68Ga枸橼酸制备及炎症显像

目的 67Ga枸橼酸被应用于感染和炎症的定位闪烁显像,但因其核素半衰期长,临床上应用逐渐减少,而68Ga枸橼酸具有理想的半衰期.本研究将枸橼酸标记68 Ga,探讨68 Ga枸橼酸PET显像对细菌性感染检测的可行性.方法 直接将枸橼酸钠和68Ga混合,室温放置15min完成标记.将标记产物用生理盐水稀释,用薄层层析分析标记产物的放射性化学纯度.用PET观察68Ga枸橼酸在正常小鼠体内的生物分布变化.用金黄色葡萄球菌感染小鼠左腿腓肠肌,4天后尾静脉注射68Ga枸橼酸,注射后不同时间显像观察68Ga枸橼酸在炎症模型小鼠体内的生物分布变化.结果 68Ga枸橼酸的标记在15min内完成,标记率达到96％以上,不需要进一步纯化即可应用于PET显像.正常动物的PET显像表明,68 Ga枸橼酸主要分布于心脏,通过膀胱排泄.炎症模型小鼠的研究表明,随时间延长,68Ga枸橼酸的放射性在细菌感染处摄取逐渐增高.结论 用一种简单方法制备成68Ga枸橼酸,初步研究表明68Ga枸橼酸能够对小鼠金黄色葡萄球菌感染引起的炎症显像.

68 Ga Citrate Preparation and Inflammation Imaging

Objective Although 67Ga-citrate has been successfully used in scintigraphic imaging for locating infection and inflammation,the long physical half-life of 67 Ga limited the wide-spread application of this agent.In contrast,68 Ga citrate has ideal physical half-life.Here we prepare 68Ga citrate,and explore the possibility of detecting bacteria infection and inflammation with 68Ga citrate.Methods Sodium citrate （0.1mol/L,0.2ml） was added into newly eluted 68Ga （370MBq,0.6ml） with 0.05mol/L HCl from 68Ge/68Ga and incubated at room temperature for 15min.The labeled product was diluted with saline and loaded on ITLC-SG strips to determine the radiochemical purity.An infection was induced in female ICR mice by injecting Staph A in the right thigh muscle.68 Ga-Citrate （3.7 MBq/mouse） was injected intravenously and the PET images were acquired in normal mice and inflammation model mice at different time-points.Results 68Ga-citrate was labeled with ＞ 96％ yield and purity within 15min and can be used for PET imaging without further purification.In normal mice,68Ga-citrate visualized heart and excreted through bladder.68Ga-citrate uptake was increasingly higher at the infection lesion from 20min to 120min post injection.Conclusion 68Ga-citrate was prepared in a simplified method.The preliminary data showed that 68 Ga-citrate was capable of detecting inflammation caused by Staph A infection in mice.