Validation of a spatial model of background radiation using personal measurements in children.

Background Limited knowledge about the prediction accuracy of exposure models hinders the interpretation of results from epidemiological studies on childhood cancer risks associated with exposure to background gamma-radiation.Objective We aimed to validate a spatial exposure model that we recently developed for Switzerland.Methods We used individual exposure measurements conducted with D-Shuttle dosimeters by 149 children throughout the country. We ran linear regression models fitting the measured exposure against predictions from the newly developed model, and compared results with the predictions from an earlier model. We further used variograms to investigate the spatial correlation of estimation errors.Results The prediction accuracy of the newly developed exposure model was modest (R2 = 0.2), but better than the earlier model (R2 = 0.13). Prediction errors revealed weak spatial correlation.Discussion Although the new exposure model marks an improvement, the modest prediction accuracy and the remaining spatial correlation of errors show room for further improvement. Our study highlights the need for validation of exposure models for background gamma-radiation used in epidemiological studies.