ABSTRACT
The possibility of predicting how particles will behave inside the respiratory tract has fascinated researchers for many years. The advantages of computational modeling are compelling, with its ability to extend measurement data beyond its original scope. In the past few decades, models have progressed from simple systems of one- or two-dimensional equations to highly sophisticated, three- and four-dimensional representations of form and function that account for the effects of disease, surgery, age, and ethnicity, and incorporate complex anatomy, particle characteristics, and transport mechanisms. Today’s respiratory deposition models combine several types of mathematical models to achieve this complexity, but a central feature is the use of three-dimensional (3D), anatomically accurate, computational fluid dynamics (CFD) that can provide detailed information about flow velocities and pressures through a specific geometry. Current imaging methods used to provide the anatomical domain for CFD cannot resolve important features of the deep lung, so other modeling methods, such as multiple-path lung dosimetry modeling and combined imaging and volume filling methods, are needed when the respiratory tract as a whole must be considered. The purpose of Chapter 3 is to provide a sense of the impact that CFD as well as other modeling approaches in whole lung/respiratory tract modeling have had on therapeutic aerosol research and development by describing the state of the art of human respiratory tract deposition modeling and discussing needs for future modeling efforts.
