Abstract
1463
Objectives: 11C-acetate has been used as a probe of tumor detection through entry into anabolic pathways as mediated by acetyl-coenzyme A. However, the short half-life of 11C (20 min) limits its widespread usage in clinical PET applications. This study aimed to evaluate the fluorinated analog,18F-fluoroacetate (18F-FAc), as a PET probe for monitoring lung carcinoma and inflammation in a mouse model. Methods: Starting from ethyl bromoacetate, 18F-FAc was prepared by a two-step synthesis in 60 min with high yield (60%, decay corrected) and high radiochemical purity (≧98%). C57BL/6 mice were inoculated with 2×106 LLC1 lung carcinoma cells in the left flank on day 0 and then injected with 0.1 mL turpentine in the right flank subcutaneously on day 8. The biodistribution study and microPET imaging of 18F-FAc and 18F-FDG were performed on day 12 after tumor inoculation in the animals bearing tumor and inflammation. Results: The radioactivity in the blood cleared much slower for 18F-FAc than for 18F-FDG after tracers administration. For 18F-FAc, prominent accumulation of 18F-FAc in tumor, compared with all normal organs except the bone, was observed in the entire period of experiment. The radioactivity retained in the inflammation was also higher than most normal organs, but at a lesser extent to that of tumor. The tumor radioactivity reached maximum (7.16 ± 1.58 %ID/g) at 30 min post injection and declined with time (3.35 ± 2.52 %ID/g at 120 min). Progressive increase in bony uptake of radioactivity due to fast in vivo defluorination in rodents was clearly observed. The microPET imaging showed consistent results as those obtained from biodidtribution study. For 18F-FDG, the high radioactivity accumulation was observed in tumor, inflammation, brain and bone marrow. The PET imaging with 18F-FAc and 18F-FDG both delineate the tumor and also the vertebrae. Conclusions: The radioactivity accumulated in tumor and inflammation was higher than almost all normal organs except the bone after 18F-FAc injection. This study demonstrated that 18F-FAc is a very promising PET probe for detection of tumors and inflammatory tissue in our animal model.
- Society of Nuclear Medicine, Inc.