BACKGROUND: Tumor therapy has been monitored using the metabolic indicator [18F]fluorodeoxyglucose ([18F]FDG). However, the nucleotide precursor [18F]fluoro-thymidine ([18F]FLT) is in principle more specific as it is incorporated into DNA. Thus, the [18F]FDG and [18F]FLT uptake by human neuroblastomas grown in Scid mice are compared in this study. MATERIALS AND METHODS: Scid mice were inoculated with human neuroblastoma cells. Tumor imaging was performed with a human whole-body full-ring PET scanner. Furthermore, the tumor weight and the cell proliferation rate were determined. RESULTS: Neuroblastomas could be visualised using [18F]FDG in 40% and with [18F]FLT in 70% of the cases. [18F]FDG or [18F]FLT uptake could not be visualised in neuroblastomas less than 1.0 g in weight. No correlation between the cell proliferation rate and tracer uptake could be detected. CONCLUSION: [18F]FLT showed a higher uptake than [18F]FDG and, therefore, might be more suitable for monitoring anticancer therapy, at least in this tumor model.
