IN-111-OXINE-LABELED GRANULOCYTE DOSIMETRY IN NORMAL SUBJECTS

The aim of this study was to determine organ uptake and dosimetry in h uman subjects using In-111 granulocytes obtained by ficoll-hypaque pur ification. Anterior-posterior whole-body imaging was performed at 1, 3 , 5, 24 and 48 h after injection of approximately 18.5 MBq (0.5 mCi) I n-111 granulocytes in 10 normal volunteers. Utilizing relative geometr ic mean analysis, the fraction of injected activity (FIA) was determin ed at each imaging time for the kidney, liver, lungs, bone marrow, spl een and whole-body remainder. Residence time was determined by integra tion of the bi-exponential fit of the FIA data over time. Curve fittin g was performed with SAAM software (University of Washington). Red mar row uptake was calculated from activity in the L3-L4 vertebrae and ili ac crests. Total body marrow uptake was extrapolated from these data u sing ICRP 23. Dose was determined with MIRDOSE 2 for the various organ s. The liver had the highest organ uptake (40.3% at 48 h). The spleen, liver, red marrow, kidney and lung doses were 4.1, 1.6, 0.8, 0.5 and 0.4 mGy MBq(-1), respectively. Urinary and stool excretion was negligi ble and blood clearance half-time was 6.9 h. Using current methods pro viding improved quantification of organ uptake and dosimetry, our resu lts confirm the liver, spleen, bone marrow, lungs and kidneys to be th e principal target organs of In-111 granulocytes.