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Journal of Biomedicine and Biotechnology
Volume 2012, Article ID 671708, 9 pages
Research Article

Development of Tyrosine-Based Radiotracer 𝟗𝟗𝐦Tc-N4-Tyrosine for Breast Cancer Imaging

1Department of Experimental Diagnostic Imaging, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
2Department of Imaging Physics, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA

Received 11 November 2011; Accepted 13 December 2011

Academic Editor: Lie-Hang Shen

Copyright © 2012 Fan-Lin Kong et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The purpose of this study was to develop an efficient way to synthesize 99mTc-O-[3-(1,4,8,11-tetraazabicyclohexadecane)-propyl]-tyrosine (99mTc-N4-Tyrosine), a novel amino acid-based radiotracer, and evaluate its potential in breast cancer gamma imaging. Precursor N4-Tyrosine was synthesized using a 5-step procedure, and its total synthesis yield was 38%. It was successfully labeled with 99mTc with high radiochemical purity (>95%). Cellular uptake of 99mTc-N4-Tyrosine was much higher than that of 99mTc-N4 and the clinical gold standard 18F-2-deoxy-2-fluoro-glucose (18F-FDG) in rat breast tumor cells in vitro. Tissue uptake and dosimetry estimation in normal rats revealed that 99mTc-N4-Tyrosine could be safely administered to humans. Evaluation in breast tumor-bearing rats showed that although 99mTc-N4-Tyrosine appeared to be inferior to 18F-FDG in distinguishing breast tumor tissue from chemical-induced inflammatory tissue, it had high tumor-to-muscle uptake ratios and could detect breast tumors clearly by planar scintigraphic imaging. 99mTc-N4-Tyrosine could thus be a useful radiotracer for use in breast tumor diagnostic imaging.