title: Charged particle equilibrium effects on the electron absorbed fraction in the extrathoracic airways.
abstract: Estimates of the dose to the extrathoracic airway (nasal vestibule) from inhaled beta-emitting radionuclides, obtained using the respiratory tract model presented in Publication 66 of the International Commission on Radiological Protection, frequently predict that the basal cells in this region are the most highly irradiated tissues of the body. The dose to the basal cells is averaged over a layer of tissue 10 microm thick located at a depth of 40 microm into the airway assuming that charged particle equilibrium exists. Since the target (basal cell layer) is very small and thin (10 cm(2) area and 10 microm thickness), charged particle equilibrium does not exist. In this work the effect on the absorbed fraction of the lack of charged particle equilibrium is investigated.
authors.affiliation: University of Tennessee, Department of Nuclear Engineering, Knoxville, TN 37996-2300, USA.
authors.forename: H M
authors.initials: HM
authors.lastname: Moussa
authors.forename: K F
authors.initials: KF
authors.lastname: Eckerman
authors.forename: L W
authors.initials: LW
authors.lastname: Townsend
mesh_terms: D001610:Beta Particles; D004583:Electrons; D006801:Humans; D008954:Models, Biological; D017785:Photons; D011829:Radiation Dosage; D011868:Radioisotopes; D012137:Respiratory System / Q000528:radiation effects*
chemical_list: D011868:Radioisotopes