Rationale: Cystic fibrosis (CF), is a disease characterized by airway liquid surface dysregulation, decreased depth of
periciliary fluid and abnormal hydration of mucus, which impede mucociliary clearance and contribute to repeated bacterial
infections. CF­specific biomarkers are needed to provide rapid outcome measures of treatment efficacy. One such a
biomarker is liquid epithelial absorption (LA), which has been shown to be elevated in CF subjects compared with that of nonCF
controls. LA is currently measured dual radionuclide scintigraphy, which is spatially and quantitatively limited, and unable
to assess changes in smaller airways most affected in the early stages of disease progression. To circumvent those
limitations, we applied a new imaging technique (multiplexed PET, mPET) for simultaneous dynamic imaging of two PET
tracers in vivo. Aims: 1) demonstrate the feasibility of measuring quantitatively LA and muco­ciliary transport (MCT) in the
airways of normal pigs using mPET. 2) evaluate the effect of hypertonic saline solution inhalation, a common therapy for CF, in
LA.