title: 99Tcm-Technegas and krypton-81m ventilation scintigraphy: a comparison in known respiratory disease.
abstract: Krypton-81m gas, by virtue of its imaging characteristics, is often considered the "gold standard" for ventilation scintigraphy but its use is restricted by its high cost and limited availability. The new radiopharmaceutical 99Tcm-Technegas, a suspension of ultrafine technetium-99m labelled carbon particles, produces high-quality images of ventilation and has the advantage of continuous availability. As part of our evaluation of Technegas the two were compared in 40 patients with a variety of established respiratory diseases. Disparities were seen in five patients in five diagnostic groups and may be a consequence of the differing physical properties of the two agents and the different inhalation techniques used. In addition two interesting features were noted on the Technegas images. (1) Hot spots were seen in 50% of patients, particularly in those with a degree of airways obstruction; (2) preferential basal deposition of activity was seen in 30%, particularly in patients with idiopathic pulmonary fibrosis. Both features were significantly associated with parameters of pulmonary function indicating obstructive lung disease in the former case and restrictive lung disease in the latter.
authors.affiliation: Department of Nuclear Medicine and Medical Physics, Manchester Royal Infirmary, UK.
authors.forename: J M
authors.initials: JM
authors.lastname: James
authors.forename: J J
authors.initials: JJ
authors.lastname: Lloyd
authors.forename: B C
authors.initials: BC
authors.lastname: Leahy
authors.forename: S
authors.initials: S
authors.lastname: Church
authors.forename: C C
authors.initials: CC
authors.lastname: Hardy
authors.forename: R A
authors.initials: RA
authors.lastname: Shields
authors.forename: M C
authors.initials: MC
authors.lastname: Prescott
authors.forename: H J
authors.initials: HJ
authors.lastname: Testa
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D005541:Forced Expiratory Volume; D005652:Functional Residual Capacity; D006801:Humans; D007727:Krypton Radioisotopes; D008168:Lung / Q000000981:diagnostic imaging* / Q000503:physiopathology; D008171:Lung Diseases / Q000000981:diagnostic imaging* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D011877:Radionuclide Imaging; D012119:Respiration; D013670:Sodium Pertechnetate Tc 99m; D014109:Total Lung Capacity; D014797:Vital Capacity
chemical_list: D007727:Krypton Radioisotopes; C056708:Technegas; D013670:Sodium Pertechnetate Tc 99m