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Americans get most radiation from medical scans

By MARILYNN MARCHIONE, AP Medical Writer Marilynn Marchione, Ap Medical Writer

Mon Jun 14, 10:59 am ET

We fret about airport scanners, power lines, cell phones and even microwaves.

It's true that we get too much radiation. But it's not from those sources

it's from too many medical tests.

Americans get the most medical radiation in the world, even more than folks in

other rich countries. The U.S. accounts for half of the most advanced

procedures that use radiation, and the average American's dose has grown

sixfold over the last couple of decades.

Too much radiation raises the risk of cancer. That risk is growing because

people in everyday situations are getting imaging tests far too often. Like the

New Hampshire teen who was about to get a CT scan to check for kidney stones

until a radiologist, Dr. Steven Birnbaum, discovered he'd already had 14 of

these powerful X-rays for previous episodes. Adding up the total dose, "I was

horrified" at the cancer risk it posed, Birnbaum said.

After his own daughter, Molly, was given too many scans following a car

accident, Birnbaum took action: He asked the two hospitals where he works to

watch for any patients who had had 10 or more CT scans, or patients under 40

who had had five clearly dangerous amounts. They found 50 people over a

three-year period, including a young woman with 31 abdominal scans.

When other radiologists tell him they've never found such a case, Birnbaum

replies: "That tells me you haven't looked."

Of the many ways Americans are overtested and overtreated, imaging is one of

the most common and insidious. CT scans "super X-rays" that give fast,

extremely detailed images have soared in use over the last decade, often

replacing tests that don't require radiation, such as ultrasound and MRI, or

magnetic resonance imaging.

Radiation is a hidden danger you don't feel it when you get it, and any

damage usually doesn't show up for years. Taken individually, tests that use

radiation pose little risk. Over time, though, the dose accumulates.

Doctors don't keep track of radiation given their patients they order a test,

not a dose. Except for mammograms, there are no federal rules on radiation

dose. Children and young women, who are most vulnerable to radiation harm,

sometimes get too much at busy imaging centers that don't adjust doses for each

patient's size.

That may soon change. In interviews with The Associated Press, U.S. Food and

Drug Administration officials described steps in the works, including possibly

requiring device makers to print the radiation dose on each X-ray or other

image so patients and doctors can see how much was given.

The FDA also is pushing industry and doctors to set standard doses for common

tests such as CT scans.

"We are considering requirements and guidelines for record-keeping of dose and

other technical parameters of the imaging exam," said Sean Boyd, chief of the

FDA's diagnostic devices branch.

A near-term goal: developing a "radiation medical record" to track dose from

cradle to grave.

"One of the ways we could improve care is if we had a running sort of Geiger

counter" that a doctor checked before ordering a test, said Dr. Prashant Kaul

of Duke University.

He led an eye-opening study that found that U.S. heart attack patients get the

radiation equivalent of 850 chest X-rays over the first few days they are in

the hospital much of it for repeat tests that may not have been needed.

How much radiation is risky?

It's hard to say. The best guess is based on the 1986 Chernobyl nuclear power

plant accident and studies of Japanese atomic bomb survivors who had excess

cancer risk after exposures of 50 to 150 millisieverts (a measure of dose) of

radiation.

A chest or abdominal CT scan involves 10 to 20 millisieverts, versus 0.01 to

0.1 for an ordinary chest X-ray, less than 1 for a mammogram, and as little as

0.005 for a dental X-ray. Natural radiation from the sun and soil accounts for

about 2 millisieverts a year.

A big study last year estimated that 4 million Americans get more than 20

millisieverts a year from medical imaging. Two percent of people in the study

had high exposure 20 to 50 millisieverts.

Another study by Columbia University researchers, published in 2007, estimated

that in a few decades, as many as 2 percent of all cancers in the U.S. might be

due to radiation from CT scans given now. Since previous studies suggest that a

third of all tests are unnecessary, 20 million adults and more than 1 million

children are needlessly being put at risk, they concluded.

Just because a scan didn't find anything wrong doesn't mean a test wasn't

needed. Scans are useful for many diagnoses. But many studies suggest people

are getting too much imaging now. For example, Mayo Clinic researchers reviewed

the medical records of 251 people given heart scans in 2007 and found that only

a quarter of them were clearly appropriate.

Reasons for overuse:

_Accuracy and ease of use. Scans have become a crutch for doctors afraid of

using exams and judgment to make a diagnosis. Some think a picture tells more

than it does. Imaging that shows arthritis in a knee or back problems doesn't

reveal how to make it better, said Dr. Richard Baron, a primary care doctor in

Philadelphia.

"Physical therapy for an orthopedic injury is always the first choice," yet

doctors rush to order tests, he said. "The question you should be asking when

you do sophisticated imaging is, 'Is there something I can fix with an

operation?'"

_Malpractice fear. A missed heart attack or a burst appendix could be

devastating for a patient and mean a lawsuit.

"I have great sympathy for the ER physicians because of the responsibility

placed in their hands with strangers that come in off the street," said Louis

Wagner, chief physicist at the University of Texas in Houston. "They have to

make a decision that could mean life or death for a patient, and the fastest

way to find out is CT."

_Patient pressure. People urge doctors to "do something" to figure out what's

wrong, and "often, doctors feel that the way to demonstrate that they're doing

something is to order tests," said Dr. Christopher Cassady, a radiologist at

Texas Childrens Hospital and the American Academy of Pediatrics' expert on this

topic.

At his hospital, doctors first do an ultrasound on suspected appendicitis cases

instead of rushing into a CT scan. Ultrasounds require no radiation.

_Health care chaos. One doctor may not know that another has ordered the same

test. If a patient is referred to a specialist, "it's often easier for him to

order another study than to figure out how to get the one that was done

somewhere else," Baron said.

_Insurance issues. X-rays often are required by insurers to prove health, or

for students to study abroad.

_Availability. Rural hospitals may not have an ultrasound technologist on duty

in the wee hours, but imaging machines are always there.

_Treatment choice. A quick fix for chest pain artery-opening angioplasty

requires far more imaging and radiation than bypass surgery does. The same is

true of "virtual colonoscopy" instead of the standard version.

Which tests are overused? A scientific group, the International Commission on

Radiological Protection, cites routine chest X-rays when people are admitted to

a hospital or before surgery; imaging tests on car crash victims who don't show

signs of head or abdominal injuries; and low-back X-rays in older people with

degenerative, but stable, spine conditions.

Even when tests are justified, they often include more views than needed and

too much radiation. Top offender: chest CT scans looking for clogged arteries

and heart problems. Cardiologists are increasingly aware of this risk and are

seeking solutions.

At Columbia University, a study on dummies by Dr. Andrew Jeffrey Einstein found

two dose-modifying techniques could lower the needed radiation dose by 90

percent without harming image quality.

Another cardiologist and radiation safety expert, Dr. Gilbert Raff, showed the

same in real life. A study he led of nearly 5,000 patients at 15 imaging

centers in Michigan found that radiation dose could be cut by two-thirds with

no loss of quality.

What should patients do?

"You should question everything what's the dose, why am I getting it? You

should be an informed consumer," said Dr. Fred Mettler, radiology chief in the

New Mexico Veterans Administration health care system. He led a study of health

effects after the Chernobyl accident and is a U.S. representative to the United

Nations on radiation safety.

He advised challenging "big ticket" tests like CT scans that deliver a lot of

radiation to the chest and abdomen places where cancer is likely to develop.

"You shouldn't get too excited about feet and knee X-rays," Mettler said.

Questions to ask about radiation scans:

_Is it truly needed? How will it change my care?

_Have you or another doctor done this test on me before?

_Are there alternatives like ultrasound or MRI?

_How many scans will be done? Could one or two be enough?

_Will the dose be adjusted for my gender, age and size? Will lead shields be

used to keep radiation away from places it can do harm?

_Do you have a financial stake in the machines that will be used?

_Can I have a copy of the image and information on the dose?

Mettler suggests bringing a blank CD or thumb drive with you.

"You should have all of your stuff digitally on something," he said. "I keep

mine on my laptop."