@misc{oai:repo.qst.go.jp:00071217,
 author = {Mori, Tetsuya and Kobayashi, Masakazu and Kiyono, Yashushi and Furukawa, Takako and Fujibayashi, Yasuhisa and et.al and 古川 高子 and 藤林 康久},
 month = {Jun},
 note = {Objectives: F-18 labeled fluoroacetate (FA) has been developed as a PET tracer for imaging of oxidative metabolism in various tissues. For brain studies, however, the low blood-brain barrier (BBB) permeability of anionic form like FA is a fundamental problem. It is well known that ethyl acetate penetrates easily into the brain, then, is hydrolyzed to acetate rapidly in vivo. Based on these characteristics, we selected F-18 labeled ethyl fluoroacetate (EFA), ethyl-ester of FA, as a potential candidate for PET tracer of oxidative metabolism in brain. In this study, we investigated the possibility of [18F] EFA for brain PET imaging. Methods: BBB permeability was estimated by brain uptake index (BUI) method. Stability of [14C] EFA in plasma was assessed using five animal species. Then, the ester hydrolysis rate in rat brain was assayed both in vitro and in vivo. After these preliminary studies, we performed PET and metabolism studies of [18F] EFA using non-human primates.
 Results: The BUI of [14C] EFA was 125.9 +- 4.1% (n=4). This value was much higher than [14C] FA and also higher than that of [3H] H2O. The stability studies in plasma showed that [14C] EFA was extremely unstable in rodent, but stable in primate. Dog plasma brought an intermediate rate of degradation. The [14C] EFA was hydrolyzed rapidly in rat brain. These results suggest that EFA can be used as a pro-drug of [18F] FA for cerebral PET studies and the primate is suitable for in vivo experiments. In PET study using common marmosets, [18F] EFA showed higher brain uptake compared to [18F] FA at initial period, and the radioactivity was retained at 90 min after injection. The metabolism studies revealed that [18F] EFA was metabolized to only [18F] FA in arterial blood at 60 min after injection, but was converted to [18F] fluorocitrate in the brain, an intermediate metabolite from FA in the TCA cycle. 
Conclusions: we confirmed that [18F] EFA has ideal characteristics for brain imaging and it is a possible., Society of nuclear medicine 54rd Annual Meetng},
 title = {Development of [18F] ethyl fluoroacetate as a tracer of oxidative metabolism in the brain},
 year = {2007}
}