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Objective: Angiogenesis plays a critical role in tumor formation and metastasis.Recombinant human plasminogen kringle5 (rhk5) is a low molecular weight protein (14KD), which has a potent antiangiogenetic effect.Suitable radiolabeled angiogenesis inhibitor can be used for noninvasive imaging of angiogenesis and radionuclide therapy.Here we prepare the rhenium-188 (188Re)-rhk5 in a convenient manner and to evaluate its properties as an agent for A549 tumors.Methods: Radiolabeled rhk5 was obtained by conjugating the His group at the C end of rhk5 with fac-[188Re(H2O)3(CO)3]+.Chelating efficiency of fac-[188Re(H2O)3(CO)3]+ and radiolabeling efficiency of radiolabeled rhk5 were measured by radio thin-layer chromatography (RTLC).In vitro stability of 188Re-rhk5 was determined in human serum at 37℃ and analyzed by RTLC.Competition test was also performed to verify the specificity of binding.A biodistribution study was carried out in nude mice bearing A549 tumors.Results: 188Re-rhk5 was obtained with a radiolabel efficiency of 66.1%, the radiochemical purity (RCP) can reach 95.2% after purification.188Re-rhk5 showed high stability in human serum, the RCP was more than 80% even 12 h after incubation.Competition test showed a high binding specificity.Furthermore, this radio-complex was excreted mainly through kidneys and showed specific tumor uptake in mice bearing A549 tumors.Conclusions: 188Re-rhk5 was prepared by a simple method.Preliminary biodistribution results showed its potential as an agent for tumor imaging and encouraged further investigation.