IN-VITRO EVALUATION OF WHITE BLOOD-CELL LABELING WITH 99TCM RADIOPHARMACEUTICALS

Several commercially available Tc-99(m) radiopharmaceuticals were test ed as possible white blood cell labelling agents. Labelling efficiency , labelling stability and white blood cell adherence were measured in vitro. White blood cells were not successfully labelled with mebrofeni n, disofenin, gluceptate or dimercaptosuccinic acid but were successfu lly labelled with exametazime, albumin colloid, sulphur colloid, sesta mibi and teboroxime. Exametazime had the highest mean labelling effici ency of 79%. Labelling efficiency was 5-14% with albumin colloid, sulp hur colloid, sestamibi and teboroxime. Labelling stability was high (> 95% at 4 h and >80% at 24 h) for all agents except sestamibi (52% at 4 h and 5% at 24 h). Exametazime did not alter white blood cell adheren ce. Albumin colloid, sestamibi and teboroxime decreased adherence and sulphur colloid increased adherence. Exametazime appears to be the bes t agent for labelling white blood cells. Teboroxime, however, is a new agent for labelling white blood cells which deserves further investig ation.