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Application of ICRP Biokinetic Models to Depleted Uranium
Published in Alexandra C. Miller, Depleted Uranium, 2006
For a radioactive aerosol, the amount of activity per unit size, rather than the number of particles, is usually considered. For particles of about 1 μm or larger, when sedimentation and impaction are important, and aerodynamic diameter, dae, is the appropriate measure of behavior, the aerosol would be characterized by the activity median aerodynamic diameter, AMAD: 50% of the activity is associated with particles larger than the AMAD. For smaller particles, for which diffusion dominates, and thermodynamic diameter, dth, is the appropriate measure of behavior, the aerosol would be characterized by the activity median thermodynamic diameter, AMTD: 50% of the activity is associated with particles larger than the AMTD.
Biokinetic Models
Published in Shaheen A. Dewji, Nolan E. Hertel, Advanced Radiation Protection Dosimetry, 2019
Biological half-times for the TGLM are given in Table 6.1 . Deposition fractions depend on the particle size. For the default particle size of 1 μm AMAD (activity median aerodynamic diameter) assigned in ICRP Publication 30, the deposition fractional assigned to the total respiratory tract is 0.63, of which 0.30 is assigned to NP, 0.08 to TB, and 0.25 to P.
Radiation exposures from the beneficial use of alumina production residue
Published in Journal of the Air & Waste Management Association, 2019
Stephen Marschke, William Rish, John Mauro
In addition to the airborne dust loading, the inhalation dose to a worker depends strongly on the particle size distribution and solubility. ICRP (2002) provides a detailed description of the human respiratory tract model, which establishes the basis for the inhalation dose conversion factors (DCFs) that are used by all regulatory authorities throughout the U.S. and abroad. The inhalation DCFs presented below, which are published by the EPA in Federal Guidance Report No. 13, are based on the ICRP recommendations. The biokinetic behavior and clearance rate of any inhaled aerosol depend on a parameter referred to as the activity median aerodynamic diameter (AMAD). The size, shape, and density of aerosols are highly variable and affect the deposition pattern and clearance rate of the aerosol in the lung. For this reason, particle sizes are expressed in terms of a standardized metric, the AMAD, which is defined as the diameter of a unit density sphere with the same terminal settling velocity in air as that of an aerosol particle whose activity is the median for the entire aerosol (Shleien, Slaback, and Birky 1998); in other words, a sphere with a diameter of 1 micron and density of 1 gram per cubic centimeter. A vast amount of research has resulted in ICRP recommending that the default particle size for deriving inhalation doses from aerosols is a 5-micron AMAD, which is the value used in the inhalation dose calculations described herein.