Scientist Smackdown: Are Unnecessary CT Scans Killing People?

By Andrew Moseman | December 16, 2009 3:12 pm

Ct-scan425Are CT scans putting thousands of people in unnecessary jeopardy for cancers and death? That was the suggestion by two new studies out this week, leaving radiologists scrambling to explain the true level of danger to worried patients.

A CT scan, also known as computed tomography, gives doctors a view inside the body, often eliminating the need for exploratory surgery. But CT scans involve a much higher radiation dose than conventional X-rays. A chest CT scan exposes the patient to more than 100 times the radiation dose of a typical chest X-ray [Reuters]. However, a study out of the University of California, San Francisco says, we might not have as good a handle on CT radiation as we thought. The researchers found that radiation differed greatly between machines, and some emitted 13 times more than others.

A separate study, published in the same journal—the Archives of Internal Medicine—cited those radiation levels and the fact that CT scans have grown tremendously (from 3 million in 1980 to 70 million in 2007) to try to quantify the danger. Excluding scans performed after a cancer diagnosis and within the last five years of life, they calculated that the scans would contribute to about 29,000 cancers in the next 20 to 30 years [Chicago Sun-Times]. They also estimate that half that number could die.

Some radiologists questioned this methodology. The estimates of cancer cases caused by CT scans were based on the rates of cancer that occurred in people exposed to radiation from the atomic bombs dropped on the Japanese cities of Hiroshima and Nagasaki at the end of World War Two. But many experts disagree on whether that model offers a fair comparison [Reuters]. The American College of Radiology said that wasn’t necessarily a fair standard because CT-scan patients expose only a small portion of their bodies exposed to radiation. And, the organization of 34,000 radiologists argues, CT scanners today produce lower doses of radiation than those two or three years ago.

Because CT can save lives by catching diseases, and because an individual’s chance of getting cancer from any one scan are quite low, the question at hand becomes when it’s worthwhile to do the scan. “Nobody knows how many CTs are too many, but I would estimate about 20 to 30 percent of the scans are not necessary,” said Dr. Rebecca Smith-Bindman, a radiology professor at UCSF and lead investigator of the study [San Francisco Chronicle]. And then there’s the other elephant in the room: money. Those scans are pricey and can bring in big money to doctors practices, hospitals and imaging centers. At a time when the nation is trying to rein in health care costs, could more prudent use of CT scans help [Baltimore Sun]?

Just about everybody in this scientist smackdown agrees on one thing, though: If you’re getting a CT scan, talk to your doctor about why he or she thinks it’s necessary.

Image: Wikimedia Commons / NithinRao

CATEGORIZED UNDER: Health & Medicine
  • Palin in O12!

    Yet another example of propeganda from the death panel. Obama needs you to believe that it costs too much for healthcare, so they can kill old people like they do in Russia.

  • lyllyth

    Um, actually there is nothing in this article about costing too much.

    It’s about using something medically unnecessary when there are better options and reducing risks to public (you know, consumer) health.

    I see nothing wrong with preventing overexposure to radiation. Ask anyone near Chernobyl.

  • Brian Too

    I’d urge caution in limiting the use of CT scans before the medical support systems catch up.

    Let’s not forget that these are non-invasive techniques. We don’t want to go back to the era of exploratory surgery. If we have a better alternative then sure, let’s go for it. However to limit non-invasive diagnostics simply because, at the population level, we have “too many” is almost certainly a bad idea. There’s a set of clinical indicators and those need to be followed.

    What do I mean by medical support systems? Well, that comprises the EMR’s, RIS’s, PAC’s, HCIS’s and are being implemented widely as we speak. We also need to get to a stage where information sharing between discrete systems, with appropriate controls of course, is routine and reliable.

    Then we can start cutting down on the number of CT’s, MRI’s, and all the rest. If a current test exists but someone else did it, then by all means use the prior diagnostic test results. Right now clinicians often cannot access other test results and if they can it’s often not timely. This mostly happens when the prior test result is from “out of system”, whatever and however you wish to define that term.

    Oh, and not to be pollyanna about it. This will get done primarily for the cost benefits. It will only secondarily be done to reduce patient radiation exposure and all the rest of the clinical benefits. However it will get done because there are cost drivers behind it.

  • memory foam

    A statement that catches the eye is : “The researchers found that radiation differed greatly between machines, and some emitted 13 times more than others. ” — this is an unacceptable situation and should be readily resolvable. Hospital machines should be subject to inspection and standards similar to workplace machines. No reason the machines shouldn’t all be designed to the lower levels of output.

  • Bill

    You know, the CT scan I had to help diagnose my vertigo (instead of a brain tumor) was a lot less invasive and a lot more conclusive than ANYTHING else medical science could have offered. I would much rather be exposed to a bit of radiation (and working in Delaware, it’s the least of my worries) than agonize over whether I had cancer or not. No one is ever forced to receive a CT scan and if you’re not familiarizing yourself with the tests and procedures that are being conducted on YOUR BODY, then you have no right to be angry about this. This is not new, people have been arguing the merits and risks of radiation based tests ever since the first X-Ray was performed.
    The fact that these machines differ so much in radiation exposure to patients is most likely do to the age of the machine. The newer the equipment, the less radiation it exposes you to. Therein lies another problem: If these machines vary so greatly on the amount of radiation exposure, how do we get these old machines replaced with new ones? Who’s going to pay for this? Hospitals already can’t afford to keep adequate staff on board, how will they afford these machines? Health Care Reform goes so much deeper than insurance………….


    Cash for clunker CT’s???

  • Bill J

    Your right Bill! Overexposure to Joe Biden is far more dangerous that 2 couple of CT Scans!!!! Who knows! Joe may be Al Gores’ long lost brother!!!

  • Bill J

    On the serious side, I’m a 70 yr old male with a target on his chest & ObamaCare taking aim! At my age; treatment for anything more than a minor illness (read cheap treatment) will be denied. Morality aside, forcing senior citizens to die off will result in enormous savings! It’s been said that “Old people have a duty to die and get out of the way!” and it seems that the Congress is determined make sure that happens! For those of you who believe in that policy, I have but one question! When your time comes, will you go quietly unto that dark night???

    If the health care bill becomes law, sooner or later the Death Panels await!!!

  • Eliza Strickland

    Bill J:

    You’ve posted 12 comments recently which have very little to do with the science discussed in the posts, and quite a lot to do with Al Gore, Barack Obama, and Hillary Clinton. This isn’t a political blog — please find another forum to discuss your political opinions.

    Eliza Strickland
    DISCOVER Online News Editor

  • Ben Russell

    Point well made Eliza !!!!

  • George Holmes

    Maybe BILL is a secret Tea-bagger. Or not so secret one-who knows. I can say that as well as he can say what he has spewed forth in his comments here. I am almost 75 and 5 years ago had the full monty at MD Anderson Cancer Center in Houston Texas. Know how much it cost me? Nothing, nada, zilch. Yet without medicare, etc it would have cost me $75,000 and since I am not a rich retiree I would have had to opted to go ahead and die. My wife, 4 kids and 9 grandkids certainly would have something to say about that.

    Oh, please pardon me if I ran off at the mouth to much, but people like Bill writing stuff that has no bearing on the article in question make me sick.

  • Jenelle

    Why do those who are against Tea Party members insist on using the derogatory term, ” Tea-bagger?”
    Where is the tolerance for those who aren’t liberals? Why can’t you simply respectfully disagree? Your words says volumes about your character. Martin Luther King, Jr. wanted us to judge one another by character.

  • Gary Wannlund

    [Health Care Reform] Obamacare [is going to|will no doubt|is designed to|will definitely|will certainly] [have|cause|produce] [unforeseen|unpredictable|unnecessary] [consequences|results|issues|problems] [that most|that the majority of|that almost all] [people are|citizens are|consumers are] [not|not really|not even] [noticing|seeing|realizing|paying attention to]. [I guess|I imagine|I suppose|Maybe] [it’s|it truly is|it is really] [hard|difficult|tough|challenging|tricky] [with|due to] [a law|legislation] [so long|so huge|so massive] [that|which unfortunately] [no|absolutely no|simply no|virtually no|certainly no] [human|human being|person|individual] [would be able to|are able to] [fully understand|completely understand|understand fully] [it|the law|the legislation] [even if|even when|regardless of whether|whether or not] [they|they even] [read|look at|read through] it. [I|My partners] [sell|market] [health insurance|medical insurance|health care insurance|medical care insurance] in [Tennessee|TN], and [we|I|we all] [just|basically] [had|just had] our [pay|compensation|earnings|salary] [cut|reduced|slashed] by [over|more than|greater than] [half|fifty percent|50%|one half|50 %]. [I|We] [wish|really wish] [someone|somebody|some-one|anybody] cared [to|enough to] [protect|offer protection to] [small business|work from home business] [people|owners].

  • Renae Seuell

    You made some good points there. I did a search on the subject matter and found most people will consent with your blog.

  • Ronald Lavine, D.C.

    Good article.

    The point that jumps out at me is “If your doctor suggests a CT scan, be sure to discuss why it’s needed.”

    This is good advice in theory but my experience is that the doctor ordering the scan already thinks it’s the right thing to do and thus will always have a convincing argument to assure the patient that in fact the scan is needed.

    One of the few ways to address this issue would be if the prescribing physician actually experienced a financial dis-incentive to the ordering of tests, rather than the current set-up in which the physician has a financial incentive to order tests.

    Maybe there’s a creative economist out there who can figure out a way to do this.

  • Summer

    An inexperience M.D. ordered a CT scan for me once, after a snap judgment that I had a major problem. I doubted her diagnosis and didn’t want all the excess radiation, so she switched to wanting an ultrasound scan. Turned out that she was completely wrong. But if I had not been dubious, and squeamish about needless radiation, there would have been a lot of money wasted, and increased risk to me.

    Of course if she had been invested in a CT scanner, and a lot of MDs are, in one way or another, it would have been more of a problem.

    Still, it is important to remember that the alternative to CT scanning is not always surgery. An second opinion is always an option.

  • Steve

    It’s stupid physician assistants who are ordering unnecessary cat scans. They don’t know how
    to read x-rays so they order a scan. They radiologist has to. Read it.


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