Scientists warn FDA about CT scans

CORRECTION: The original version of this story incorrectly stated MRI machines emit radiation. They do not. The transcript below has been corrected.


Bob Moon: Early detection of diseases has made CT scans more popular with doctors than ever. Americans are also exposed to a lot more radiation as a result. Today, the Food and Drug Administration will hold a hearing where its own scientists will urge the agency to be more careful about the scanning devices it approves. From our health desk at WHYY in Philadelphia, Gregory Warner reports.

Gregory Warner: A decade of research has shown that just owning a CT scan makes doctors more likely to use them.

Dr. David Levin is former chairman of radiology at Thomas Jefferson Hospital in Philadelphia:

David Levin: The cost of those machines is somewhere between $1 [million] and $2 million. And you have to do a lot of scans to cover those costs.

At today's hearing, FDA scientists are expected to testify that their warnings about radiation risks from devices were ignored by the agency. Studies show that thousands of people die a year from radiation-induced cancer from these devices.

Jim Hitchin's company, SpectraScience, makes a device that detects colon cancer without using radiation. He says, though, it's not just doctors driving up the imaging tests -- ot's patients wanting answers.

Jim Hitchins: You know, we all want to live forever. At least most of us do.

The FDA hearing is part of a larger move by the agency to re-evaluate its approval process for all medical devices.

In Philadelphia, I'm Gregory Warner for Marketplace.

About the author

Gregory Warner is a senior reporter covering the economics and business of healthcare for the entire Marketplace portfolio.
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The burden of proof is on the proponent of overusing CT to PROVE that it DOES NOT cause cancer, not the other way around. Given that we have great historical data on radiation exposure and cancer (and CT utilizes ionizing radiation, which you know) it is clear that CT can cause cancer.
The key question is "Is there an overall benefit to the patient", i.e. is the risk of not being properly diagnosed higher than the risk of cancer induction.
For the majority of patients, it is. But it IS up to the Radiologist to have a good working knowledge of that risk, as well as to suggest alternative imaging modalities that have less risk than CT.
CT is neither helpful nor harmful on its own, it how we choose to use it in the best interests of our patients.

" Studies show that thousands of people die a year from radiation-induced cancers from these devices".
I am a radiologist of 40 years standing, and am still waiting to read an article proving that CT scans cause cancer.
If you have one please let me read it.
I thought that the incidence of cancer was decreasing, not increasing

Excellent commentary about the overuse of imaging. I believe this is a result of convenience, revenue, or lack of confidence in other diagnostic skills. Similar questions could be talked about with other imaging (including x-ray and MRI). I wish more questions were asked of chiropractors and podiatrists with imaging accessible in office and the overuse with patient care.

Christopher Anthony, D.C.
Tri-Synergy Chiropractic

Thank you for correcting your story about CT scanners. I work as an MRI tech at an imaging center in Maine. When I heard the story on the radio this morning, MRI machines were grouped with CT scanners as exposing people to dangerous radiation. In fact, people undergoing an MRI are exposed to radio waves (EM radiation that is not harmful because it is not strong enough to ionize, or break up the chemical bonds, of molecules in a person's body), as well as time-varying magnetic fields, the strength of which are regulated by a federal regulatory body. Neither the radio frequency pulses or time-varying magnetic fields used in clinical MRI have been demonstrated to pose any safety concerns to patients. I was surprised to hear such a glaring error in a story on NPR, but I am glad it was corrected promptly.

Technically true that Radiologists cannot directly engage in self referral. At times however, they can suggest in their reports certain followup intervals for repeat imaging, at the ultimate decretion of the referring physician. Secondly, Radiologists in Canada and the UK are indeed responsible for radiation dose to patients, and have the autonomy to refuse a scan or suggest alternate imaging/alternate workup for patient problems. In the States, not so much as Radiology is a business as much as anything -- if one Radiologist rightly refuses to perform a CT, another one will agree to do so as long as he/she gets paid. Its a shame.

A CT scan can deliver up to 100 times the radiation from a normal X-ray scan. “First do not harm”? Youbetcha.

Belief in the value of full body CT scans to detect disease in it’s early stages was an expression of the conviction that the broad application of information technology to health care would reduce health care costs without goring the oxen of vested interests such as insurers. It had the further advantage that it promised to help the IT industry recover from the dot com bust, which it still has yet to do. And it appealed to our faith in technology as a dues ex machina that would save us from ourselves without our having to change our beliefs or behaviors; a painless quick fix that boosted the economy and imposed no sacrifices. Who could resist?

It has taken so long for the FDA to get around to looking at this because the FDA represents the medical industry not the common good.

Wow! Thank you, Dr. Saba, for such a complete treatise. I was simply going to mention the fact that MRI uses no irradiation, so is not a health risk on that point. And then I find a ton more information that I never expected. Thank you, Dr.

Broadly speaking, there are two types of physicians involved in the use of CT scanners - Radiologists and non-Radiologists. The conflict of interest that you (and many others) have touched on - the fact that CT may be overutilized by physicians who have a financial interest in the CT scanner - is indeed very real and very problematic. The conflict of interest, however, exists only for the physicians who are non-Radiologists (for example, a Urologist who orders a CT scan of one of his own patients to be done on a CT scanner that he owns). To understand the complete story, one must also recognize that many CT scanners are owned by Radiologists. Radiologists are physicians whose specialty training (5 years of post-MD residency, often followed by 1 or 2 years of subspecialty fellowship) is in medical imaging. Radiologists do not order CT scans; they supervise and interpret the CT scans that other physicians order. In this way, the Radiologist has no ability to overutilize the technology, and therefore, for the Radiologist, there is no conflict of interest in owning the imaging equipment. Many non-Radiologists who own imaging equipment engage in the act of "self referral." The ACR (American College of Radiology) has fought long and hard to encourage legislation against this practice, however, we have been consistently outnumbered by the non-Radiologist physicians who have a financial interest in continuing the practice of self-referral (i.e. the AMA).
Overutilization of imaging is indeed a problem, but we must be careful not to throw the baby out with the bath water. The Radiologists are blameless in this arena, and should have a seat at the table in decisions regarding the utilization of medical imaging, as they do not control the flow of the patients. Furthermore, beyond training in the interpretaion and supervision of medical imaging, it is the Radiologist who has been uniquely trained in the full safety implications of imaging and the appropriate use of imaging, so that it is done most efficiently and effectively without redundancy or unnecessary studies.

Incidentally, the first sentence of your piece mentions MRI and CT, while the rest of piece focuses on radiation safety concersn. While overutilization of MRI is a financial concern, it is not a radiation safety concern. There is no ionizing radiation imparted to the patient in MRI. Indeed, this is one of the great advantages of MRI over CT.

Regarding the question below about contacting me in the future, I would greatly welcome that. Thanks for your great program. I'm a big fan.

Philip R. Saba, M.D.

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