Exposure to everyday sources of radiation, mostly medical X-rays, raises the risk of cancer but not by much and there is no clear line between a harmless dose and a disease-causing dose, an expert panel reported on Wednesday (June 29).
People should think twice about having unnecessary high-dose X-rays such as the full-body CAT scans being offered by some clinics, the panel advised, but otherwise should be reassured by the findings.
The report from the National Research Council updates 1990 findings based mostly on survivors of the 1945 atomic bomb attacks against Japan, about 45 percent of whom are still alive.
A low dose of about 100 millisieverts of radiation - the equivalent of 10 chest X-rays - can be expected to cause cancer in one out of every 100 people, the report finds.