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.