title: Technetium-99m labeled micro aerosol "Pertechnegas". A new agent for ventilation imaging in suspected pulmonary emboli.
abstract: In this preliminary study, four patients suspected of having pulmonary emboli underwent ventilation imaging after inhaling approximately 1 mCi (37 MBq) of Tc-99m Pertechnegas (micro aerosol carbon particles labeled with Tc-99m) in five breaths or less. Planar images in multiple projections were recorded for preset counts. A final posterior image was acquired to evaluate residual lung background activity. Immediately following ventilation imaging, perfusion imaging in the identical projections was performed using 4 mCi (148 MBq) of Tc-99m MAA. Two of the four patients demonstrated matched uniform ventilation and perfusion and two showed segmental ventilation-perfusion "mismatched" defects consistent with pulmonary emboli. In each case, residual Pertechnegas background lung activity (count rate) at the end of the last ventilation image was less than 10% of the initial Tc-99m MAA counts (count rate). The advantages of Pertechnegas, in comparison to aerosolized DTPA, include: less residual ventilation image activity superimposed on the MAA perfusion images, reduced demand for patient cooperation due to fewer required breaths (five or less), and lack of deposition of activity in the central airways. The authors conclude that Pertechnegas has properties that make it ideally suited for routine lung ventilation imaging.
authors.affiliation: Department of Radiology, University of California San Diego Medical Center 92103-8758.
authors.forename: W L
authors.initials: WL
authors.lastname: Ashburn
authors.forename: E V
authors.initials: EV
authors.lastname: Belezzuoli
authors.forename: W A
authors.initials: WA
authors.lastname: Dillon
authors.forename: B D
authors.initials: BD
authors.lastname: Mensh
authors.forename: D
authors.initials: D
authors.lastname: Hoogland
authors.forename: D W
authors.initials: DW
authors.lastname: Yeung
authors.forename: G E
authors.initials: GE
authors.lastname: Coade
mesh_terms: D000328:Adult; D005260:Female; D006108:Graphite; D006801:Humans; D008297:Male; D008875:Middle Aged; D011655:Pulmonary Embolism / Q000000981:diagnostic imaging*; D011877:Radionuclide Imaging; D013670:Sodium Pertechnetate Tc 99m
chemical_list: C056708:Technegas; D006108:Graphite; D013670:Sodium Pertechnetate Tc 99m