Introduction: The radiochemical 18F-2-deoxy-2-fluoro-D-glucose (18F-FDG), a positron emitter, is taken up preferentially by malignant tumors with high metabolic rates. This concentration of 18F-FDG in the tumor permits diagnosis and staging by positron emission tomography but also may represent a means of targeting radiotherapy. In this study, we determined the effect of a higher dose of 18F-FDG on tumor growth in a mouse model. Materials and methods: The effect of 18F-FDG on the growth and viability of 3 tumor cell lines was determined in vitro. Primary tumor growth and metastasis of B16/BL6 melanoma cells were determined in C57BL/6 mice injected with 5 mCi doses of 18F-FDG (2/3 doses). Results: 18F-FDG was cytostatic for all 3 cell lines at the lowest dose tested. It significantly reduced the growth of primary tumors, by 89% at day 19 postinoculation, and also almost totally inhibited the appearance of lung metastases after intravenous inoculation of the same cells. Conclusions: 18F-FDG proved to be an effective radiotherapeutic agent in this model. The possible problems associated with the accumulation of this radiochemical at other sites besides the tumor must be addressed.
