『Abstract
　The relationship of soil gas radon Rn²²² and indoor radon was studied within the Quaternary fluvial sediments of the Czech Republic. The processing of data selection from the radon database of the Czech Geological Survey and indoor radon data (database of the National Radiation Protection institute) has proved the concentration dependence of radon in Quaternary fluvial sediments on deeper bedrock. The ArcGIS processing was accompanied by the field verification in five profiles, intersecting the granitoid Central Bohemian Plutonic Complex and its rim rock types. Both theoretical and experimental results show dependence of soil gas radon and indoor radon concentrations in Quaternary fluvial sediments on deeper geological basement, thus leading to the conclusion that the lateral transport of Quaternary sediments does not play such a dominant role in radon concentrations, as was thought previously. This fact will enable to determine precisely the radon index of Quaternary sediments (in the Czech radon mapping classified as an intermediate index) into three categories according to the lithology of their geological basement.

Keywords: Soil gas radon; Indoor radon; Radon index; Quaternary sediments; Bohemian Massif』

Introduction
Method
Results
　Cross section 1: Skalice (NW-SE), 14 test sites
　Cross section 2: Mastnik (NW-SE), 23 test sites
　Cross section 3: Chotysanka (SW-NE), 16 test sites
　Cross section 4: Kocaba (SW-NE), 6 test sites
Discussion
Conclusions
Acknowledgments
References