Objectives: Differentiation of infection from sterile inflammation is still a major concern for clinicians. The 18F-WBC positron emission tomography/computed tomography scan has been considered a promising tool for accurate diagnosis of infection owing to its high specificity, but it renders the availability of a medical cyclotron a necessity. The aim of the present study was to determine the feasibility of labeling leukocytes and establish the protocol in a center without the availability of an on-site medical cyclotron. The secondary aim was to monitor radiation doses to occupational workers involved in labeling of leukocytes with 18F-FDG. Materials and Methods: Leukocyte separation was performed and leukocytes were radiolabeled with 18F-FDG in a sterile environment according to the procedure described by Bhattacharya et al. In vitro leukocyte viability was assessed using the trypan dye exclusion technique. Labeling efficiency and yield were also estimated for all radiolabeling procedures. Whole-body and extremity doses received by the personnel involved in the radiolabeling procedure were also estimated using pocket dosimeters. Results: Leukocyte labeling was carried out in 35 runs, during which there were two failed labeling attempts due to clotting of the blood sample. The total time involved in the whole procedure was around 2.5 h. The average labeling efficiency was 78.01% ± 6.99% (range 63.46%-86.54%), cell viability was 98%, and the cell suspension was stable up to 4 h. The mean dose was measured as 17 μSv at the chest level and 32 μSv at the extremity level, per procedure. Conclusions: Labeling of leukocytes with 18F-FDG is possible at a tertiary nuclear medicine setup without the availability of an on-site medical cyclotron, with reasonable labeling efficiency of 78.01% ± 6.99%. In addition, in-house labeling of leukocytes with 18F-FDG is safe and the radiation doses incurred by the personnel during the labeling procedure are well within the occupational dose limits established by the national regulatory authority.
Keywords: 18F-FDG; 18F-FDG-leucocytes; infection; personnel monitoring.