Diagnostic X-rays are the largest man made source of radiation exposure to the general population. Although there are many benefits to these X-rays, it's also believed exposure during the test is responsible for a small number of cancers. A new study attempts to calculate the risk of cancer from exposure to diagnostic X-rays.
Researchers at the University of Oxford and Cancer Research in the United Kingdom conducted the study. The investigators estimated the likely extent of the cancer risk based on the annual number of diagnostic X-rays undertaken in the United Kingdom and in 14 additional developed countries.
Investigators report the cumulative risk of cancer ranged from 0.6 percent to 1.8 percent to over 3 percent in Japan. Japan has the highest number of annual diagnostic X-rays in the world. In the United Kingdom, researchers say the risk of cancer was 0.6 percent. This suggests around 700 of the 124,000 cases of cancer diagnosed in the United Kingdom each year could be attributable to exposure to diagnostic X-rays.
Researchers say their calculations depended on a number of assumptions, and so are inevitably subject to considerate uncertainty.
However researchers from Germany say the present study has not taken into account the benefit of the X-rays for the patients in their research. They say the earlier detection of cancer by radiological examinations and possibly earlier treatment could mean more cancers are cured. However, they agree that a general goal should be to avoid unnecessary X-ray procedures. For example, they point out that up to 30 percent of chest X-rays may not be necessary and doctors need to think carefully about the benefits for and the risk to their patients for each examination.