Study on intra tumor distribution of 18F(14C)-labeled FDG in mouse fibrosarcoma

An early image of intra-tumor distribution of 14C-labeled fluorodeoxyglucose (14C-FDG) was compared with late image obtained by 18F-labeled FDG (18F-FDG) in the same animal (C3H mice) using dual tracer autoradiography. Heterogeneous intra-tumor distribution of 14C-FDG was observed 1 min post injection of the tracer, whereas relatively homogeneous distribution of 18F-FDG was seen at 30 minutes later. 14C-FDG was particularly taken up in peripheral part of tumor immediately after the tracer injection. A gradual and significant increase in 18F-FDG accumulation with time was seen in central part of tumor, which indicated enhancement of anaerobic glycolysis. An initial uptake of 18F-FDG in fibrosarcoma was also compared with regional blood flow by a dual tracer method. A similar regional distribution of 14C-idoantyprine as that of initial uptake of 18F-FDG was observed. These results supported that the central area of fibrosarcoma might be a hypoxic region. To compare the early image of 18F-FDG to late image seems to have some value for evaluation of hypoxia in solid tumor. (author)