Studies Quantify Cancer Risks From CT Scans

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The assumption of a linear dose response to very low (relative) radiation dose levels has no scientific basis or proof. Extrapolations from the one time, extremely high radiation exposures of nuclear bombs to the relatively low dose levels of medical x-rays, has no validity or scientific validation. We do not assume that low level sun exposures summed over a life time can be equated to short time, extremely high UV exposures in inducing cancer. The general public can quickly understand and reject this assumption. Low levels of many substances, minerals, vitamins, etc are vital for life, yet consuming half a lifetime dose at one time of many of these may be fatal. It is untested to assume x-rays behave in a different biological way. Radiation exposures were much, much higher for radiologists 20 plus years ago due to frequent x-ray fluoroscopy with the radiologist directly in contact with the patients. I have measured these dose levels and recorded cumulative doses over years. The induction period for cancer is on the order of 10 to 15 years. Why then do not radiologists have an extremely high cancer rate? The assumption of a linear dose response to low radiation levels with cumulative effects has no proven basis.

Ben Arnold, Phd, MPH of KY 4:40PM August 01, 2010

Media coverage of the two recent studies published in the Archives of Internal Medicine, claiming increases in cancer due to use of computed tomography (CT), raises vital public policy issues that must be considered.
First, it’s important to understand that medical imaging manufacturers have made incredible strides in innovating advanced equipment that minimizes radiation dose. In fact, new medical imaging technologies and systems introduced during the past 20 years have significantly reduced radiation dose.
Even with this progress, manufactures continuously explore the next frontiers of innovative medical imaging technology that will exponentially reduce radiation exposure while exponentially increasing the capability and quality of the images it delivers -- allowing physicians to save more lives. To that end, we believe policymakers should encourage technologic development so that companies can continue to innovate and produce diagnostic equipment that reduces radiation dose and improves patient outcomes.
Next, while nobody disputes the effectiveness of CT scans, the assertion that CT scans are overused is an outdated perception. In fact, an analysis of Medicare claims data from 1998-2007 demonstrates that beginning in 2007, spending on advanced diagnostic equipment decreased by 19.2 percent while volume grew by a modest 1.9 percent. Any claims that the use of CT is rapidly growing is false.
Imaging manufacturers believe that the way to continue driving proper use of CT, as well as other diagnostic equipment, is to ensure physicians have access to, and are relying on, evidenced-based guidelines at the point of care to determine which diagnostic test should be ordered (or not ordered). That’s why MITA strongly endorses a robust build-out of appropriateness criteria in the Medicare program, and research supports this approach. This is the best way to drive proper utilization while ensuring patients have access to the diagnostic procedures they need.
Lastly, it’s important to point out that medical imaging, when used appropriately, minimizes other risks that more invasive procedures present to patients, and enables doctors and patients to more effectively tackle the very real and very deadly diseases they already have. We must preserve access to these scans while smartly fostering the development of new technologies and ensuring their proper use.
Dave Fisher
Managing Director
Medical Imaging & Technology Alliance (MITA)

Dave Fisher of VA 2:58PM December 16, 2009

cOMPUTING THE PROBABILITY THAT A DOSE OF RADIATION WILL CAUSE CANCER OFTEN USES A LINEAR DOSE RESPONSE AS IT IS CONSERVATIVE. iF THIS METHOD WERE USED, THE CALCULATED NUMBER OF EXCESS CANCERS IS AN UPPER BOUND AND COULD MISR5EPRESENT CANCER RISKS BY ODERS OF MAGNITUDE.

Allan M Salzberg MD PhD of ID 11:56PM December 14, 2009

Here an educational website for adults to calculate radiation dose and estimate risk:
www.xrayrisk.com

Mike Hanley of SC 8:17PM December 14, 2009

Perhaps you could also publicize what the radiology community is doing to educate referring clinicians about the dangers of ordering tests which may not be indicated. The dangers are highest in the pediatric community and so that's where tje focus has been centered. You can learn more at the website:
http://www.pedrad.org/associations/5364/ig/.
Unfortunately physicians who are not radiologists aren't required to receive training on the appropriate use of medical radiation and its biologic effects. This has fostered a dramatic increases in the number of CT scans being performed within these doctor's offices just over the past 10 years alone. There are currently too few insurance requirements in place to prevent such self-referral. Radiologists can provide an extra check to ascertain clinical necessity but some non- imaging trained physicians seek to bypass even this small step to prevent unnecessary patient radiation.

Samuel Jopatelli of PA 7:50PM December 14, 2009