Simulation of radiation damage to lung cells after exposure to radon decay products.

OBJECTIVES: Exposure to radon and radon decay products represents one of the greatest risks of ionizing radiation from natural sources in some residential and working areas. Recently increasing attention has been paid to accurate estimations of this health risk by using various models.

METHODS: In the presented study, a bystander model was used to predict biological effects of radon products on lung tissue target cells. The model considers radiation response as a superposition of the direct alpha particles hit effect and the bystander (cells communication) effect. Energy deposition in the lung tissue and in the air gap was calculated using the Bethe-Bloch equation. The exponential distribution of radon progenies in the mucous layer of smokers and non-smokers was evaluated.

RESULTS: The excess relative risk value of lung cancer occurrence per unit exposure obtained in our study was ERR/WLM=0.0047 for smokers and ERR/WLM=0.0171 (taking into account the environment in radioactive ore mines) for non-smokers. Other published results give the average excess relative risk values per unit exposure in the dwellings for smokers ERR=0.050 per 100 Bq.m(-3) and for non-smokers ERR=0.198 per 100 B.qm(-3). Results presented in this study are in good agreement with the published epidemiological data on lung cancer incidence for mines and residential areas.

CONCLUSIONS: The bystander model is suitable for radon risk prediction in dwellings and at workplaces (residential and working areas).