 12/10/2007

Lifting a box then getting RLQ abdominal “twinge.”
A day and a half of RLQ pain with normal white count.
Left upper quadrant pain with no fever, no appetite, and WBC count of 23k.
To those who actually believe that 30 percent of CT scans are “unnecessary,” on how many of the above cases would you have prospectively ordered CT scans?
All of them, right?
After all, they were all positive for appendicitis.
Thanks to Ten out of Ten for the interesting cases.


  1. if you didn’t do the ct scans, patients, families and a few nurses i can think of would be screaming “do the scan!!!, why aren’t they doing it? then we would know what was wrong!”
    and yup you would all get sued.

  2. Good point. This paper sets the docs up for another no-win situation. If you don’t do the scan, you miss something, and there’s a bad outcome, you get sued. If you do the scan and the patient later gets cancer, you get sued. Doesn’t make the practice of medicine any better – just teaches the doctors to fear the bad outcome.

  3. Just want ya to know Whitecoat this post is freaking me out…just a little. Although you’ve softened it a bit. 🙂

    I read on someone’s blog recently that 1 abd ct is the equivalent of 500 chest x-rays. So THAT’S why we don’t need lights when I am in the house! 😉

  4. I would suggest that yes, perhaps it is too soon to adopt CTA as the test of choice for ACS. Our affiliated tertiary university just had journal club in which recent CTA research was discussed. The consensus was that CTA was beneficial to r/o CAD in the low risk pt, but that it was not more effective than ETT or nuclear; the cost benefit was not significant, but the time involved was shorter.

    A dual trained cardiologist/radiologist mentioned that he had been at a meeting in San Francisco with all the bigwigs in cardiac imaging. When asked if they felt CTA was ready for prime time he said not a single person raised their hand. Perhaps with the 128 MDCT scanners, dual source scanners or improvements in image acquistion w/ gating the radiation dose may be lowered. But we are not there yet.

    The radiation from CTA is significant. If you then need cath, PCI and perhaps nuclear imaging as well you could end up with a large amount of radiation exposure in a short time. And that could be the result of only one episode of ACS. If you are unfortunate and have restenosis or progressive disease and have another ACS epsiode, then cumulative radiation exposure would not be trivial.

  5. When is a CT advisable, versus an MRI? I assume there is no risk to an MRI since it uses magnets but I’m not a dr or a scientist.

  6. Well done! I hope the people who wrote the paper see and respond to your suggested paragraphs. It’s been a career-long frustration for me, the recommending of further studies or even surgical interventions that show up on radiology reports.

    (Unimportant point: I think that in the UK some D.Sc degrees are the same as MD, but I don’t feel like looking it up. Even if true, it doesn’t change the right-on-ness of your post.)

  7. CT scan radiation killed my son either by causing or heavily contributing to his Acute Myeloid Leukemia dx and subsequent death.
    He had 5 CT in a two week period at the age of two due to traumatic head trauma as a result of an auto accident. Five years later ( typical latency period from exposure to cancer dx can be anywhere from 5-20 years). At the age of 7 he was dx’d with AML.
    I would like to see a study of the rate of cancers pre CT scan usuage vs today when medical radiation is greatly used as a diagnostic tool.
    By the way, MRI has no ionizing radiation.
    J. Dansmom

  8. J. Dansmom,
    First, I couldn’t imagine what it would feel like to lose a child. That alone is one of the biggest fears I have in my life. I don’t want to take away from the suffering you, your son, and your family experienced.
    I’m not going to sit here and tell you that CT scans did not cause your son’s cancer. The problem is that no one will ever know for sure.
    I would caution you and everyone to be cognizant of the logical fallacy known as “post hoc ergo propter hoc” or “after, therefore because of.”
    Until someone takes the time to compare cancer rates in those having CT scans versus cancer rates in those who have not had CT scans (taking into account the increase in certain types of cancer attributable to HIV which was discovered shortly after CT scans hit the mainstream), I think it is improper to draw the absolute conclusion that CT scans are to blame for all the new cases of cancer in this world.
    I’m not saying the correlation does not exist. At some point, proper medical research may prove the correlation and the risk involved.
    Until that time I don’t think fear-mongering is appropriate.

  9. Whitecoat,

    Wouldn’t there be a confounding problem of an increased detection rate of many cancers since the 70s and differences in data collection/reporting methods and that sort of stuff?

    Wouldn’t it just be better to simply compare rate of cancers in people with CT scans (not related to the cancer of course) vs. healthy controls? Maybe start with people with more than 20 or 30 CT scans in their lifetime and work your way down. Of course, determining the exact # of CT scans for many people will be a problem, especially those who get 10 or more each year every year, like our frequent flyers.

  10. Nurse K:
    Not a bad idea, but if you divide the world into 2 parts, those who have never had a CT and those who should have (but never did), the right half will in general be sicker than the left half and would have more cancer and other illnesses, even in the absense of any actual CT scanning. This is a major confounding variable. In addition, background radiation is not insignificant. Two 40 year olds, one lives in Denver and the other in Seattle, the first has had a collective 124 mSv (say 10 CT scans equivalence) while the mile high guy has accumulated 220 mSv (say 20 CT scans). Lots of confounding factors make it virtually impossible to detect something that has a 0.4% probability of happening.

  11. Whitecoat,
    I did misrepresent my view point and I do apologize for that.
    I do believe that CT radiation could very well have been a contributing factor and not the single cause of my son’s AML. Perhaps it was part of the Two Hit Theory, i.e he was genetically predisposed and the radiation was the ‘trigger’.
    No one will ever know and I would love to see a study of leukemia rates in children who were xrayed at some point in thier life vs a group of controls who wasn’t. I know it would be nearly impossible but one can never stop wondering. I am a big fan of the late Alice Stewart, the Enlgish Physician “who knew too much”.
    Either way, we should all be vigilant when it comes to our children and keep a ‘radiation history” card on each patient so that when one doctor orders a CT for a certain ailment, he might re think it if he knows the patients radiation history and sees that the patient has had scans in the past. Also, informed consents should be present when a CT is ordered for a patient explaining the risk v benefits of the scan.
    J. Dansmom

  12. Just for the record: Dr. Hall probably knows more about Radiobiology than you ever will (no offense). You may have read his classic textbook: “Radiobiology for the Radiologist”. He IS an expert in this area of work …

    Just saying…

  13. Chris –
    No offense taken to your comment, and I agree. If I had an issue on radiobiology, he’d probably be my go-to guy. He could probably talk circles around me regarding the effects of radiation on the body.
    However, expertise in one area doesn’t endow you with expertise in all areas. He’s not an expert in law, an expert in architecture, or an expert in electrical engineering because he has no experience in those areas (at least according to his CV).
    Similarly, he has no experience in patient care. When a non-clinician who has never engaged in patient care tells a lifelong clinician how to practice medicine, to me that comes close to a breach of medical ethics. Using some silly ad-hoc straw poll of a bunch of unnamed non-clinician radiologists as the sole basis for telling clinicians that their practice of medicine is fundamentally flawed only compounds the egregiousness of his paper.
    If I wrote a “a scientific study” about how fundamentally flawed all Dr. Hall’s radiobiologic research was and used a straw poll of the physicians visiting this blog as “proof,” do you think it would be well received in the International Journal of Radiation Biology?

  14. You guys are being too hard on the authors. The actual statements in the paper are a little mushy anyway. Did anyone RTFA? I did. Two examples …

    “Computed Tomography — An Increasing Source of Radiation Exposure (Fig. 2), this estimate might now be in the range of 1.5 to 2.0%.”

    “The second is to replace CT use, when practical, with other options”

    I could quote more and more. It’s all wishy-washy stuff. Some stuff they write that’s unsupported is more troublesome but no one here is complaining about that. They don’t indict doctors in this paper and they may be right to bring attention to the possible over use of X-rays.

    They site two sources that CT may be overused, NOT just one. They also sited data that doctors underestimate the dose from CT. That’s not insignificant. In my personal straw poll, doctors are completely ignorant about radiation dose all together.

    The real problem may be the BEIR VII report. There is a huge battle between “threshold” and “no threshold” effect models in health physics.If you don’t know what that is go read Hall’s book 😉 It also might have been better for the authors to include a radiologist as a coauthor too.

  15. James R. Marbach, PhD, DABR on

    I have been working as a Clinical Medical Physicist for over 30 years. To all you “whitecoats” who are unaware, physicists have been in the Radiation Oncology Clinic making sure the patients actually get the radiation dose the physicians prescribe since Conrad Roentgen (a physicist) started the whole thing back in 1895. As a primer for all you “experts” in radiation effects, the application and efficacy of ionizing radiation in curing cancers is based on the radiobiology gentlemen like Brenner and Hall provide. If only you “whitecoats” would take the time to listen to them, you might actually learn something. One thing you can be assured is that if these people aren’t respected for what they know and provide to the medicine knowlege base, you can believe that utilizing the high technology methods in treating with radiation that are evolving will create some, for lack of a better word, interesting litigious events in the future. Since many of you have opted to build your own radiation therapy centers, you might do well to brush up on the physics fumdamentals that are the basis for this very successful treatment modality. By the way, if you want to ignore what these fine experts have to say, just wait around, the government regulators will take care of things.

  16. I would be interested in reviewing a paper by the medical physicists about the proper utilization of CT scanners in clinical practice.
    You both are missing the point.
    I completely agree with you that the radiation from diagnostic testing is not harmless. If clinicians don’t know this, they should.
    I completely disagree with non-clinicians (both radiation physicists and pediatric radiologists) telling clinicians how to do their jobs. Checking the proper dose of isotopes in some clinic for thirty years does not entitle one to opine on proper diagnosis and management of abdominal pain, headaches, trauma, chest pain, and the plethora of other misfortunes that are imaged every day. I hardly know anything about radiation therapy. I’d be embarrassed to publish a paper trying to tell radiation physicists how to do their job. So if you take offense at my hypothetical suggestion of someone who knows very little about radiation physics publishing a paper questioning a medical physicist’s research, why do you find it perfectly appropriate when the tables are turned?
    This is not an issue between physicians and radiation physicists and no one one is ignoring what these gentlemen have to say. Part of their paper was informative and educational.
    The issue is that in the remainder of their paper, these “scientists” overstepped their bounds. They know nothing about patient care, yet provided baseless criticisms on all the dumb “whitecoats” who overutilize diagnostic imaging. So tell me how to do it better and don’t use calumny to support your opinions. Part of their paper appears to have been designed solely as a means to scare the hell out of the public. Congratulations. It worked.
    If these types of actions are appropriate in a medical physicist’s world, then maybe the public should stop listening to them.

  17. So you say they “provided baseless criticisms on all the dumb “whitecoats” who overutilize diagnostic imaging” One, I don’t think they are being too critical and two, the claims are not baseless.

    The basis is that the best information tells them that low levels of radiation can cause cancers and also that the radiation dose from CT scans in increasing. That’s a good basis and they provide many references to back it up. They only thing you seem to be hung up on is that they claim CT is over used.

    If you look at ref’s 6-13 they site CT SCREENING papers. Screening patients that: weren’t in a car accident, aren’t coughing up blood, aren’t shot, maybe don’t have a headache … People that are otherwise healthy despite the fact that they may smoke or are old. You can’t argue that every whole body CT is done is done with good justification. Some hospitals advertise for that service to the public!!! Ref’s 36-41 (I’m excluding the straw poll) mention over use of CT. I’ll assume that MDs published those papers not physicists (swallow the bitter pill from your own colleagues). I’m going to guess that you didn’t bother to check the ref’s and so you’re rant is from a position of ignorance.

    In our area doctors and physicist work together closely. We trade opinions all the time and work together to achieve good outcomes for our patients. If you want to spout off like Judge Dredd and scream “I am the doctor!” go right ahead. I’m going to give the the benefit of the doubt and assume that sounding unintelligent makes the blog more fun to read and that’s why you do it.

    RTFA doctors. RTFR too.

  18. Medical Physicist in Jamaica on

    I am a Medical Physicist in Montego Bay Jamaica. Presently, we are in the process of commissioning the first CT scanner at the hospital where I work. My greatest desire after reading this blog is to be in a position where I can initiate a similar lively discussion with my doctors on the overuse of CT, hopefully on a blog like this one.

  19. Medical Physicist in Jamaica on

    Personally, I believe that, if it’s not a medical emergency, doctors will always err on the side of caution when it comes to requesting diagnostic tests including CT, lawsuits or no lawsuits. All this issue, with the possible exception of whole-body CT’s on otherwise healthy subjects, is a case of “You’re damned if you do… but more damned if you don’t”.

  20. Med Phys –
    I’ll not belabor the point because it reminds me of the old movie “City Slickers.” The cows will get it before some spurned physicists do.
    I’ll make it simple:
    Radiation = bad. No disagreement. Good paper. Good paper.
    Causing media circus by making uninformed statements outside your specialty (even outside your profession) without knowledge, without providing substantive basis and without providing solution to problem = bad. Big disagreement. Bad paper. Bad paper.

  21. Pingback: At The Radiologist’s Mercy « WhiteCoat Rants

  22. To #25 ‘Med Phys’…. WOW!! I’ve heard the flat Earth Society still exists but here you crawl out of your cave. Did you have the medicine man read some chicken entrails for that gem? Millions of patients have not only survived “Radiation = bad” but they seem to STILL be walking the planet! Or has your voodoo doctor explained that the Evil Oncologists are creating an army the walking dead? (side note Moron – Med Phys refers to doctors treating cancer with radiation) If your going to try and cloak yourself as one with an education at least make sure you don’t choose an appellation of the profession your lambasting.
    Radiation = good
    There are far to many people who have a fear of radiation based on ignorance. Your pithy comment perpetuates this fallacy.
    To wit: RADIATION IS GOOD IN CANCER MEDICINE FOLKS. I know as my mom lives today because of oncology. Further, my father and his colleagues have saved millions of lives with oncology. Fear the Fools of the Flat Earth Society not the doctors who will save your loved ones lives.
    ps: #25 ‘Med Phys’ please go back to your cave…….

    Hi. Me Grog. Me come out of cave today.
    If you read the quote that you criticize, you would see that it is from WhiteCoat, not from ‘Med Phys’ – don’t worry, I’m sure he’ll understand.
    What is with you Marbachs? Now there’s two of you with hurt feelings because you can’t understand the difference between clinicians and non-clinicians. Nevertheless, you did have an amusing post. You have a future in ranting.
    If radiation is good, then the whole premise of the paper is shot, now, isn’t it? Make up your minds. Or are you only stating that the radiation in radiation oncology is good and all the other radiation in the world (including diagnostic radiology) is bad? If so, how would we find all those tumors that you and your colleagues so laboriously treat?
    “There are far to many people who have a fear of radiation based on ignorance.” That is EXACTLY the point of this whole post. Read it again, Einstein. I’m not going to repeat it.
    From the movie City Slickers:
    Shut up! Just shut up! He doesn’t get it! He’ll never get it! It’s been 4 hours! The cows can tape something by now! Forget about it … please!

  23. I have to add to the ‘whitecoats’. Your belief that medical physicists are unimportant in akin to the air traffic controller telling me the pilot is unimportant. Finally, Your illustrious schools may have failed to mention — a PhD IS a doctor! The D in PhD is Doctor. I wonder how many of you ‘whitecoats’ hold doctorates in your respective specialties.

    Sorry … have to squeeze … a … comment in here. Your ego is so big … the space … is … limited.
    I’m wondering if your exposure to all that radiation has turned on some megalomania gene in your system.
    Great comparison – clinicians are the air traffic controllers and doctor radiation therapists are the pilots. The pilot doesn’t tell the air traffic controller how to do his job now, does he? At least he shouldn’t. “Hello, tower. This is Alpha-One-Niner. Keep all those other planes waiting for me while I butt my way in line and take off when I dang well feel like it. Roger, Wilco.” Apparently you doctor radiation therapists haven’t learned the premise of an analogy.
    One quote in a kids movie that made me laugh was made by Doctor Doppler in the movie Treasure Planet. One of the characters asked him for help after being injured. His reply:
    “Dang it, Jim. I’m an astronomer, not a doctor! I mean, I am a doctor, but I’m not that kind of doctor. I have a doctorate, it’s not the same thing. You can’t help people with a doctorate. You just sit there and you’re … useless!”
    Don’t throw stones … doctor … even if they are radioactive ones.

  24. Medical Physicist in Jamaica on

    I am “Medical Physicist in Jamaica” from posts #23 and #24 and different from “Medical Physicist” in posts #19 and #22. I wonder about the intended direction of those comments about “medicine man”, “voodoo doctor” and “chicken entrails” in post #27 by Eric Marbach. Given from his vision problems, I cannot help but chuckle at his petty prejudices.

  25. CT scanning has saved vastly more people by detecting problems than they have killed through radiation exposure. So, overall, CT scanning is very good.

    However, in my hospital in the UK when a patient has medical insurance, the radiologist that will authorise the radiation exposure of the scan is the same one that will report the scan and be paid for doing so. This seems to me to be a conflict of interest and not good.

    Physicians – keep asking for CT scans when you think they’re needed
    Radiologists – authorise the requests when they’re justified, reject them when they’re not
    Radiographers / technicians – keep making sure you get the best images possible and avoid repeat exposures

    Most people are just trying to do their job as best they can – it’s a lot easier if you co-operate and combine expertise from the different areas.

    (oh, and as regards possible pulmonary emboli, send them for a nuclear medicine V/Q lung scan – it’s comparable to CT in terms of sensitivity and specificity, but with less radiation dose)

  26. Shoot! I never thought of repeats…that happened to me with my 2nd CT!

    If them telling me while still in the machine or just outside that they are doing it again…that is what they did.

  27. Working my way backward through the archives (and enjoying every minute of it)…

    This is a no-brainer. Obviously, the answer is to stop doing CT scans and resume doing exploratory surgery.

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