摘要目的：利用PET-MF-2V-IT-I氟多功能合成模块自动化合成4-18F-氟代丁酸及其甲酯，并初步探讨其作为PET显像剂的可行性。方法前体4-溴代丁酸甲酯与18F－发生氟代反应，中间体4-18F-氟代丁酸甲酯用高压液相色谱法分离，收集保留时间在6．8～7．8 min的组分，将此组分与NaOH溶液于115℃下加热水解10 min，加入HCl调至中性，得到4-18F-氟代丁酸；稀释后过C18柱，再用20 ml注射用水清洗C18柱，0．5 ml乙醇洗脱后用生理盐水稀释，得到4-18F-氟代丁酸甲酯。分别目测两种产品的澄清度，精密试纸测定pH值、测定放射化学纯度和稳定性。正常小鼠尾静脉注射4-18F-氟代丁酸30 min后行micro PET显像。结果4-18F-氟代丁酸和4-18F-氟代丁酸甲酯的自动合成时间分别为40 min和20 min，放化收率分别为35%和50%（均未经时间校正）， pH值分别为6．5和7．1，产品放射化学纯度均>95%。二者均澄清无颗粒，室温放置30 min后均出现脱氟现象。正常小鼠micro PET显像结果显示，脊柱有明显的放射性浓聚，表明4-18F-氟代丁酸在体内脱氟，肠道亦有较高的放射性摄取。结论4-18F-氟代丁酸及其甲酯的合成方法操作简便，合成时间短，且放化收率也较高，但因其不稳定，不适合用作PET显像剂进行进一步研究。但小鼠micro PET显像结果提示，18F-氟代丁酸类似物在肠道疾病诊断中有潜在研究价值。

abstractsObjective To synthesize 4-[18F] fluorobutyric acid and its methyl ester automatically using PET-MF-2V-IT-I multifunction synthesizer and to evaluate their feasibility as PET imaging agents. Methods The precursor, methyl 4-bromobutyrate was fluorinated with 18F-. The intermediate, methyl 4-[18F] fluorobutyrate was separated by high pressure liquid chromatography. The components which retention time was from 6.8 to 7.8 min were collected. The components were heated with NaOH solution at 115℃for 10 min to hydrolyze, and then neutralized with HCl solution. The product, 4-[18F] fluorobutyric acid was obtained. The components were diluted and passed through a C18 cartridge, which was washed with 20 ml water then. The product, methyl 4-[18F] fluorobutyrate was obtained after 0.5 ml ethanol eluted the cartridge and was diluted with saline. The quality controls of both products were done. The clarity was tested visually, the pH value was tested with precise pH paper, and the radiochemical purity and stability were also measured. 4-[18F] fluorobutyric acid (7.4~11.1 MBq) was injected into the C57BL/J mice via tail vein for micro PET imaging at 30 min time-point. Results The whole synthetic procedure periods of 4-[18F] fluorobutyric acid and methyl 4-[18F] fluorobutyrate were 40 min and 20 min separately. The radiochemical yields of the two products were about 35%and 50%(both decay uncorrected) respectively. The pH values were 6.5 and 7.1. The radiochemical purities were both>95%. Both the product solutions were clear and no particles. Defluorination was observed in these two product solutions 0.5 h later at room temperature. The micro PET imaging showed that the uptake of spine was clearly, which indicated that the imaging agent was defluorinated in vivo, the uptake of intestine was also higher. Conclusion 4-[18F] fluorobutyric acid and its methyl ester could be automatically synthesized on PET-MF-2V-IT-I multifunction synthesizer simply and rapidly. The synthetic yield, radiochemical purity were high. But for their instabilities at room tempera-ture, the two agents were not suitable for further studies as PET imaging agents. But the micro PET imaging suggested the analogs of [18F] fluorobutyric acid may have its potential in diagnosis of intestinal diseases.