X-rays and other medical scans could be playing a far bigger part in the spread of cancer than doctors had previously thought. New research has discovered that x-rays are causing cancer in cells that are not directly targeted.
The new study suggests that current estimates of cancers caused by radiation from medical tests are far too low, and that it may be a major carcinogen.
Italian researchers made the discovery while they were using x-ray radiation on mice. Neighbouring or 'bystander' cells were damaged, and became carcinogenic, through some kind of cell-to-cell communication or chemical signal.
In the experiment, 62 per cent of mice who had whole-body irradiation developed tumours and died after around 23 weeks compared with 39 per cent of mice that were irradiated while enclosed in a lead shield.
Mice that were given a gene that made them prone to brain tumours didn't develop cancer if they weren't irradiated.
(Source: Proceedings of the National Academy of Science USA, 2008; 105: 12445-12450).