[18F]FDG WBC labelled PET/CT for the diagnosis of infectious disease: initial experience in a tertiary centre

Labelling WBC with [18F]FDG may be an alternative for accurate infection diagnosis, combining the excellent sensitivity of [18F]FDG with the excellent specificity of WBC-labelled SPECT/CT. We aim to investigate the feasibility, safety and accuracy of [18F]FDG-labelled WBC in patients with suspected infectious disease. Scans were performed at 131 ± 13 min and 201 ± 16 min after [18F]FDG-labelled WBC administration. 14 identified lesions were follow-up. [18F]FDG-labelled WBC PET/CT yielded a sensitivity / specificity of 82% / 100%. False negative lesions were localized in axial and proximal skeleton. SUVmax@2h and SUVmax@3h for infected lesions were 10.4 ± 8.8 and 13.9 ± 12.3. aSUV and rSUV values for infected lesions were 3.5 ± 4.3 and 34.2 ± 29.1 Radiolabelling efficiency was 74.8 ± 19.4% (84.9 ± 5.34% vs. 57.9 ± 22.3%, p < 0.025 in diabetic vs. non-diabetic). The dose to the operator were 39.3 ± 11.8 µSv for the axial body and 69.1 ± 26.2 µSv for the extremities. Assessing the dynamic of [18F]FDG-labelled WBC is feasible and yielded a very good diagnostic performance, however with some limitation for lesion of the axial skeleton and the reticuloendothelial system. Moreover, the procedure is operator and patient safe. Improvement in shielding during radiolabelling as well as further investigations with larger population are still needed.