The Range of the Bystander Effect Signal in Three-Dimensional Tissue and Estimation of the Range in Human Lung Tissue at Low Radon Levels

It is shown in the measurements of Belyakov et al. (Proc. Natl. Acad. Sci. USA 102, 14203-14208, 2005) that the distribution of microbeam-irradiated cells represents a finite line source distribution for the emission of bystander effect signals. By assuming a plane source configuration for the propagation of the bystander effect deleterious signal, in the modeling analysis of Shuryak et al. (Radiat. Res. 168, 741-749, 2007) there is an overestimate of the range to effectiveness. A correction is provided to this analysis to estimate the bystander signal propagation distance in the case of low domestic radon levels where single isolated cells are "hit" by a particles and emit the bystander signals as a "point" source to neighboring bystander effect receptor cells. The result is an estimate, but it shows that with the spatial correction the deleterious propagation range would be of the order of 210 mu m, a factor of about 5 less than prior predictions. (C) 2009 by Radiation Research Society