title: Supine lung clearance of Tc-99m DTPA and HMPAO aerosols.
abstract: The speed of Tc-99m DTPA/HMPAO radioaerosol clearance from the lungs that is represented as a slope from lungs to blood was measured in 23 male normal controls using commercial lung radioaerosol delivery units in the supine position in order to avoid the influences of gravity. The right lung was selected and three regions of interest were created for equal subdivisions of the upper, middle, and lower third. The results show that the clearance of Tc-99m DTPA/HMPAO aerosols in the upper lung is slowest. The differences between upper and lower lungs for Tc-99m DTPA/HMPAO aerosol clearances are significant. The clearance of Tc-99m DTPA aerosols was significantly faster than those of Tc-99m HMPAO in any region. The authors conclude that, although the effect of gravity disappears in the supine position in our study, the differences of aerosol clearance in different regions are still significant. Lipophilic Tc-99m HMPAO aerosols were slower than those of hydrophilic Tc-99m DTPA, which suggests there are at least two different mechanisms.
authors.affiliation: Department of Nuclear Medicine, Taichung Veterans General Hospital, Taiwan, Republic of China.
authors.forename: C H
authors.initials: CH
authors.lastname: Kao
authors.forename: H T
authors.initials: HT
authors.lastname: Lin
authors.forename: S L
authors.initials: SL
authors.lastname: Yu
authors.forename: S J
authors.initials: SJ
authors.lastname: Wang
authors.forename: S H
authors.initials: SH
authors.lastname: Yeh
mesh_terms: D000336:Aerosols; D000368:Aged; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D015609:Organotechnetium Compounds / Q000493:pharmacokinetics; D010091:Oximes / Q000493:pharmacokinetics; D011652:Pulmonary Circulation; D011877:Radionuclide Imaging; D016683:Supine Position; D019690:Technetium Tc 99m Exametazime; D016284:Technetium Tc 99m Pentetate / Q000493:pharmacokinetics
chemical_list: D000336:Aerosols; D015609:Organotechnetium Compounds; D010091:Oximes; D019690:Technetium Tc 99m Exametazime; D016284:Technetium Tc 99m Pentetate