ACPSEM Statement – Radiation Exposure Risks from CT scans in Childhood

Computed tomography (CT) imaging is an important clinical tool that uses ionising radiation in the form of x-rays to allow for the quick visualisation and diagnosis of a multitude of medical conditions.  In general, concerns exist that the associated ionising radiation may have detrimental effects, particularly for children.

Several studies have been and are being conducted worldwide to assess the potential risks of paediatric CT imaging.   A recently published epidemiological study from Great Britain has linked CT imaging of children and young adults to a small increase in the risk of developing cancer later in life.  This reported result is broadly consistent with current scientific thinking that ionising radiation is a known carcinogen.

The absolute risks reported in this recent study are very low. The study reports that the relative risks might almost triple the risk of leukaemia and brain tumours due to multiple CT scans. These cancers are relatively rare and since the background risk is very low, a doubling or tripling of the risk is still a very low risk.

The immediate benefits of CT imaging significantly outweigh any long-term risks.  In general, CT imaging is used to diagnose serious health conditions and the health risk of not having a CT scan is likely to be significantly higher than the risk from the radiation exposure.

The ACPSEM advocates that CT scanning should only be performed when it is clinically justified and performed with the lowest possible radiation dose to obtain the diagnostic information required.  Alternative procedures that do not involve ionising radiation, such as magnetic resonance imaging (MRI) and ultrasound should be considered.  All CT scanners should undergo a process of image and dose optimisation in collaboration with a certified medical physicist to ensure that the best diagnostic image quality is being delivered at the lowest possible radiation dose to the patient.

Reference: Pearce, MS et al, Radiation exposure from CT scans in childhood and subsequent risk of leukaemia and brain tumours: a retrospective cohort study, The Lancet, published online 7 June 2012, doi:10.1016/S0140-6736(12)60815-0