Medical imaging has become a routine part of assessing health problems over the last few decades. But a new study reveals that children who undergo CT head scans triple their risk of developing leukemia or a brain tumour.
The research, published in the Lancet, looked into how the routine use of CT scans was linked to cancer risk. The scans, which go by the full names of Computed Tomography, use software to construct 3-D x-ray images, and are used to provide detailed structural visualisations of the human body.
The team, from Newcastle University, studied data from 180,000 children who underwent CT scans between 1985 and 2002. They found that youngsters who received two or three CT head scans before the age of 15 were three times more likely to develop brain cancer over the next decade, compared to the rest of the child population. Dr Mark Pearce, one of the researchers, explained to Telegraph:
"CT scans are very useful but they have relatively high doses of radiation, particularly when compared to x-ray. They have about 10 times the dose used in x-ray."
It's worth noting, however, that the radiation doses used in CT scans have dropped over time, so the potential risk is actually growing ever smaller, and that the risk is relative, so that the absolute number of extra cancer cases is in reality, small. It's also important to remember that the short-term benefits of CT scans typically far outweigh the long-term risk. The finding does, though, reinforce the idea that the scans should only ever be used when fully justified. [Lancet via The Telegraph]