Technegas for inhalation lung imaging

Isawa, Toyoharu; Teshima, Takeo; Anazawa, Yoshiki; Miki, Makoto; Motomiya, Masakichi

doi:10.1097/00006231-199101000-00006

Cited by 38 publications

(22 citation statements)

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“…This is in contrast to the earlier report by Busch et al [4] and supports the observations of Isawa et al [2] and Strong and Agnew [6]. As our PCS measurements show, TcG particles actually have an average size of 60-160 nm.…”

Section: Discussionsupporting

confidence: 90%

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Technegas: a study of particle structure, size and distribution

Lemb¹,

Oei²,

Eifert

et al. 1993

Eur J Nucl Med

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Technegas (TcG) was produced using a commercially available TcG generator. The structure and size distribution of TcG particles were examined by means of the following methods: (a) transmission electron microscopy (TEM), range: 1 nm-100 microns; (b) time-of-flight mass spectroscopy (MS), range: < 3 nm; (c) photon correlation spectroscopy (PCS), range: 3 nm-3 microns. The TEM images showed graphite particles (size 7-23 nm) agglomerated into larger secondary aggregates. The size of these aggregates, determined from PCS and TEM measurements, showed a log-normal distribution and typically ranged from 60 to 160 nm. No isolated particles smaller than 3 nm could be detected by MS. We conclude that TcG particles consist of technetium-99m labelled agglomerated graphite particles and have an average size of 97 nm (geometrice standard deviation (GSD): 1.55).

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Section: Discussionsupporting

confidence: 90%

“…According to various studies, TcG applied to normal subjects has the following characteristics: alveolar deposition, almost no central deposition and no mucociliary clearance [1,2]. The distribution of TcG in the lungs is governed by regional ventilation [3].…”

Section: Introductionmentioning

confidence: 99%

Technegas: a study of particle structure, size and distribution

Lemb¹,

Oei²,

Eifert

et al. 1993

Eur J Nucl Med

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“…The appearance of the technegas particles is similar to that described by Isawa et al (1991). We did not identify small isolated spheres in the technegas aerosol, as observed by Lemb et al, (19931, but the aggre- gates that they describe are similar to what we found.…”

Section: Resultssupporting

confidence: 90%

“…TEM has been employed to examine technegas particles (Isawa et al, 1991;Lemb et al, 1993). A description of pertechnegas particles has not yet been reported.…”

Section: Introductionmentioning

confidence: 99%

Transmission Electron Microscopic Observations on Technegas and Pertechnegas

Scalzetti

Gagne

Scott

et al. 1998

Aerosol Science and Technology

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ABSTRACT. We examined the features of technegas, pertechnegas, and related nonradioactive aerosols using transmission electron microscopy. Samples of technegas, pertechnegas and unlabeled saline aerosols were created and collected within the Technegas Generator. The samples were examined by transmission electron microscopy and electron energy-loss spectroscopy (EELS). Technegas, pertechnegas, and the unlabeled saline aerosol particles have the same ultrastructure. Heating by the electron beam produces damage in some of these particles, revealing an opaque core material that is water soluble, and a thin surface layer. Disappearance of chlorine is noted by EELS during heating. We conclude that all of the examined aerosols have the same ultrastructure, regardless of the presence of small concentrations of oxygen during particle formation, and regardless of the presence of the technetium-99m label. We also note that some particles are susceptible to damage by heating; these consist of a thin surface layer and an opaque core substance that is dissipated upon heating.

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“…Its penetration characteristics are gas-like, as it has a smaller and more uniform particle size than other aerosols (Burch etal. 1986;Hilson et al 1989;Isawa et al 1991 ;Strong and Agnew 1989). The regional distribution of Technegas has been found to be no different to that of xenon-133 in both normal lungs ) and in lungs with severe airflow limitation ).…”

Section: Introductionmentioning

confidence: 99%

An evaluation of Technegas as a ventilation agent compared with krypton-81 m in the scintigraphic diagnosis of pulmonary embolism

Cook

Clarke

1992

Eur J Nucl Med

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A ventilation agent that provides good quality lung images, which is cheap, easy to use and non-toxic, with a low radiation dose, has long been sought. Technegas, an ultrafine aerosol of technetium-99m-labelled carbon, was developed with these qualities in mind. We have studied Technegas in a clinical setting to evaluate some of these qualities. Twenty-five patients referred with a diagnosis of suspected pulmonary embolism were investigated during the same study using both krypton-81 m and Technegas as ventilation agents in conjunction with 99mTc-macroaggregated albumin as a perfusion agent. Technegas provided images which were of satisfactory quality. Images were obtained relatively easily and without discomfort to the patient, and Technegas has the advantage of always being available. A semi-quantitative regional assessment was employed which showed a good correlation (r = 0.499, P less than 0.001) between Technegas and krypton-81 m ventilation. We report on an effect not previously found to be significant, that is lung regions were better ventilated with Technegas than with krypton-81 m. This altered the diagnostic probability rating of pulmonary embolism in a number of patients (n = 3, 12%) compared with krypton-81 m. This effect was also noted in a further 8 patients (32%) without a change in the diagnostic probability. We offer possible explanations for this phenomenon.

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Technegas for inhalation lung imaging

Cited by 38 publications

References 0 publications

Technegas: a study of particle structure, size and distribution

Technegas: a study of particle structure, size and distribution

Transmission Electron Microscopic Observations on Technegas and Pertechnegas

An evaluation of Technegas as a ventilation agent compared with krypton-81 m in the scintigraphic diagnosis of pulmonary embolism

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