Fractional Deposition of Radioactive Aerosols in the Respiratory Tract: Effects of Anatomical and Physiological Differences between Chinese and Caucasians

For the calculation of fractional deposition of radioactive aerosols, the deposition model in ICRP Publication 130 has been widely used. However, the deposition model is based on the anatomical and physiological characteristics of Caucasians. Since physiology and anatomical parameters of Chinese differ from those of Caucasians, this difference can affect the applicability of depositional models to Chinese people. ICRP suggests that the corresponding parameters can be replaced when the parameters of concerned people are known. Therefore, this paper investigates the physiological and anatomical parameters of Chinese people and establishes a respiratory deposition model applicable to Chinese people. It is found that the dependence of fractional deposition on aerosol particle size on Chinese people is qualitatively similar to that in Caucasian people. However, the value of fractional deposition is quantitatively different. When the AMAD (activity median aerodynamic diameter) is 1 μm (public exposure), the ratio of fractional deposition between Chinese and Caucasian light workers could reach up to 1.22 in the AI region, and the ratios of fractional deposition in other regions also ranged from 0.87-0.93; when the AMAD is 5 μm (occupational exposure), the ratio of fractional deposition between Chinese and Caucasian light workers could reach up to 1.35 in the AI region, and the ratios of fractional deposition in other regions also ranged from 0.95-1.30. The fractional deposition is used as input to biokinetic models to simulate the transport of radionuclides through the body after inhalation and ultimately impacts the dose conversion factor calculations.