Radiation Protection Dosimetry Advance Access originally published online on January 11, 2007
Radiation Protection Dosimetry 2006 122(1-4):345-348; doi:10.1093/rpd/ncl492
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Modeling lung cancer incidence in rats following exposure to radon progeny
1 Division of Physics and Biophysics, Department of Molecular Biology, University of Salzburg, Salzburg, Austria
2 Department of Environmental Sciences and Engineering, Carolina Environmental Program, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
3 IRSN, Fontenay-aux-Roses, France
* Corresponding author: Werner.Hofmann{at}sbg.ac.at
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Abstract |
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Lung cancer incidence in Sprague–Dawley rats was simulated by a biologically based carcinogenesis model, which is formulated mathematically in terms of a stochastic state-vector model. Doses to the sensitive target cells in the bronchial epithelium of the rat lung were calculated by a stochastic dosimetry model, considering the distinct monopodial branching structure and the crossfire of alpha particles from alveolar tissue to bronchial epithelium. Bronchial and alveolar cellular doses could reasonably be approximated by lognormal distributions, with geometric standard deviations (GSD) between 7 and 10, depending on exposure conditions. Based on a dose-exposure conversion factor of 8.5 mGy WLM–1 and a GSD of 8, lung cancer incidences were calculated for each cumulative exposure category in the rat inhalation study, consisting of different exposure rates and exposure times. The fair agreement between theoretical predictions and experimental data over the whole exposure range emphasises the necessity to incorporate the full cellular dose distributions rather than their mean values.