PLATELET RADIOLABELING WITH (111)INDIUM FOR IN-VIVO STUDIES - A METHODOLOGICAL REAPPRAISAL

Two ligands widely used for In-111 labelling of human platelets, oxine and tropolone, were compared as to the degree of their influence on platelet function. The labelling efficiency was assessed as a function of experimental variables. A good preservation of platelet function as evaluated by ex vivo aggregation was obtained with both techniques. The extent of tracer detached from platelets was evaluated in vitro and in vivo: in normal subjects In-111 was virtually all bound to platelets. A significant reduction in radiolabelling efficiency and a decreased percentage of In-111 bound to platelets in vivo was observed in patients with platelet counts <150,000/mL.