[Sequential scintigraphy of four different 99mTc human albumen preparations used for lung scanning]

The biological behaviour of four 99mTc-marked human albumen preparations, prepared by different methods, were studied by serial scintigraphy and excretion measurements. Three preparations consisted of particles of irregular albumen macroaggregates, the fourth was in the form of spherical albumen particles (microspheres). Forty-five patients with various pulmonary abnormalities were examined. The following parameters were used for comparison: half-life of pulmonary activity, changes in activity in liver and spleen as a measure for the formation of Tc-containing particle fragments, uptake in the thyroid and stomach and urinary excretion as an indication of the stability of the nucleid fixation. Despite marked differences in their biological behaviour, all four substances provide comparable information and lack of toxicity and are suitable for lung scintigraphy. Because of the rapid initial decline in activity in the lung, microspheres are more suitable for use with a gamma camera, whereas the other three preparations, in view of their long persistence in the lung can be conveniently used for the slower examinations with a conventional scanner.