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渡邉 茂樹
no journal, ,
Br (half-life = 16.1 h) is an attractive radionuclide for PET imaging, because its half-life is long enough to trace in vivo behavior of biologically active molecule. We have produced Br by using an AVF cyclotron at JAEA, and synthesized some radiobrominated compounds, Br-MBBG, a PET imaging reagent for norepinephrine transporter expressing tumors, and Br-BAMT, an amino acid tracer for imaging of various tumors. Synthesis and biological evaluations of these PET reagents will be reported in the symposium, and recent studies on radiobromination in JAEA will be also discussed.
大島 康宏; 花岡 宏史*; 富永 英之*; 金井 好克*; 解良 恭一*; 山口 藍子*; 永森 收志*; 織内 昇*; 対馬 義人*; 遠藤 啓吾*; et al.
no journal, ,
3-[F]Fluoro--methyl-L-tyrosine (L-[F]FAMT) is a useful amino acid tracer, and it is selectively accumulated in the tumor without an incorporation in the protein synthesis. However, L-[F]FAMT is highly retained in the kidney, which causes the reduction of sensitivity for tumor detection by positron emission tomography (PET). L-amino acids have corresponding D-isomers which have some favorable properties for development of PET tracers. Since mammals rarely use D-amino acids for their biological activity, D-amino acids would not be taken up by the normal tissues. In addition, D-amino acids are highly excreted in the urine compared with L-isomers, and rapidly cleared from the circulation. Thus, D-isomer of FAMT would lower the high retention of L-isomer in the kidney and allow clear imaging of the tumor by PET. In this study, we synthesized 3-[F]fluoro--methyl-D-tyrosine (D-[F]FAMT) and evaluated its potential. In biodistribution studies, D-[F]FAMT showed rapid clearance from blood, marked accumulation and retention in the tumor and low retention in non-target organs, especially kidney. Furthermore, PET imaging using D-[F]FAMT enabled clear visualization of implanted tumor, compared with L-[F]FAMT. In conclusion, D-[F]FAMT could potentially serve as a useful tracer for imaging malignant tumors.