New study on CT scans and cancer risk in children published

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Computed tomography (CT) examinations can provide important information. However, they are also associated with a higher radiation dose than conventional X-rays. A recent study by the International Agency for Research on Cancer (IARC) and other stakeholders now provides an estimate of the additional risk of brain tumours in children and young adults who have undergone a CT scan of the head based on extensive individual patient data.

The study, which was published on 7 December in the journal "The Lancet Oncology", shows a significant dose-response relationship between the CT-related radiation dose to the brain and the risk of brain tumours. It thus confirms indications from earlier studies that radiation exposure from computer tomography (CT) examinations increases the risk of brain tumours in children.

The absolute risk for an individual person of developing a brain tumour resulting from radiation exposure from a CT scan is quite low overall. However, in view of the around 55,000 CT scans of the head in children and adolescents in Germany every year, the study emphasises the particular importance of observing the principles of radiation protection in medicine.

The work is part of the European EPI-CT cohort study, which is coordinated by the IARC. Researchers from IARC and partner institutions analysed data from 658,752 children who had received one or more CT scans. They concluded that one in 10,000 children who receive a CT scan of the head can be expected to develop a radiation-associated brain tumour within 5–15 years of the CT scan.

Special importance for radiation protection

The results of this study are particularly important for radiation protection. It is the largest international study to date on CT-related cancer risks in young patients with individualised dose assessment. The EPI-CT cohort comprises around one million children from 276 hospitals in nine European countries.

In the view of the Federal Office for Radiation Protection, the results form an important basis for further developing the high level of radiation protection in medicine. If CT is unavoidable, the examination must be optimised in terms of dose (i.e. performed with the lowest possible radiation dose). In Germany, there are diagnostic reference values for CT examinations in children of different ages; these may not be exceeded on average across a patient group.

Irrespective of this, CT examinations should be carried out only if there is a clear indication for this. This principle of "justifiable indication" is applied particularly strictly to children and adolescents in Germany.