Objective To synthesize 18F-AlF-1,4,7-triazacyclononane-l,4,7-triacetic acid (NOTA)-c (CGRRAGGSC),which could specifically bind to the α chain of interleukin (IL)-11 receptor (IL-11 R),and evaluate its targeting potential to IL-11 R-positive tumors.Methods Polypeptide c (CGRRAGGSC) was first coupled with NOTA and then labeled with 18F by AlF labeling method.The radiochemical purity and radiochemical yield of 18F-AlF-NOTA-c(CGRRAGGSC) were analyzed by high performance liquid chromatography,and the stability in vitro was evaluated.The tracer biodistribution in tumor-bearing mice (cell line SKOV3) was evaluated by the dynamic imaging with microPET 30 min,1 h,2 h after injection of 18F-AlF-NOTA-c (CGRRAGGSC).The tracer kinetics was performed in normal mice.Pharmacokinetics parameters were calculated using DAS2.0 software.Results The radiochemical purity of 18F-AlF-NOTA-c(CGRRAGGSC) was higher than 95％ and the radiochemical yield was (30.0±7.4)％.It could be stably maintained in phosphatebuffered solution and plasma for at least 2 h.MicroPET imaging showed that 18F-AlF-NOTA-c(CGRRAGGSC)had a good affinity to SKOV3 tumor.The tumor/muscle ratios at 30 min,1 h,2 h after the injection of 18F-AlF-NOTA-c(CGRRAGGSC) were 6.26±2.98,7.19±3.63 and 9.05±4.30,respectively.The tracer was cleared rapidly in blood and mainly excreted by the liver and kidneys.The T1/2α and T1/2β were (0.38±0.14) h and (2.64±0.28) h,respectively.Conclusions 18F-AlF-NOTA-c(CGRRAGGSC) is easy to be synthesized and has a good affinity to IL-11R-positive tumors.It will be a potential IL-11R-targeting imaging agent.