CT scans of young people can cause significant increases in the risk of leukemia and brain cancer according to a new study published in a June edition of the British medical journal The Lancet.
       
CT or computed tomography scans involve dozens of X-rays from various angles and combine them to create complex images. Denise Grady of the New York Times said CT scans “much more radiation” than traditional X-rays, and Nancy Shute of National Public Radio said they use “far more.” Neither provided a comparison: but a CT scan of the abdomen and pelvis might give a 20 miliSievert dose, or seven times as much as an ordinary X-ray of the spine (1.5 mSv), and as much as 20,000 times the dose from an X-ray of an extremity (0.001 mSv). This, according to the Radiological Society of North America’s “patient safety program.”
       
The Times reported that “Children under 15 who had two or three scans of the head had triple the risk of brain cancer compared with the general population, the researchers found, and 5 to 10 scans tripled the risk of leukemia.”
       
Amy Berrington de Gonzalea of the National Cancer Institute, who helped conduct the new study, told NPR June 7, “We found that the radiation exposure from the CT scans was associated with a subsequent increased risk of both leukemia and brain tumors.”
       
Katie Moisse of ABC News online noted that the study considered more than 355,000 children and teens in Britain, while Denise Grady in the Times and Rob Stein at NPR said 180,000 British youths were studied between 1985 and 2002.
      
 David Brenner, of Columbia University’s Center for Radiological Research and lead author of a 2001 study estimating the cancer risk from CT scans, told ABC News. “There was debate about whether the risks were real, and this study shows pretty unequivocally that they are.”
      
 “All medical procedures have risks and benefits,” Brenner told ABC. “That said, there are situations where CT scans are being used too much.” He estimates, ABC News reported,   that 20 percent of the country’s 80 million CT scans each year (16 million) are either unnecessary or could be replaced.
 

Radiologists Recommend
Questionable Scans
 
        The American College of Radiology was quick to issue a statement regarding the findings and urged parents not to refuse “needed” CT scans, emphasizing especially serious injuries like those to the head and spine.
       
However, last year the use of CT scans to diagnose head injuries in children was called into question by a study noted in the journal Pediatrics. NPR reported the head CT scans “may needlessly expose [children] to radiation.” Furthermore, NPR noted, “the scans also don’t catch minor injuries any better than observing the child.”
       
Lise Nigrovicof, Children’s Hospital Boston who led the Pediatrics study, told NPR that she’s hoping doctors and parents will remember that CT scans aren’t always necessary, particularly since they cannot diagnose concussion.
      
 Just a month prior to the June Lancet report, the Food and Drug Administration issued an order to CT Scan makers telling them “Make sure your new equipment has settings and instructions that minimize radiation hazards for kids, or the agency will look to slap a label on the machines that recommends they not be used for children at all,” NPR reported May 9, 2012. [“FDA Leans On Device Makers to Cut X-Ray Doses For Kids”]
     
Co-author Berrington de Gonzalea of the NCI had an additional warning to make. Research shows that scans of other parts of the body also seem risky: “There’s a good chance that even one CT scan poses some risk to children — as well as adults — and possibly for all sorts of cancers,” she told ABC News.
 

Parents Must Ask A
bout Alternatives
 
        Moms and dad should ask their doctors if a recommended CT scan is really essential, or if it can be replaced with safer tests like ultrasound or magnetic resonance imaging (MRI), which don’t dose your kid with radiation.
      
 The June Lancet report online is titled “Radiation exposure from CT scans in childhood and subsequent risk of leukaemia and brain tumours: a retrospective cohort study.” See: <www.thelancet.com/journals/lancet/article/PIIS0140-6736(12)60815-0/abstract>
 
— John LaForge is on the staff of Nukewatch, a radiation and weapons watchdog group in Wisconsin.