Efficacy of malignant tumor detection with 0-(2-[^<18>F]fluoroethy1)-L-tyrosine (FET)

氨基酸示踪剂0-(2-[^&lt；18&gt；^F)]氟乙基-L-酪氨酸(FET)是近年来发展起来的一种氨基酸类似物，具有合成简单、放化产率高等优点。这项研究的目的是探讨FET的生物分布，并评价FET在恶性肿瘤诊断中的作用。C57BL/6小鼠为皮下注射。将1×106EL4细胞接种于含磷酸盐生理盐水的100μL液中。侧翼(肿瘤模型)。小鼠也是S.C.将100μL完全弗氏佐剂加入1t.肿瘤接种前4天和接种后3天侧翼(炎症模型)。肿瘤接种后7天，小鼠静脉注射。尾静脉注射37-185MBq FET。注射后，在几个时间点处死小鼠。在所有正常器官中，FET的积聚迅速增加，并在注射后30min内达到峰值，随后逐渐下降。胰腺的FET摄取率最高，约为其他器官的4倍。FET在肿瘤组织中的摄取明显高于其他器官和炎性病变。对4名正常志愿者进行FET治疗。动态分析表明，FET在正常器官中的积聚迅速增加，并在注射后5min内达到高峰。各器官的蓄积量逐渐减少，20min时达到高峰。FET给药60min后拍摄的静态图像显示，正常器官对FET的摄取几乎等于或略高于肌肉。这项研究表明，FET被认为是一种有用的肿瘤成像氨基酸示踪剂。它有可能区分肿瘤和炎症。

The amino acid tracer 0-(2-[^<18> ^F)] fluoroethy1) -L-tyrosine (FET) is a recently developed amino acid analogue, which can be synthesized easily with high radiochemical yield. The purposes of this study were to address the biodistribution of FET and to evaluate the usefulness of FET for the diagnosis of malignancy. C57BL/6 mice were s.c. inoculated with 1x106 EL4 cells in 100μL of PBS (phosphate based saline) into rt. flank (tumor model). Mice were also s.c. administrated 100μL of complete Freund's adjuvant (CFA) into 1t. flank 4 days before and 3 days after tumor inoculation (inflammation model). Seven days after tumor inoculation, mice were i.v. injected with 37-185 MBq FET via tail vein. After injection, mice were sacrificed on several time points. In all normal organs, FET accumulation rapidly increased and peaked within 30 min after the injection and afterward gradually decreased. The highest FET uptake was observed in pancreas and was about 4 times higher than other organs. The uptake of FET in the tumor tissue was significantly higher than other organs and inflammatory lesion. FET was administrated in four normal volunteers. Dynamic analysis showed that FET accumulation in normal organs increased rapidly and peaked within 5 min after the injection. The accumulation in organs were gradually decreased and reached a plateau at 20 min. Static images taken 60 min after FET administration showed that FET uptake in normal organs were nearly equal or slightly higher than that of muscle. This study shows that FET is considered to be a useful amino acid tracer for tumor imaging. It would have the potential to differentiate tumor from inflammation.