Abstract
1447
Objectives: 2-Deoxy-2-18F-fluoro-D-glucose (FDG) was generally considered a sensitive but not specific probe for tumor imaging. 18F-Fluoromisonidazole (FMISO) and 18F-fluoroacetate (FAc) were also applied as tumor imaging agents for types of cancer. Accumulation of FDG in inflammatory lesion was well documented, while that of FMISO and FAc was not. This study investigated the biodistribution of the three tracers and evaluated their specificity toward tumor in a sarcoma- and inflammatory lesion-bearing mouse model. Methods: C3H mice were inoculated with 2×105 KHT sarcoma cells in the right thigh on day 0. Turpentine oil (0.1 mL) was injected in the left thigh on day 11. Biodistribution, pharmacokinetics and microPET imaging of the three tracers were performed on day 14 after tumor inoculation. Results: The inflammatory lesion was clearly visualized by FDG/microPET and autoradiography at 3 days after turpentine oil injection. Derived from microPET images, the tumor-to-muscle (Tu/Mu) and inflammatory lesion-to-muscle (Inf/Mu) ratios were 8.13 and 4.66 for FDG (n=3), 6.93 and 1.53 for FMISO (n=6), and 3.80 and 3.25 for FAc (n=6) at 4 h post injection. Among these, the tumor-to-inflammatory lesion ratio was highest for FMISO (4.63) compared with that of FDG (1.75) and FAc (1.18). The distribution half-life (t½α) and the elimination half-life (t½β) were 0.09 h and 1.08 h for FMISO, 0.05 h and 5.05 h for FDG, and 0.15 h and 11.33 h for FAc in mice. The area under curve (AUC) of blood is 11.78, 12.41 and 116.23 h × %ID/g for FMISO, FDG and FAc, indicated the highest bioavailability of FAc among these tracers in mice. Conclusions: MicroPET images showed that FDG and FAc delineated both tumor and inflammatory lesion while FMISO accumulated in tumor significantly higher than that in inflammatory lesion at 4 h post injection. The uptake of FMISO in inflammatory lesions is lowest among these tracers. Our results demonstrated the potential of FMISO in distinguishing tumor from inflammatory lesion in a mouse model.
- Society of Nuclear Medicine, Inc.