Characterization of Different Osteosarcoma Phenotypes by PET Imaging in Preclinical Animal Models

The aim of this study was to characterize the different phenotypes of osteosarcoma by PET, comparing the uptake of 3 tracers (18F-FDG, 18F-fluoromisonidazole [18F-FMISO], and 18F-fluoride) in pre-clinical mouse models that reflect the heterogeneity of the human disease. Methods: Mouse LM8 osteosarcoma, human 143B, and Caprin-1 stably overexpressing SaOS-2 cells were injected intra-tibially in C3H and severe-combined immunodeficient mice. PET imaging with 18F-FDG, 18F-FMISO, and 18F-fluoride was performed in these mouse models, and a ratio between the standardized up-take value of the primary tumor and a control area of bone was calculated and compared among the models. Histology and immu-nohistochemistry were performed to confirm the PET findings. Results: The pattern of tracer uptake differed among the primary tumors of the 3 models in accordance with the histology and im-munohistochemistry on primary tumor sections. The osteolytic tu