BACKGROUND: Mesh nebulizers (MN) have lower residual volume and increased inhaled dose compared to jet nebulizers (JN) per in vitro and animal models. The aim of this study was to compare radioaerosol deposition using MN and JN in healthy subjects, using 2-D planar scintigraphy. METHODS: A randomized trial in 6 normal subjects (4 female, 2 male) inhaled 99mTc-DTPA with an activity of 1 mCi with the normal saline to a total dose of 4 mL with JN (Misty Max, Air Life, Yorba Linda, USA) oxygen flow of 8 L / min and 1.5 mL with MN (Aeroneb Solo with Ultra adapter; Aerogen Galway, Ireland). Scintigraphy was used to determine distribution of deposition and mass balance between compartments.

Inclusion Criteria:

• The study inclusion critera was healthy adults of both sexes, between 18 to 65 years, without history of lung disease or smoking, with forced vital capacity (FVC) or forced expiratory volume in the first second (FEV1) greater or equal to 80% of predicted values (Pereira et al., 1992), ability to follow and retain verbal commands while able and willing to provide signed consent to participate in this study.

Exclusion Criteria:

• Participants were excluded if they have been diagnosed with a lung disease, current smoker, unable to understand and follow the procedures and pregnant or unable to tolerate nebulization.