Aerosol Deposition: Practical Considerations of Methodology for the Direct Measurement of Aerosol Delivery to the Lung Bronchiolar-Alveolar Surfaces

ABSTRACT

There is an increasing scientific and medical awareness that the efficiency of aerosol delivery to the peripheral lung parenchyma is variable. Recently, the concept of direct calculation of the amount of a radiolabeled nebulizer solution deposited in the lung has been described. This method uses calibrating intravenous doses of radiolabeled macroaggregated albumin to convert scintigraphically obtained lung region-of-interest counts to units of radioactivity. By measuring the amount of activity loaded into the nebulizer, this conversion permits calculation of the percentage of the initial nebulizer dose that was actually deposited in the lung. Some practical considerations and limitations of applying this nuclear medicine methodology to investigate the deliverability of radiolabeled substances in a nebulizer to the gas exchange regions of the lung are discussed.