Synthesis and evaluation of amino acid-based radiotracer 99m Tc-N4-AMT for breast cancer imaging


Purpose. This study was to develop an efficient synthesis of -9-9-mTc-O-[3-(1,4,8,11-tetraazabicyclohexadecane)-propyl]- -methyl tyrosine (-9-9-mTc-N4-AMT) and evaluate its potential in cancer imaging. Methods. N4-AMT was synthesized by reacting N4-oxalate and 3-bromopropyl AMT (N-BOC, ethyl ester). In vitro cellular uptake kinetics of -9-9-mTc-N4-AMT was assessed in rat mammary tumor cells. Tissue distribution of the radiotracer was determined in normal rats at 0.5-4h, while planar imaging was performed in mammary tumor-bearing rats at 30-120 min. Results. The total synthesis yield of N4-AMT was 14. Cellular uptake of -9-9-mTc-N4-AMT was significantly higher than that of -9-9-mTc-N4. Planar imaging revealed that -9-9-mTc-N4-AMT rendered greater tumor/muscle ratios than -9-9-mTc-N4. Conclusions. N4-AMT could be synthesized with a considerably high yield. Our in vitro and in vivo data suggest that -9-9-mTc-N4-AMT, a novel amino acid-based radiotracer, efficiently enters breast cancer cells, effectively distinguishes mammary tumors from normal tissues, and thus holds the promise for breast cancer imaging. Copyright 2011 Fan-Lin Kong et al.

Publication Title

Journal of Biomedicine and Biotechnology