Abstract
Some epidemiology studies have reported that the relationship between radon and lung cancer was positive. Recently it was revealed that high thoron concentration exist at one of the reported area by our examination. Thoron is the isotope of radon, and its half-life is shorter than radon. On the other hands, the half-life of thoron decay products is longer than those for radon. Alpha energy of thoron decay products is also higher than radon. Dose conversion factor of thoron is also higher than radon. Thus thoron may affect the relationship between radon and lung cancer. To consider for effects of thoron, the biological experiment should be done with same experiment system of radon. The biological experiment for thoron is rare, so we tried to expose thoron with in vitro condition. The air-liquid interface culture that was constructed for radon experiments was used to culture system for thoron exposure. The preliminary data for thoron experiments will be reported.
