Comparison of99mTc-Technegas SPECT with133Xe dynamic SPECT in pulmonary emphysema

Abstract

This study was undertaken to compare axial images of 99mTc-Technegas SPECT (Technegas) with those of 133Xe gas dynamic SPECT in patients with pulmonary emphysema. There were 20 patients, 19 males and 1 female. All patients except one ex-smoker were heavy smokers with a mean age of 68.1 years. For Technegas scintigraphy, the patients inhaled 505 MBq 99mTc-Technegas in several tidal volume breaths in the supine position without breath holding. For 133Xe gas scintigraphy, the patients inhaled 370 MBq 133Xe gas. 133Xe gas dynamic SPECT was performed in the equilibrium phase for the last minute of the 3 minute inhalation in a closed circuit, and in the washout phase for 6 minutes of inhalation in a semi-closed circuit, by means of a gamma camera with dual detectors (Picker model Prism 2000). Abnormal findings included heterogeneity, defects and hot spots on Technegas images and on retention images taken 3 minutes after 133Xe gas washout. In 2 of 20 patients, the degree of abnormal findings on Technegas images depended on the area of 133Xe gas retention in the washout phase. In 3 patients, the degree of abnormal findings on both Technegas SPECT and 133Xe gas dynamic SPECT images were equivalent. In the remaining 15 patients, more detailed findings and a greater area were shown by Technegas SPECT than 133Xe gas dynamic SPECT. We conclude that in patients with pulmonary emphysema Technegas SPECT can demonstrate ventilation impairment more easily than 133Xe gas dynamic SPECT.

Quantitative analysis of pulmonary emphysema: three-dimensional fractal analysis of single-photon emission computed tomography images obtained with a carbon particle radioaerosol.

“…pulmonary emphysemaâ€"evenmild abnor malitiesâ€"than does CT and reveal ventila tion impairment more easily than does xenon-133 dynamic SPECT [13,15]. On the other hand, pathologic changessuch as emphysemaand bulla formation result mainly in obstructive pulmonary impairment.…”

Tc-99m Technegas scintigraphy to evaluate the lung ventilation in patients with oral corticosteroid-dependent bronchial asthma

“…2-15 Satoh et al reported the usefulness of Technegas SPECT to diagnose pulmonary emphysema. [12][13][14] In addition, Zhang et al reported that an index expressing the subliminal heterogeneous distribution by Technegas SPECT correlates well with the severity of silicosis. 15 There are however, no reports which evaluate the usefulness of Technegas to diagnose bronchial asthma.…”

“…Technegas [12][13][14] Technegas was generated in a proprietary generator (Technegas Generator, Tetley Manufacturing Ltd., Sydney, Australia) by the resistive heating of a graphite crucible up to 2,500°C in which a saline solution of 505 MBq of Tc-99m pertechnetate was added and then the mixture was dried. After Technegas was generated in an atmosphere of 100% argon, it was dispersed in a leadlined chamber.…”

Usefulness of 99mTc-Technegas and 133Xe dynamic SPECT in ventilatory impairment

“…On the other hand, as functional imaging, recently ultrafine 99m Tc-labelled carbon particles are being used for ventilation scintigraphy including single photon emission computed tomography (SPECT) [2][3][4][5][6][7][8][9][10][11][12]. Burch et al [2] reported that 99m Tc-Technegas (Technegas) has a considerably small particle size and can reach the peripheral parts of the lung.…”