Biodistribution and dosimetry of [F]fluorodeoxyglucose labelled leukocytes in normal human subjects

This study was performed in order to assess [F]fluorodeoxyglucose white blood cell (F-FDG WBC) dosimetry in normal human subjects. Using previously reported methods, mixed cell suspensions of autologous leukocytes were prepared from four normal volunteers. Leukocytes were labelled in heparin-saline by incubation with F-FDG at 37°C for 20 min. After washing and resuspension, F-FDG WBCs (225-315 MBq) were administered by intravenous injection. Whole-body imaging was performed at 0.5, 1, 2, 4 and 6 h using a GE Varicam with 511 keV collimation. Blood samples were obtained at corresponding times as well as fractionated urinary collection. Whole-body anterior and posterior images were used for calculation of organ dosimetry. Uptake of F-FDG WBCs occurred predominantly within the reticulo-endothelial system. Plasma activity, urinary excretion (9.9±2.3% at 6 h), and brain uptake (1.7±0.4%) were consistent with partial elution of F-FDG. Positron emission tomography imaging performed at5-6 h after injection yielded good quality images of reticulo-endothelial uptake. Whole-body and organ dosimetry for F-FDG WBCs in doses of 225-250 MBq are comparable with reported results for conventional doses of In oxine labelled leukocytes. Further studies of F-FDG WBC as an agent for positron emission tomography imaging of inflammatory disease appear warranted.