Estimation of absorbed fraction to the anterior nose from inhaled beta emitters

The main purpose of this research is to introduce a new and more realistic geometry for the anterior nose region (ET₁) as an alternative to the one provided in ICRP Publication 66. For a more accurate estimation of electron absorbed fraction (AF) to the nuclei of basal cells in the ET₁ region, the proposed new geometry (frustum of a cone) replaces the cylinder geometry, which was used in ICRP 66.

Since the electron absorbed fraction (AF) data in ICRP 66 are calculated based on the nose size for an adult Caucasian male, a second purpose of this research is to investigate how the nose size (different ethnic groups) and nose tissue composition (male, female and adolescent), affects the electron absorbed fraction values.

The third aim of this research is to develop a Monte Carlo program to estimate the electron energies that emerge from the surface of spherical dust particles. Given that electrons can be located anywhere between the center and the surface of the sphere, we vary the sphere radius from 0.5 to 50 μm and investigate the effects of self- absorption on the emitted electron energies and absorbed fraction.