How Reliable Is the Extrapolation? Localized Particle Deposition Patterns in Human/Rat Nasal Cavities

To improve the understanding of dose-response extrapolation from rat to human, regional micro-particle deposition patterns are numerically investigated and compared between human and rat realistic nasal cavities using Computational Fluid Dynamics (CFD). Resting breathing conditions are chosen and airflow patterns are visualised by streamlines. To have better comparisons of deposition patterns, deposited particles are projected into pre-divided 2D domains based on anatomical features using surface-mapping technique. The results show significant differences between human and rat due to the different nasal geometries, especially at vestibule regions. In human case, large micro-particles deposit primarily in vestibule, septum and pharynx and small micro-particles relatively scattered in the whole cavity. On the contrary, in the rat case, large and small micro-particles are captured by the first and second bend of vestibule region.