A new study suggests that computed tomography (CT) scans, commonly used in medical imaging, may increase the risk of brain tumors.
The use of CT scans has increased dramatically over the last two decades.
CT scans greatly improve diagnostic capabilities (which improve clinical outcomes) but they deliver higher radiation doses than other tests.
Therefore, radiation protection is a concern, especially among children, who may receive higher radiation doses.
The most common harms caused by radioactivity among children and young adults are leukemia and brain tumors.
In the current study, researchers evaluated leukemia and brain tumor risks following exposure to radiation from CT scans in childhood.
The researchers analyzed data from a nationwide group of 168,394 Dutch children who received one or more CT scans between 1979 and 2012.
They also surveyed all Dutch hospital-based radiology departments to ascertain eligibility and participation. In the Netherlands, pediatric CT scans are only performed in hospitals.
Overall cancer incidence was 1.5 times higher than expected.
For all brain tumors combined, and for malignant and nonmalignant brain tumors separately, the team found there were links between radiation dose and brain cancer.
The risks increased to between two and four for the highest dose category. No such association was found for leukemia. Radiation doses to the bone marrow, where leukemia originates, were low.
The researchers caution that this pattern of higher cancer risk may be partly due to confounding factors, because the incidence of brain tumors was higher in the cohort than in the general population.
CT scans are sometimes used to identify conditions associated with an increased tumor risk; the reason these children had CT scans may be linked to their risk of developing cancer.
The study is published in the Journal of the National Cancer Institute.
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