Alpha-particle lineal energy spectra for the human lung

Abstract

Purpose : To determine the distribution of lineal energy in the target cells and the parameters of distribution for various combinations of sources, targets and energies in the human tracheobronchial tree. Frequency average and average of the square of the lineal energy were also calculated from the lineal energy distribution. Method : A model was created to simulate the geometric distribution of cell nuclei in the airway of the tracheobronchial tree. Propagation of alpha particles in such a model was simulated by the Monte Carlo method. Microdosimetric distributions of lineal energy were calculated. Results : Distributions of lineal energy were substantially different for basal and secretory cells. The frequency average of specific energy was found to be between 0.3 Gy and 0.4Gy. Conclusions : Interactions of alpha particles with basal and secretory cells show significant differences: events with small energy transfer are dominant for basal cells, while those with large transfer are dominant for secretory cells. This finding can influence dose weightings and yield lower values of the dose-to-exposure coefficient.