Doses from beta radiation in sensitive layers of human lung and dose conversion factors due to ²²²Rn/ ²²⁰Rn progeny

Abstract

Great deal of work has been devoted to determine doses from alpha particles emitted by 222Rn and 220Rn progeny. In contrast, contribution of beta particles to total dose has been neglected by most of the authors. The present work describes a study of the detriment of 222Rn and 220Rn progeny to the human lung due to beta particles. The dose conversion factor (DCF) was introduced to relate effective dose and exposure to radon progeny; it is defined as effective dose per unit exposure to inhaled radon or thoron progeny. Doses and DCFs were determined for beta radiation in sensitive layers of bronchi (BB) and bronchioles (bb), taking into account inhaled 222Rn and 220Rn progeny deposited in mucus and cilia layer. The nuclei columnar secretory and short basal cells were considered to be sensitive target layers. For dose calculation, electron-absorbed fractions (AFs) in the sensitive layers of the BB and bb regions were used. Activities in the fast and slow mucus of the BB and bb regions were obtained using the LUNGDOSE software developed earlier. Calculated DCFs due to beta radiation were 0.21 mSv/WLM for 222Rn and 0.06 mSv/WLM for 220Rn progeny. In addition, the influence of Jacobi room parameters on DCFs was investigated, and it was shown that DCFs vary with these parameters by up to 50%. © 2011 Springer-Verlag.