[Physicochemical characterization and lung clearance of pertechnegas].

Pertechnegas, which is a variant of technegas, is an ultrafine carbon aerosol formed inside a technegas generator in the presence of 3% oxygen and 97% argon. The easy extractability of the pertechnegas in the phosphate buffered saline (PBS), the distribution seen in rats after intravenous injection of the pertechnegas and the results of the radiochromatography showed that the pertechnegas behaved like pertechnetate (TcO4-). In vivo study, the clearance half time (T1/2) of inhaled pertechnegas has shown no significant difference to that of TcO4- aerosol in 7 normal subjects. T1/2 of the pertechnegas was considerably faster in comparison with T1/2 of DTPA aerosol. However, T1/2 of the pertechnegas was more rapid in 6 smokers compared with T1/2 in 4 nonsmokers (p < 0.01), and was also increased in the upper lung field compared with the lower lung field (p < 0.01); these results closely correlate with those obtained with DTPA aerosol. Further study of the clearance of the pertechnegas in pulmonary diseases is required to assess clinical usefulness.