title: Radioaerosol assessment of mucociliary clearance: towards definition of a normal range.
abstract: Radioaerosol measurements of mucociliary clearance have been assessed in relationship to depth of particle penetration into the lung. The tests analysed were performed with 5 microns diameter 99Tcm particles inhaled under standardised conditions but at varying inhalation flow rates. Aerosol lung penetration was assessed by (i) penetration index (PI), a ratio of outer to inner zone radioactivity determined from a gamma camera image; and (ii) alveolar deposition (AD), a measure of activity retained at 24 hours and taken to represent deposition distal to the ciliated airways. Clearance rates in 30 tests on 19 normal non-smokers under the age of 50 varied significantly with aerosol inhalation flow rate, PI and AD. A normal range varying with PI is proposed although normal inter-subject variability remains high even after allowance for PI. Nevertheless 8 out of 12 patients with stable asthma and 21 out of 24 patients with chronic bronchitis demonstrated slow clearance lying outside the PI-based normal range.
mesh_terms: D000328:Adult; D000336:Aerosols; D000368:Aged; D001249:Asthma / Q000503:physiopathology; D001692:Biological Transport; D001980:Bronchi / Q000502:physiology; D001991:Bronchitis / Q000503:physiopathology; D002908:Chronic Disease; D002923:Cilia / Q000502:physiology; D005260:Female; D006801:Humans; D008168:Lung / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D009093:Mucus / Q000502:physiology*; D012016:Reference Values; D013667:Technetium; D014132:Trachea / Q000502:physiology
chemical_list: D000336:Aerosols; D013667:Technetium