An update on current epidemiology studies of leukaemia risks associated with CT scans

*Mark S. Pearce, Newcastle University 

Keywords: CT scans, epidemiology, ionising radiation, leukaemia

Epidemiology studies are invaluable for radiation protection purposes . While risk models are very useful and often relatively quick to calculate, they are better when complemented by the results of studies that directly observe health effects of radiation exposures in the populations radiation protection is aimed at. Of all medical radiation exposures, the one of growing interest from both a radiation research and public health perspective relates to the use of CT scans which are available worldwide at over 300,000 centres, with the number of machines continuing to increase. Whilst benefits to patients in most settings of having a CT scan can be substantial, concerns have been raised over the relatively high radiation doses associated with CT (for example, the dose to the stomach is around 50 times higher from an abdominal CT compared with that from an abdominal X-ray), particularly in terms of potentially increased future risks of cancer. The patient group of most concern are children, who are more susceptible to the effects of radiation, in part due to their longer post-irradiation life expectancy, and because following the same radiation dose they experience greater radiation-induced tissue damage than adults. Children are also known to receive higher radiation doses than necessary when scanned using CT settings designed for use with adult patients. Risk projections for leukaemia in relation to CT scanning to date have been based on extrapolations, primarily from atomic bomb data. As CT usage continues to grow and to become more widespread and technologies change, the understanding of any risks involved to patients is crucial. In this talk, an overview of ongoing studies of potentially increased risk of leukaemia following CT scans will be presented.