Childhood cancer and low-dose ionizing radiation in Switzerland – the CALIRIS study

It is known that high doses of ionizing radiation can induce cancer and that children are particularly susceptible. However, the extent to which low doses, e.g. from natural radiation or imaging procedures in medicine (X-rays, CT scans) affect cancer risks in children unclear. At low doses, the expected effects are small and large studies are required to detect them.

As everyone else, children are constantly exposed to low doses of ionizing radiation from natural sources, so-called natural background radiation. For most people, doses received throughout their life from natural background radiation are the most important component of radiation exposure. Exposure to natural background radiation depends on where children live, time spent indoors and outdoors, and various building characteristics.

Our project aims to assess the association between natural background and childhood cancer and to estimate the contribution of common sources of low-dose ionizing, including natural background radiation and diagnostic radiology, to cancer risks in children. Specifically, we will:

  • Assess children’s exposure to common sources ionizing radiation in Switzerland through a survey and actual measurements using dosimeters. Read more
  • Develop statistical models to predict natural background radiation in Switzerland based on residential location information including location and building characteristics. Read more
  • Investigate associations between childhood cancer risks and predicted exposure to background radiation in a nationwide study in Switzerland.
  • Based on these results and the literature, predict the proportion of childhood cancer cases in Switzerland attributable to radiation exposure from different sources.

Our research should contribute to a better understanding of the cancer risk induced in children and adolescents by low-dose ionizing radiation. Ultimately, the project should improve the knowledge base for recommendations for medical diagnostic and radiation protection, to protect children from unnecessary exposure and thus from unnecessary cancer risk.


This project is funded by the Swiss National Science Foundation, grant number 320030_176218. Our research on exposure to ultraviolet radiation is funded by the Krebsliga, grant number KLS-4592-08-2018.

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