Low-dose radiation poses small cancer risk: report
There is likely no such thing as a safe level of exposure to radiation, although cancer is rarely induced by low doses, a panel of U.S. scientists said Wednesday.
"The scientific research base shows that there is no threshold of exposure below which low levels of ionized radiation can be demonstrated to be harmless or beneficial," said Richard Monson, the panel's chair and a professor of epidemiology at Harvard's School of Public Health.
"The health risks – particularly the development of solid cancers in organs – rise proportionally with exposure."
The panel's report addresses amounts of radiation from medical treatments such as full-body CT scans. The findings are expected to affect government safety recommendations in the U.S.
A low dose of 100 millisieverts of radiation – the equivalent of 10 chest X-rays – is expected to cause solid cancer or leukemia in one out of 100 people over a lifetime, the report said. About half of those cases could be fatal.
The panel's report updates research based largely on survivors of the 1945 atomic bomb attacks in Japan.
While medical radiation is often appropriate, "exposure to any unnecessary radiation should be avoided," Monson told a news conference. "And what is unnecessary is up to an individual."
Natural sources of radiation such as gamma rays from space and radon in the environment account for about 82 per cent of our exposure, the report said.
More research is needed on those who receive frequent doses such as full-body CT scans, and on children who get X-rays or radiation treatment for cancer, the panel said.
Research on more than 400,000 nuclear industry workers found they had a 10 per cent higher risk of death from cancer, according to a related report released Wednesday by the International Agency for Research on Cancer in France.