Epidemiological study to quantify risks for paediatric computerized tomography and to optimise doses

The EPI-CT Project is a major international collaboration. The purpose of the project is to establish a European cohort of children under 20 years who have undergone at least one CT examination, initially to estimate the risk of leukemia and brain tumours. After an extended follow-up period, it is also planned to analyze different malignancies and possibly other adverse health effects. The work is coordinated by the International Agency for Research on Cancer (IARC). Contributions from 11 European countries (Belgium, Denmark, Germany, Finland, France, Luxembourg, Netherlands, Spain, Sweden, United Kingdom and Norway) is the foundation of this European cohort, which consists of a total of 1 million children and adolescents. Norway, through the joint efforts of the Cancer Registry of Norway an the Norwegian Radiation Protection Authority, has contributed with information regarding 85 000 children and adolescents who have undergone at least one CT examination in the period 1980 to 2012. This is considerably more than 20,000 individuals that we estimated to include originally. The EPI-CT project will give a new dataset where the size of the cohort and the accuracy of dose estimates far surpasses previous studies. EPI-CT will come to improve our knowledge about the relationship between CT examinations and cancer risk. This is important for the justified and optimized use of CTs in the clinics. A cohort profile paper was published in 2018, and will be followed by papers on risk estimates and dose distributions.

Vi forventer økt kunnskap om effekter av eksponering for CT-undersøkelser av barn, og at dette vil medføre mer hensiktsmessig og målrettet bruk av denne viktige og nyttige undersøkelsesmetoden.

Diagnostic radiation represents an indispensable, sometimes life-saving, tool in modern medicine. However, the growing use of computerized tomography (CT) exams is a topic of concern in radiological protection, especially for children and adolescents. Chi ldren are generally more sensitive to the carcinogenic effects of ionizing radiation than adults. In addition, they have a longer life-span to express any effect and, because of their smaller mass, they may receive higher radiation doses from a CT exam th an an adult. Scientists from nine European countries with expertise in epidemiology, clinical practice, radiology, dosimetry, biology and public health will contribute to the project with the objective of provide recommendations for a common approach to C T dose optimisation for paediatric patients in Europe. A large-scale multinational cohort comprising more than 1 million children aged 0-20 years who have received one or more CT scans will be established. The sub-cohort from Norway is estimated to compri se approximately 20,000 subjects who have undergone CT scans from 2005 until present. Detailed radiological data will be collected, as well as information on possibly important covariates (such as socio economic status of family or Down syndrome). After d ose reconstruction, linkage with the Cancer Registry database will be done. Analyses using external and internal comparisons (Cox regression) will be performed to estimate the leukaemia risk associated with number and type of scans as well as with radiati on dose. Analyses will also be done to estimate risk of all cancer types combined and cancer mortality. Results of this research will serve to increase awareness in the scientific and medical communities about public health aspects related to the use of d iagnostic radiation and form the basis of recommendations on the use of valuable diagnostic tools, with lowering the risk of its potential hazards as much as possible.