Children
more sensitive
to radiation
than adults, experts warn
Dr. Shireen Atabaki looks over a CT scan of a brain near the
emergency room at the Children's National Medical Center in
Washington.
ASSOCIATED PRESS
Oct. 28
A
toddler tumbles down stairs, a preschooler falls off a tricycle
or a teen gets clobbered in football, and its pretty likely the
emergency room will order a CT scan to make sure theyre OK. But
the majority of children with minor head injuries turn out to be
fine, meaning too many kids are needlessly exposed to the scans
radiation, say specialists developing new guidelines that aim to
cut by a third unnecessary CT scans of childrens brains.
Exposure is cumulative, and children are likely to need numerous CT
exams over the course of their lives that will add up.
CT
SCANS computer-enhanced X-rays that can provide a better view of
all parts of the body, not just the brain have revolutionized
medicine. But the scans, more popularly known as CAT scans, do emit
significantly more radiation than a standard X-ray, and children are
more sensitive to radiation than adults.
Yet with the number CT scans increasing sevenfold in the last
decade, up to 3 million a year now are being performed on U.S.
children. Theres little guidance on when theyre truly necessary or
when other exams will do.
So specialists have begun a nationwide effort to curb
unnecessary child CT scans and ensure that when one is needed,
hospitals use a child-appropriate radiation dose instead of the
higher adult dose too often used.
We dont want to scare
anybody, says Dr. Tom Slovis, chief of pediatric imaging at
Childrens Hospital of Michigan, who co-wrote an advisory explaining
child-sized doses that the National Cancer Institute and Society for
Pediatric Radiology mailed to 160,000 doctors in late summer.
CT is a wonderful test, it saves lives, he stresses. But
weve got to do it the right way.
Just because a procedures available doesnt mean its
necessary for your child, adds Dr. Shireen Atabaki of Childrens
National Medical Center in Washington, who led the new head-injury
research.
RADIATION RISKS
Radiation from a single CT scan still is relatively low and
certainly not high enough to warrant skipping a scan if a child may
be seriously ill or injured, such as after a car crash, specialists
warn. But recent research suggests lower radiation doses than once
thought as low as 10 to 20 REMs may somewhat increase peoples
risk of getting cancer decades later. Exposure is cumulative, and
children are likely to need numerous exams over the course of their
lives that will add up.
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Simply
adjusting the dose can lower childrens radiation absorption. For
example, a child given a typical adult-dose brain CT scan will
absorb 6 REMs of radiation, and 2 to 3 REMS for abdominal CT. Adjust
the scanner to a pediatric setting, and that child will absorb 3
REMS from a brain CT and 0.6 REMS to the abdomen. (A standard chest
X-ray, in contrast, provides about 0.01 REM.)
PRESSURE FROM PARENTS
When not to give a CT scan at all, however, is trickier.
About 2 percent of all childrens ER visits are for head
injuries. Major trauma definitely requires a CT scan, but Atabaki
noticed that doctors gave widely varied reasons for scanning kids
with minor injuries some merely cited pressure from worried
parents.
Together with three other hospitals Strong Memorial
Hospital in Rochester, N.Y., Hasbro Childrens Hospital in
Providence, R.I., New Yorks Mt. Sinai Hospital and Inova Fairfax
Hospital in suburban Washington she studied 1,000 patients.
CT scans found an intercranial injury in less than 7 percent
just 65 children.
Then Atabaki examined characteristics that predicted an
injury, and concluded CT scans are needed if children have any of
the following risk factors: is age 2 or younger; has a skull
fracture or deformity; has a bicycle-related injury; is dizzy, has a
behavior change or problems with vision or other senses; or scores
less than 15 on a standard neurological exam called the Glasgow Coma
Score.
More than two dozen other supposed risk factors didnt
predict who needed a CT scan, Atabaki told a recent meeting of the
American Academy of Pediatrics not even the very commonly cited
vomiting. Why? Vomiting is a symptom of concussion, but CT scans
cant diagnose concussion.
Several universities are planning a larger study to confirm
Atabakis guidelines. Doctors also are studying for other illnesses,
such as when ultrasound, which doesnt emit radiation, can be
substituted to diagnose appendicitis.
While that research continues, parents should ask doctors if
a CT scan is the best exam for their child and if the answer is
yes, then ask if the scanner will be adjusted to a child dose,
Slovis advises.
If they do it the way they do adults, thats probably not
the place you should be, he says.
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