Does radiation from X rays, CT scans really cause cancer?

Countless scientific studies have debated over the issue that radiation from X-rays, CT scans and other medical imaging causes cancer and now, a research has suggested that the belief is based on an unproven, decades-old theoretical model.

The model, known as linear no-threshold (LNT), is used to estimate cancer risks from low-dose radiation such as medical imaging. But risk estimates based on this model "are only theoretical and, as yet, have never been conclusively demonstrated by empirical evidence," corresponding author James Welsh and colleagues write. Use of the LNT model drives unfounded fears and "excessive expenditures on putative but unneeded and wasteful safety measures."

The LNT model dissuades many physicians from using appropriate imaging techniques and "discourages many in the public from getting proper and needed imaging, all in the name of avoiding any radiation exposure, the researchers wrote.

The authors reexamined the original studies, dating back more than 70 years, which led to adoption of the LNT model. This reappraisal found that the data reported in those studies do not actually support the LNT model.

Any claim that low-dose radiation from medical imaging procedures is known to cause cancer should be vigorously challenged, because it serves to alarm and perhaps harm, rather than educate, they noted.

The authors concluded that the LNT model should finally and decisively be abandoned.

The study is published in the American Journal of Clinical Oncology.