title: The effect of forced expiration on the uniformity of 99Tcm-DTPA aerosol ventilation images in patients with excess sputum production.
abstract: This study examines the use of the forced expiratory technique (FET) as a means of improving the uniformity of radionuclide aerosol ventilation images in patients with excess sputum production. Ventilation images are objectively classified by two computer derived indices to characterize the degree of radioaerosol clumping and overall uniformity. In a series of twenty five patients with a long-standing history of daily sputum production, images acquired before and after forced expiration and again after a second ventilation immediately following FET showed no significant change in either index. The results obtained do not provide evidence to support the routine use of FET in conjunction with radioaerosol scintigraphy. The method of image classification correlates well with a visual assessment of image uniformity and has general application.
authors.affiliation: Department of Medical Physics, Royal Hallamshire Hospital, Sheffield, UK.
authors.forename: E
authors.initials: E
authors.lastname: Middleton
authors.forename: C
authors.initials: C
authors.lastname: Clout
authors.forename: C
authors.initials: C
authors.lastname: Occleshaw
authors.forename: W B
authors.initials: WB
authors.lastname: Tindale
authors.forename: B V
authors.initials: BV
authors.lastname: Parker
authors.forename: D C
authors.initials: DC
authors.lastname: Barber
authors.forename: N A
authors.initials: NA
authors.lastname: Barrington
mesh_terms: D000336:Aerosols; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging*; D011877:Radionuclide Imaging; D012129:Respiratory Function Tests; D013183:Sputum / Q000378:metabolism*; D016284:Technetium Tc 99m Pentetate / Q000008:administration & dosage
chemical_list: D000336:Aerosols; D016284:Technetium Tc 99m Pentetate