Indium-111-labeled leukocytes for the localization of abscesses: preparation, analysis, tissue distribution, and comparison with gallium-67 citrate in dogs.

Leukocytes have been labeled with indium-111-8-hydroxyquinoline complex. Seventy-five to 85 per cent of the initial activity has been obtained in the complex form of which 75 to 95 per cent is incorportaed with leukocytes. The polymophonuclear leukocytes are predominantly labeled, and the label has been found stable for at least 27 hours after invivo administration. The radioactivity clears from the circulating blood with a half time of 8 to 9-hours and accumulates in normal liver and spleen and in experimentally induced abscesses. The cells which have been labeled and damaged by heat concentrate mainly in the lungs. The in vivo distribution of the indium-111 labeled cells has been compared with the gallium-67 administered as citrate. The abscess to blood ratios of the indium-111 activity varied between 35 to 117, compared to 1.2 to 8 of the gallium-67. The abscess to liver, spleen, and kidney ratios are several fold higher with indium-111 leukocytes than with gallium=67 citrate. These results plus the suitable physical characteristics of indium-111 make the labeled leukocytes a better agent for the localization of abscesses.