The recent development of radiolabelled, monodisperse, sebacate aerosols has allowed the simultaneous quantitative measurement of aerosol lung deposition using Tyndallometry (continuous concentration measurement at the mouth), gamma camera imaging, and filter collection of exhaled aerosol. This study demonstrates a close correlation between Tyndallometry and the other two techniques (r = 0.965, p < 0.001 and r = 0.934, p < 0.001, respectively). Systematic differences were observed between the gamma camera and Tyndallometric measurement which could be explained by regional inhomogeneities in gamma camera calibration. Similar differences were observed when comparing Tyndallometry to collected exhaled aerosol which could be explained by aerosol losses in the experimental apparatus. The accuracy and reproducibility of the Tyndallometric technique suggests that it is the best method for measurement of total aerosol deposition and can be combined with nuclear imaging for quantitative regional studies.

Monodisperse aerosols containing a range of chemical material, including pharmacologically active substances, were produced by using a modified Sinclair-LaMer condensation generator. Instead of the usual hot-wire technique, an ultrasonic nebulizer was used to suspend nuclei in the gas phase as an aqueous polydisperse aerosol. This technique allowed the generation of monodisperse oil (sebacate) aerosols containing nuclei of sodium chloride, histamine, methacholine, antigen, iron oxide, methylene blue, uranine, radioactive technetium pertechnetate, and technetium-labeled human serum albumin. Quantitative agonist activity was demonstrated for each active nucleus. Particle sizes ranged from 0.65 to 3 microns, with a geometric standard deviation of 1.1-1.2. This system can produce a stable, monodisperse, biologically active radiolabeled aerosol for a period of several hours.