CAT Scans Worries Mount Over...

[Harrison]

Worries Mount Over Excessive CAT Scans

Concerned About Radiation, More Doctors Seek Curbs; 341 Scans in 18 Months

By HEATHER WON TESORIERO
November 2, 2006; Page D1

When Molly Birnbaum was struck by a car in Boston last summer, she was taken to the emergency room and, as is typical of trauma care, given a CT scan to look for injuries. Ms. Birnbaum, 23 years old, was scanned over and over, nine times in a week, until her father -- outraged and alarmed -- ordered the doctors to stop.

Ms. Birnbaum's father might seem like an unlikely foe of such scans -- he's a radiologist. But in recent years, Dr. Birnbaum had grown increasingly concerned about patients getting exposed to excessive amounts of radiation from CT scans, which generally emit significantly larger doses of radiation than traditional X-rays.
[CAT scans]
An image of a human heart created by a CAT scan, an increasingly popular diagnostic tool

His daughter's experience spurred him to action. Now Dr. Birnbaum is part of a growing number of medical professionals, managed-care companies and scanner manufacturers that are trying to rein in CT scanning out of concerns over excessive radiation, which is known to increase the risk of cancer.

There's been an explosion in CT scanning in recent years. Scans increased by nearly 50% between 2000 and 2003, when they hit 57 million. The rise comes from rapidly advancing CT technology that gives doctors better, more-detailed information to work with, making the scan widely viewed as one of the most valuable diagnostic tools in the field. What's more, the test is noninvasive and typically doesn't cost anything for insured patients. The test has also become popular as a means for patients to get full-body scans as a check-up.

There haven't been any studies that directly examined whether people who had multiple CT scans went on to develop cancer. But as the number of CT scans has climbed, some doctors have started to take notice of individual patients who have received multiple scans that place their total radiation doses at levels near or beyond those of some survivors of the nuclear attacks on Japan in World War II. Residents of Hiroshima and Nagasaki received a mean dosage of 20 millisieverts, a measurement of radiation exposure, although the bomb survivors received all the radiation at once, which is thought to be riskier, and the type of radiation was different from the X-rays used in modern medical scans. According to a managed-care database, one patient received 341 CT scans over an 18-month period, bringing the radiation exposure to 992.24 millisieverts. Several other patients received more than 100 CT scans.

Now, a range of players in the field are moving to prevent runaway CT scanning, including a large managed-care organization and the nation's largest diagnostics-benefits manager. And General Electric Healthcare has come out with a device that reduces radiation during cardiac CT scans by as much as 70%. "Obviously, the concern is the increased risk related to cancer," says Arl Van Moore, chairman of the American College of Radiology, which is also looking at the issue. Dr. Moore recently appointed an ACR task force to examine the issue of radiation exposure from diagnostic imaging. The group's report and position statement based on its findings is expected to come out next year.
[Radiation by the Numbers]

Invented in the 1970s, computed axial tomography scans (called CAT or CT scans) use special X-ray machines to take images of the body from multiple angles and can show various types of tissue with detailed precision. But unlike other kinds of advanced images, such as MRIs and ultrasounds, CT scans take pictures using ionizing radiation.

A full-body CT scan measures an estimated 12 millisieverts to 25 millisieverts. A mammogram measures about .84 millisieverts. Americans get about 3.6 millisieverts a year from natural sources. A 10-millisievert level is associated with an increased risk of cancer, though health experts debate whether a one-time dose carries different risks from those of cumulative exposure.

Children are at the greatest risk for long-term health problems from radiation because of the damage it wreaks on developing cells. In 2001, the Food and Drug Administration put out a notice to health-care professionals emphasizing the need to try to minimize radiation exposure in pediatric patients.

Not everyone in the medical community is embracing the cause. Some feel the risks aren't well-established and that the concern could dissuade patients from getting necessary tests. Reuben Mezrich, professor and chairman at the University of Maryland School of Medicine's Department of Radiology, casts a skeptical eye on the issue, saying there haven't been enough good studies on the risks. He also isn't convinced that radiation accumulates over time, noting that "we're always getting radiated."

Still, the nation's largest diagnostics benefit manager, National Imaging Associates Inc./Magellan Health, is taking steps to rein in CT scanning. In August, NIA started a new procedure with 30 of its clients to flag excessively scanned patients. NIA alerts their doctors and initiates discussions to see if there are other diagnostic options. Also, doctors who call insurance companies for pre-authorizations of patients deemed excessively scanned will need to talk to NIA first.

Company vice president and founder Thomas Dehn, a radiologist, says that the company started developing the program after seeing radiation-exposure levels that were 1,000% higher than medical guidelines, which Dr. Dehn calls "extraordinary, inappropriate and alarming."

A move away from CT scans won't necessarily save money. A reduction in overall scanning would save payers on insurance costs. But doctors could instead shift to other technologies such as MRIs, which don't emit ionizing radiation but actually cost more than CT scans.

Anthem Blue Cross and Blue Shield, a division of WellPoint Inc. for Maine, New Hampshire and Connecticut, has made curbing repetitive CT scanning for patients under 40 years old one of its top patient-safety initiatives. The insurer started looking at the issue at the urging of Dr. Birnbaum, who has a radiology practice in New Hampshire and sits on Anthem's diagnostic-imaging committee.

Anthem's medical director, Elizabeth Malko, says she didn't need much persuading on the issue, since she'd run into instances where she felt the technology was often used in place of clinical judgment or a physical exam. "I think we've all been convinced this is a fabulous technology. What hasn't been out there as much has been the info about radiation risk."

Anthem has committed to a three-phase program in its efforts to reduce excessive radiation. The first component is educational: The company has identified influential radiologists in various communities in New England and deploys Dr. Birnbaum to give them a presentation. Anthem has also assembled a tool kit for hospitals, radiologists and ordering physicians that explains the radiation dosage levels associated with various CT scans and how those increase risk. The kit is meant to guide clinicians in building internal programs for radiation safety.

The insurer also is planning to notify doctors who are ordering a scan if their patient has been identified as being repeatedly scanned. It also will send letters to doctors whose patients have had multiple CT scans in the past and encourage them to consider a radiology consultation to explore other imaging options. And Dr. Malko hopes that Anthem will be able to share the program with the larger community, which she says is important given that patients often switch insurers, sometimes several times, in their lifetime.

Though the notion of minimizing radiation exposure is built into radiology training -- physicians are taught to order scans "as low as reasonably achievable" -- getting physicians to actually curb CT scans has proven to be a tough challenge. Doctors like having as much diagnostic information as possible, and as new and more advanced technologies in scanning emerge, doctors like to put them to use. Dr. Birnbaum says that some physicians he's spoken to have expressed concerns that flagging the issue with primary-care practices could be bad for business.

But radiologists also admit that radiation dangers are often lost or forgotten in the field. "Unfortunately, there are many obstacles to getting people to reduce use of CT, and one of the prime ones is that everyone is willing to blame someone else," says Howard Forman, professor of radiology and public health at Yale Medical School. "Radiologists say it's the clinicians, clinicians say that radiologists are responsible. Patients are just purely uninformed."

Courtesy of WSJ; URL for this article (subs. req.):
http://online.wsj.com/article/SB116243449214110976.html

[Harrison]

I posted this original article three years ago. Perhaps some of you have read the latest news reports about renewed concerns about CT scans presenting an increased risk for cancer -- it was all over the news the past few days. WSJ did a good job on these stories -- thanks Shirley.

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CT Scans Linked to Cancer
Study Warns Radiation Dose From Single Test Can Trigger Disease in Some People

The risk of cancer associated with popular CT scans appears to be greater than previously believed, according to two new studies published Monday in the Archives of Internal Medicine.

The findings support caution against the overuse of CT scans and other medical technologies that use radiation. The studies also bolstered the rationale behind controversial new breast-cancer screening guidelines, which pushed back the recommended age for annual mammograms to 50 from 40. Mammograms also use radiation, but in smaller doses.

See full article with data tables:

http://online.wsj.com/article/SB126082398582691047.html

[Harrison]

CT-scan radiation exposure may be higher than earlier reported

1st on the web (December 16, 2009)

The use of CT scans has increased dramatically, and recently published studies indicate that the amount of radiation exposure may be greater than earlier reported, which may result in an increase in the number of radiation-related cancer cases and cancer-related mortality.

Two studies, published in the Archives of Internal Medicine, attempted to quantify the effect of CT on cancer incidence and mortality.

“Every day, more than 19,500 CT scans are performed in the United States, subjecting each patient to the equivalent of 30 to 442 chest radiographs per scan,” Rita Redberg, MD, a professor of medicine and director of the women’s cardiovascular services, at the University of California, San Francisco (UCSF) Medical Center, wrote in an accompanying editorial. “What is becoming clear [is] that the large doses of radiation from such scans will translate, statistically, into additional cancers,” she wrote.

Radiation doses

The first study, conducted by Rebecca Smith-Bindman, MD, of UCSF, and colleagues, was a retrospective cross-sectional investigation examining the radiation doses used with the 11 most common types of diagnostic CT scans. They examined data for 1,119 consecutive adults at four centers in the San Francisco Bay area between January and May 2008.

They found a mean 13-fold variation between the highest radiation dose and the lowest for each type of CT scan. Although the radiation exposure in some procedures was as low as 2mSv, the dose increased to 31mSv for a multiphase abdomen and pelvis CT scan.

“Even the median doses are four times higher than they are supposed to be, according to the currently quoted radiation dose for these tests,” Redberg wrote in her editorial. “Just one CT coronary angiogram, on average, delivers the equivalent of 309 chest radiographs. By their calculations, one in every 270 40-year-old women undergoing CT coronary angiogram will develop cancer from the procedure.” This is compared to one in every 8,100 women of the same age who had a routine head CT scan.

Radiation-related cancers

In the second study, Amy Berrington de González, PhD, an adjunct assistant professor at Johns Hopkins Bloomberg School of Public Health, and colleagues constructed a risk model to estimate age-specific cancer risk for each CT scan type. They derived data from the National Research Council’s report, “Biological Effects of Ionizing Radiation,” national surveys and insurance claims.

They found that approximately 29,000 future cases of cancer could be due to CT scans that took place in 2007. Abdomen, pelvis, chest, head and CT angiography were the largest contributors to this risk.
About 35% of these cancers were estimated to be from CT scans performed on people when they were 35 to 54 years-old. Lung cancer was estimated to be the most common radiation-related cancer, followed by colon cancer and leukemia.

“Presumably, as the number of CT scans increases from the 2007 rate, the number of excess cancers also will increase,” Redberg wrote. “In light of these data, physicians and their patients cannot be complacent about the hazards of radiation or we risk creating a public health time bomb.”

References:

Berrington de González A, Mahesh M, Kim KP, et al. Arch Intern Med. 2009;169 (22): 2071-2077.
Redberg R. Arch Intern Med. 2009;169 (22):2049-2050.
Smith-Bindman R, Lipson J, Marcus R, et al. Arch Intern Med. 2009;169 (22): 2078-2086.

Courtesy of: http://www.orthosupersite.com/view.asp?rid=59362