细菌显像剂18F-FDS的合成及动物显像应用研究

目的 探讨细菌显像剂2-脱氧-2-氟山梨醇(2-deoxy-2-18F]-fluorosorbitol, ¹⁸F-FDS)的合成过程、正常小鼠显像并计算内照射剂量,比较小鼠模型中大肠杆菌感染病灶及肿瘤病灶对FDS的摄取情况。方法 ¹⁸F-FDS由氟多功能模块经"一锅法"由PET常用显像剂2-氟-2脱氧葡萄糖(18F-fluorodeoxyglucose, ¹⁸F-FDG)经NaBH₄还原制备;实验组感染小鼠及荷瘤鼠尾静脉注射¹⁸F-FDS后60min进行microPET显像,通过Inveron Research软件测量病灶靶/本底比值;对照组注射¹⁸F-FDG,同样方法测量病灶靶/本底比值进行对照分析。结果 ¹⁸F-FDS放化收率为80%±5%(n=8,未进行时间衰减校正),合成时间25min,放化纯度>99%。正常小鼠尾静脉注射¹⁸F-FDS后microPET显像提示示踪剂从泌尿系统排泄;背景组织肺及脑内的非特异性放射性摄取较低;大肠杆菌感染小鼠microPET显像,感染灶有较高的感染灶/肌肉比值,荷瘤鼠显像示¹⁸F-FDS肿瘤组织靶/本底比值明显低于¹⁸F-FDG。结论 ¹⁸F-FDS放化合成方法操作简单,收率高,细菌感染灶有特异性摄取,在分辨感染和肿瘤上具有应用前景。

Radiosynthesis of Infection Tracer 18F-FDS and Animal Imaging

Objective To synthesis ¹⁸F-FDS from ¹⁸F-FDG, calculate internal radiation dose in normal mice imaging, look for the difference of FDS accumulated in E.coli infection mouse model and in tumor lesions. Methods ¹⁸F-FDS was synthesized on multifunctional synthesis module from ¹⁸F-FDG with sodium borohydride reduction by 'One-pot reaction'. In test group, ¹⁸F-FDS was injected into infection mice model and tumor mice model via tail vein for microPET imaging after 60min. T/B values of ¹⁸F-FDS were measured and analyzed by Inveron Research software. ¹⁸F-FDG was injected into model mice in control group and T/B values were measured as describe above for comparison. Results It took 25 min to complete ¹⁸F-FDS synthesis. The radiochemical yield and radiochemistry purity of ¹⁸F-FDS was 80%±5%, and over 99% respectively. MicroPET imaging data with normal mouse suggested that ¹⁸F-FDS was cleared from kidneys. The nonspecific uptake of ¹⁸F-FDS in background tissue such as lung, brain was very low. MicroPET imaging data showed that E. coli infected loci in mouse model had high T/B ratio, while tumor lesions had much lower T/B ratio. Conclusion ¹⁸F-FDS is easy to be prepared with high yield and can be used to trace bacteria infected loci specifically. It is a promising radiotracer for differentiated diagnosis of bacteria infection from tumor.