Controlled, parametric, individualized, 2D and 3D imaging measurements of aerosol deposition in the respiratory tract of healthy human volunteers: in vivo data analysis

To provide a validation dataset for aerosol deposition modeling, a clinical trial was performed in which the inhalation parameters and the inhaled aerosol were controlled or characterized. Eleven, healthy, never-smokers, male participants completed the study. Each participant performed two inhalations of (99m)Tc-labeled aerosol from a vibrating mesh nebulizer, which differed by a single controlled parameter (aerosol particle size: "small" or "large"; inhalation: "deep" or "shallow"; carrier gas: air or a helium-oxygen mix). The deposition measurements were made by planar imaging, and single photon emission computed tomography-computed tomography (SPECT-CT). The difference between the mean activity measured by two-dimensional imaging and that delivered from the nebulizer was 2.7%, which was not statistically significant. The total activity deposited was significantly lower in the left lung than in the right lung (p