CFLFLF-PEG-HYNIC-^99mTc In Early Diagnosis Of Acute Osteomylitis

Objective To prepare cFLFLF-PEG-HYNIC-^99mTc which is high radiochemical purityand high specific activity in order to explore the binding characters of cFLFLF-PEG-HYNIC-99mTc which is affinitive to neutrophils in vitro and the value of cFLFLF-PEG-HYNIC-99mTc in early diagnosis of acute osteomyelitis.Methods①The radiochemical purity of cFLFLF-PEG-HYNIC-^99mTc was analyzed byinstant thin-layer chromatography （ITLC）;②A test of saturation of binding betweencFLFLF-PEG-HYNIC-^99mTc and neutrophils was carried out in order to investigate thebinding affinity between cFLFLF-PEG-HYNIC-^99mTc and neutrophils;③cFLFLF-PEG-HYNIC-99mTc was injected through tail vein into five rats on the5thday after introductionof AO. Biodistribution of cFLFLF-PEG-HYNIC-^99mTc was detected after the rats weresacrificed at1h post-injection;④The rats received cFLFLF-PEG-HYNIC-^99mTc or^99mTc-MDP （control and experimental group） injection through tail vein respectively forscintigraphic studies on the5th,10th and15th day after induction of AO. T/Bs wereanalyzed by statistical method.Results①The specific activity of cFLFLF-PEG-HYNIC-^99mTc was more than1.22×1013Bq/mmol.The radiochemical purity was more than95%;②The binding ofcFLFLF-PEG-HYNIC-^99mTc to human neutrophils wasHigh-affinity, binding parameters （Kd and Bmax） were15.48nmol/L and526500cpm,respectively;③HE staining and immunohistochemistry confirmed successful model ofacute osteomyelitis. Using the model, we found that cFLFLF-PEG-HYNIC-^99mTc had asignificant uptake in the infected site of the left tibia, aslo in the liver and kidneys.④on the5thday after introduction of AO, the T/B ratios of SD rats of experimental group injectedwith cFLFLF-PEG-HYNIC-^99mTc after1h was significantly higher than those of SD rats of experimental group injected with^99mTc-MDP after4h. There is a significant differencebetween them （t=13.81, P <0.001）.Conclusion The superiority of cFLFLF-PEG-HYNIC-^99mTc scintigraphy in earlydiagnosis of acute osteomyelitis is more than that of traditional imaging agent^99mTc-MDP sothat cFLFLF-PEG-HYNIC-^99mTc has potential application in the future.