CAT Scans Can Kill You

In the year 2007 we performed 72 million CAT Scans in the US.  72,000,000!  That’s over 19,500 per day.  Every day.  A CT scan can have as much radiation in it as about 100 X-Rays.  We do them for all kinds of reasons.  A patient shows up at the ER with abdominal pain.  We know they just ate way too much hot sauce at the local Mexican joint a few hours ago but it “could be” appendicitis.  We do a CAT scan “just to be sure.”  A patient comes to the office with a history of terrible headaches.  We know she’s in the middle of an ugly divorce, her kids are flunking out of school and that CAT scans are very unlikely to lead to any real diagnoses with regard to headaches.  We order a CAT scan anyway, “just to be sure” it isn’t a brain tumor.  In the end we order lots and lots of CAT scans.  So here’s the problem with trying to do the right thing as a doctor, i.e. NOT order a CAT scan when you know it’s unlikely to help the patient:  there are ZERO dis-incentives.  And LOTS of incentives.

For one thing it’s a CYA policy.  So far as I know no one thus far has been sued for ordering a CAT scan.  Lot’s of people have been sued for NOT ordering one.  Second, the patients usually feel like you are being thorough when you get one.  We Americans love our technology and the CAT scanner is so ultra cool we really really ought to be using it as often as possible no?  And then if you are the radiologist or the hospital you make a TON of money doing these things.  Now that we don’t even actually develop the films (they just come over a computer monitor) It really doesn’t even cost much to do them (But we still bilk the insurance companies, or, if you are unlucky enough to be un/under insured, you).  So lot’s of incentives and hardly any dis-incentives.

Except this one, as pointed out in a series of article in 2009 in the Archives of Internal Medicines[ii][iii], we’re killing people by giving them cancer.

It doesn’t happen very often;  about one out of every 270 times.  It’s not likely that your CT scan is going to kill you.  But it might, and you should probably know that before you agree to one.

Now sometimes it’s literally a no-brainer and you really should get one – you just got your head smashed in and we’re thinking you might have bleeding that needs surgery.  Get into the scanner!  But often it’s way more subtle; you’ve had some weird belly pain off and on for the last few months and the doc wants to get a CAT scan of your belly.  Think about it before you agree.

So if one out of every 270 patients of our 72 million customers is going to get a life ending cancer, BECAUSE OF THE CANCER, how many are we killing?  Simple math, over fifteen thousand people who got CAT scans in 2007 are going to get cancer and die BECAUSE of the CAT scan.  Not from the ‘disease” or symptom that prompted the CAT scan, but from the CAT scan itself.  I doubt any of the doctors of those patients will even think that the CAT scan they ordered was the cause of the cancer.  In fact they will probably find the cancer by doing another CAT scan and pat themselves on the back for being so through!  I doubt many of the patients will think the cancer was caused by a CAT scan done years ago – but it was.   I doubt any of them will sue (and if they did they would have a really difficult time proving it, even though the data is pretty conclusive.)  None of the doctors wanted to cause harm to there patient.  They were just being thorough.  Nonetheless, the doctor was killing them “and he didn’t even know it.”


[i]             Cancer Risks and Radiation Exposure From Computed Tomographic Scans.  How Can We Be Sure That the Benefits Outweigh the Risks?   Rita F. Redberg, MD, Msc  editorial in   ARCH INTERN MED/ VOL 169 (NO. 22), DEC 14/28, 2009

[ii]          Berrington de Gonza´lez A, Mahesh M, Kim K-P, et al. Projected cancer risks from computed tomographic scans performed in the United States in 2007. Arch Intern Med. 2009;169(22):2071-2077.

[iii]              Smith-Bindman R, Lipson J, Marcus R, et al. Radiation dose associated with commoncomputed tomography examinations and the associated lifetime attributable risk of cancer. Arch Intern Med. 2009;169(22):2078-2086.

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