Saturday Sept 17, 2016 (foodconsumer.org) -- Low dose ionizing radiation from diagnostic computed tomography (CT) scans increases risk of cancer, according to a study published in the MBJ.  (This is not the only study that reveals the ionizing radiation is a cancer-causing agent.  In fact, this type of radiation has already been recognized by the U.S. government and many other authoritative organizations as a carcinogen.)

For the study, researchers followed people who were exposed to diagnostic CT scans for 9.5 years and found their overall cancer risk was 24% higher than those who were not exposed to x-ray based CT scans.

The study also found high doses of radiation from CT scans was associated with higher risk of cancer, meaning that this was a positive association, and young people were more susceptible than older people.  The risk for cancer in those who were exposed to the CT scan radiation at the age of one to four years was increased by 36%.

In this study, exposure to the CT scans was found to increase risk for many types of solid cancer including cancers of digestive organs, melanoma, soft tissue cancer, female genital cancer, urinary tract cancer, brain cancer, and thyroid cancer, leukemia, myelodysplasia, and some other lymphoid cancers. 

The CT scans (the average effective radiation dose per scan was about 4.5 mSv) resulted in 9.38 cases of cancer per 100,000 person years.  The risk for cancer induced by the CT scan radiation increased as people became older. 

The researchers concluded that even though the radiation doses from CT scan used today were lower, the risk was still there.  They suggested that use of CT scans should be only  for people with known clinical conditions.  In other words, they should not be used as a screening tool or diagnostic tool.

It is a fact that there is no safe threshold for ionizing radiation or x-ray, meaning that any dose of radiation increases cancer risk. (David Liu)

John D Mathews,  Anna V Forsythe,  Zoe Brady,  Martin W Butler,  Stacy K Goergen,  Graham B Byrnes, Graham G Giles,  Anthony B Wallace, Philip R Anderson, Tenniel A Guiver,  Paul McGale,  Timothy M Cain,  James G Dowty, Adrian C Bickerstaffe, Sarah C Darby, Cancer risk in 680 000 people exposed to computed tomography scans in childhood or adolescence: data linkage study of 11 million Australians, BMJ 2013;346:f2360