SYNTHESIS AND BIODISTRIBUTION OF O-(3-~(18)F-FLUOROPROPYL)-L-TYROSINE

O(318Ffluoropropyl)Ltyrosine (FPT) as an amino acid tracer for tumors imaging with positron emission tomography (PET) is prepared by a twostep procedure.Firstly,nucleophilic fluorination reaction of 18Ffluoride with 1,3di(4methylphenylsulfonyloxy)propane (TsOCH2CH2CH2OTs) yields 318F1(4methylphenylsulfonyloxy) propane(TsOCH2CH2CH218F),then 18Ffluoroalkylation of Ltyrosine disodium salt with TsOCH2CH2CH2 18F yields FPT.The overall radiochemical yield with no decay correction is 25%～30%,the whole synthesis time is about 70 min,and the radiochemical purity is above 95%.Biodistribution of FPT in normal mice,carcinomabearing nude mice and inflammatory mice,and PET imaging for nude mice bearing human Hep G2 liver cell carcinoma are performed.High uptake and longer retention of FPT in kidney,liver,lung and blood,and low uptake in brain are found.Also,high uptake of FPT in tumor and low uptake of FPT in inflammatory tissue are observed.FPT PET imaging allows a clear delineation of nude mice bearing carcinoma,and tumorliver ratio about 1.3 after 180 min postinjection is found.FPT is easy to prepare and can be used to differentiate between tumor and inflammatory tissue.It could become seem an amino acid tracer for tumors with PET imaging.