X-rays can cause childhood leukemia | 06Dez2010 15:41:42
New findings by researchers from the University of California, Berkeley, School of Public Health reveal that X-rays can significantly increase children's risk of developing leukemia. Having even one X-ray, they say, can moderately increase the risk of developing certain kinds of leukemia, calling into question the overall safety of X-rays.
Discovered as part of the Northern California Childhood Leukemia Study (NCCLS), a population-based case-control study taking place in 35 counties in California, the findings shed new light on how continual exposure to even low-dose radiation can spur the development of harmful cancers. Previously, most experts just assumed that X-rays were fairly safe.
"The general clinical impression has been that the level of radiation a child would be exposed to today from a conventional X-rays would not confer an additional risk for cancer," said Patricia Buffler, professor of epidemiology at UC Berkeley and principal investigator of the NCCLS. "The results of our study were not what we expected."
According to scientific studies, humans are exposed to ionizing radiation -- the kind responsible for DNA mutations and cell damage -- all the time, including from natural sources like ground soil and the air itself. But the daily rate of environmental exposure to such ionizing radiation is roughly one-tenth of the amount emitted by a single X-ray, so it is much less threatening.
Even worse, modern computed tomography (CT) scans emit hundreds of times more ionizing radiation than X-rays do, and many people receive CT scans all the time without any awareness of their dangers.
"If even plain film X-rays are associated with an increased risk of leukemia, then one has to wonder about CT scans, some of which can generate 500 times the dose of radiation of an X-ray," commented Dr. Rebecca Smith-Bindman, a UC San Francisco radiologist not associated with the study.
According to Dr. Smith-Bindman, X-rays account for two-thirds of the imaging procedures children undergo. Twenty percent of their overall exposure to radiation comes from X-rays, while another ten percent comes from CT scans.
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October 06, 2010 by: Jonathan Benson, staff writer