[NukeNet] Use of CT Scans, Cancer Risk Rise

[Mike Ewall]

 From the newsletter of the Breast Cancer Fund (www.breastcancerfund.org)

Use of CT Scans, Cancer Risk Rise

Only months after a study showed that radiation from a 
high-resolution cardiac CT scan may put women and young people at 
greater risk of developing breast and lung cancer, a new study warns 
that the rise in use of CT scans is needlessly raising the cancer 
risks of millions of Americans. The study’s authors say that as 
many as 2 percent of all cancers in the U.S. might be due to 
radiation from administered CT scans.

Computed tomography, or CT, scans are a source of ionizing 
radiation—the best- and longest-establishedd environmental cause of 
breast cancer. There is no such thing as a safe dose of radiation and 
the risk accumulates over a lifetime. The authors say patients and 
doctors should talk openly about the radiation risks before having a CT scan.

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Governor Schwarzenegger Signs Radiation Safety Bill into Law

On September 30, 2005, California Governor Arnold Schwarzenegger 
signed the Radiation Safety Act, AB 929, into law. This new law 
requires that all radiologic equipment will be subject to quality 
assurance standards and tests­making all forms of radiation, 
including X-rays, CT scans and mammograms­safer for California patients.

Exposure to ionizing radiation is the longest- and best-established 
environmental cause of human breast cancer, and radiation damage to 
genes is cumulative over a lifetime. Radiation is both a mutagen 
(causing genetic mutation) and a carcinogen (causing cancer). There 
is no safe dose of radiation and, over time, multiple exposures to 
low-dose radiation may cause the same harm as a single exposure.

While diagnostic radiation and radiation treatment are extremely 
valuable in the practice of medicine and dentistry today, it is 
important to make sure that patients receive the lowest possible dose 
of radiation without compromising image quality.

Assembly Bill 929, authored by Assembly Member Jenny Oropeza 
(D-Carson), and co-sponsored by the Breast Cancer Fund and the 
National Brain Tumor Foundation, requires the California Department 
of Health Services to develop mandatory quality assurance standards 
and tests for all radiation emitting medical and dental equipment in the state.

AB 929 is an important step to protecting patients from unnecessary 
exposure to a known carcinogen and, ultimately, preventing breast cancer.

Read the complete bill text:
http://www.leginfo.ca.gov/pub/05-06/bill/asm/ab_0901-0950/ab_929_bill_20050930_chaptered.html

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http://www.time.com/time/health/article/0%2C8599%2C1689045%2C00.html?msource=news1207&tr=y&auid=3245756

Study: CT Scans Raise Cancer Risk

Thursday, Nov. 29, 2007 By MARILYNN MARCHIONE/AP

Millions of Americans, especially children, are needlessly getting 
dangerous radiation from "super X-rays" that raise the risk of cancer 
and are increasingly used to diagnose medical problems, a new report warns.

In a few decades, as many as 2 percent of all cancers in the United 
States might be due to radiation from CT scans given now, according 
to the authors of the report.

Some experts say that estimate is overly alarming. But they agree 
with the need to curb these tests particularly in children, who are 
more susceptible to radiation and more likely to develop cancer from it.

"There are some serious concerns about the methodology used," but the 
authors "have brought to attention some real serious potential public 
health issues," said Dr. Arl Van Moore, head of the American College 
of Radiology's board of chancellors.

The risk from a single CT, or computed tomography, scan to an 
individual is small. But "we are very concerned about the built-up 
public health risk over a long period of time," said Eric J. Hall, 
who wrote the report with fellow Columbia University medical 
physicist David J. Brenner.

It was published in Thursday's New England Journal of Medicine and 
paid for by federal grants.

The average American's total radiation exposure has nearly doubled 
since 1980, largely because of CT scans. Medical radiation now 
accounts for more than half of the population's total exposure; it 
used to be just one-sixth, and the top source was the normal 
background rate in the environment, from things like radon in soil 
and cosmic energy from the sun.

A previous study by the same scientists in 2001 led the federal Food 
and Drug Administration to recommend ways to limit scans and risks in children.

But CT use continued to soar. About 62 million scans were done in the 
U.S. last year, up from 3 million in 1980. More than 4 million were 
in children.

Since previous studies suggest that a third of all diagnostic tests 
are unnecessary, that means that 20 million adults and more than 1 
million children getting CT scans are needlessly being put at risk, 
Brenner and Hall write.

Ultrasound and MRI, or magnetic resonance imaging, scans often are 
safer options that do not expose people to radiation, they contend.

CT scans became popular because they offer a quick, relatively cheap 
and painless way to get 3D pictures so detailed they give an almost 
surgical view into the body. Doctors use them to evaluate trauma, 
belly pain, seizures, chronic headaches, kidney stones and other 
woes, especially in busy emergency rooms. In kids, they are used to 
diagnose or rule out appendicitis.

But they put out a lot of radiation. A CT scan of the chest involves 
10 to 15 millisieverts (a measure of dose) versus 0.01 to 0.15 for a 
regular chest X-ray, 3 for a mammogram and a mere 0.005 for a dental X-ray.

The dose depends on the type of machine and the person ­ obese people 
require more radiation than slim ones ­ and the risk accumulates over 
a lifetime.

"Medical care in this country is naturally so fragmented. Any one 
doctor is not going to be aware of the fact that a particular patient 
has had three or four CT scans at some point in the past," said Dr. 
Michael Lauer, prevention chief at the National Heart, Lung and Blood 
Institute.

People with chronic problems like kidney stones are likely to get too 
many scans, said Dr. Fred Mettler, radiology chief in the New Mexico 
Veterans Administration health care system.

"I've seen people who are 30 years old who have had at least 18 scans 
done," he said.

That puts them at risk of developing radiation-induced cancer, 
Brenner and Hall said. They base this on studies of thousands of 
Japanese atomic bomb survivors who had excess cancer risk after 
exposures of 50 to 150 millisieverts ­ the equivalent of several big CT scans.

"That's very controversial. There's a large portion of the medical 
physics community that would disagree with that" comparison, said 
Richard Morin, a medical physicist at the Mayo Clinic in 
Jacksonville, Fla. However, others defended the data, which has been 
widely cited in other radiation studies.

"It's the best evidence we've got" on cancer risks, Lauer said.

Dr. Robert Smith, the American Cancer Society's director of 
screening, said the authors' estimate that 2 percent of future 
cancers may be due to CT scans "seems high." But since cancers take 
10 to 20 years to develop, "the ability to even observe that kind of 
an increase is going to be very difficult," he said.

The authors stressed that they were not trying to scare people who 
need CT scans away from having them. In most cases, the benefits 
exceed the risks, especially for diagnostic scans.

However, using the scans to screen people with no symptoms of illness 
­ like screening smokers for signs of lung cancer ­ has not been 
shown to save lives and is not currently recommended.

Many groups also condemn whole-body scans, often peddled by private 
practitioners in shopping centers as peace of mind to the worried 
well. Many of these centers are not accredited by the College of 
Radiology; only a third of all places that do CT scans in the U.S. 
are, although insurers are starting to require it for reimbursement, 
Moore said.

Many CT centers also are set up for adults and rarely image children, 
who need adjustments to limit dose and radiation risk, said Dr. Alan 
Brody, a radiologist at Cincinnati Children's Hospital Medical Center 
who wrote a report on the topic. He said parents should seek a center 
that often handles children.

Both doctors and patients need to be more aware of radiation risks 
and discuss them openly, Brenner and Hall said.

"We were astonished to find, when we were researching materials for 
this paper, how many doctors, particularly emergency room physicians, 
really had no idea of the magnitude of the doses or the potential 
risks that were involved," Hall said.

Other studies found the opposite problem: Three out of 10 parents in 
one study insisted on CT scans instead of observing the child's 
condition for awhile even after they were told of the radiation risk, 
Brody said.

"This is what our patients want," and they expect fast answers from 
doctors, he said.

The pressure is greatest for ER doctors who "are in a bind ... they 
have all these patients stacked up" and need to make quick decisions, 
Mettler said.

Future generations of devices using less radiation should help 
alleviate the concern, but these mostly are directed at the emerging 
field of heart scans, Lauer said.

"When we order a CT scan it just doesn't seem like such a big deal" 
but it should be, he said. "The threshold for ordering these tests is 
low and it's getting lower and lower over time, which means that the 
risks become potentially all that more important."


Mike Ewall
Energy Justice Network
215-743-4884
catalyst at actionpa.org
http://www.energyjustice.net