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Development of tyrosine-based radiotracer 99mTc-N4-Tyrosine for breast cancer imaging.

Kong FL, Ali MS, Rollo A, Smith DL, Zhang Y, Yu DF, Yang DJ - J. Biomed. Biotechnol. (2012)

Bottom Line: The purpose of this study was to develop an efficient way to synthesize (99m)Tc-O-[3-(1,4,8,11-tetraazabicyclohexadecane)-propyl]-tyrosine ((99m)Tc-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 (99m)Tc with high radiochemical purity (>95%).

View Article: PubMed Central - PubMed

Affiliation: Department of Experimental Diagnostic Imaging, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA. kongfanlin2007@gmail.com

ABSTRACT
The purpose of this study was to develop an efficient way to synthesize (99m)Tc-O-[3-(1,4,8,11-tetraazabicyclohexadecane)-propyl]-tyrosine ((99m)Tc-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 (99m)Tc with high radiochemical purity (>95%). Cellular uptake of (99m)Tc-N4-Tyrosine was much higher than that of (99m)Tc-N4 and the clinical gold standard (18)F-2-deoxy-2-fluoro-glucose ((18)F-FDG) in rat breast tumor cells in vitro. Tissue uptake and dosimetry estimation in normal rats revealed that (99m)Tc-N4-Tyrosine could be safely administered to humans. Evaluation in breast tumor-bearing rats showed that although (99m)Tc-N4-Tyrosine appeared to be inferior to (18)F-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. (99m)Tc-N4-Tyrosine could thus be a useful radiotracer for use in breast tumor diagnostic imaging.

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The selected planar scintigraphic images of breast tumor- and inflammation-bearing rats at 30, 120, and 240 minutes after 99mTc-N4-Tyrosine injection and micro-PET images at 30, 60, and 90 minutes after 18F-FDG injection (T indicates tumor; I, inflammation). Tumor-to-muscle (T/M), inflammation-to-muscle (I/M), and tumor-to-inflammation (T/I) ratios are shown in the tables.
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fig6: The selected planar scintigraphic images of breast tumor- and inflammation-bearing rats at 30, 120, and 240 minutes after 99mTc-N4-Tyrosine injection and micro-PET images at 30, 60, and 90 minutes after 18F-FDG injection (T indicates tumor; I, inflammation). Tumor-to-muscle (T/M), inflammation-to-muscle (I/M), and tumor-to-inflammation (T/I) ratios are shown in the tables.

Mentions: The selected planar scintigraphic images of breast tumor- and inflammation-bearing rats at 30, 120, and 240 minutes after 99mTc-N4-Tyrosine injection, as well as micro-PET images at 30, 60, and 90 minutes after 18F-FDG injection, are shown in Figure 6. The T/M ratio of 99mTc-N4-Tyrosine was relatively higher than I/M ratio at each time point. Although T/I ratios were greater than 1 at all time points for both 99mTc-N4-Tyrosine and 18F-DFG, indicating that the tumor had higher uptake than the inflammation site, the T/I ratios for 99mTc-N4-Tyrosine were lower than those for 18F-FDG. This suggests that 99mTc-N4-Tyrosine was inferior to 18F-FDG in differentiating tumor from inflammation in this breast tumor-bearing rat model. However, we used turpentine to induce inflammation chemically in this model. It may be worth testing 99mTc-N4-Tyrosine in another animal model using radiation to induce inflammation so that the model better mimics patients undergoing radiation therapy.


Development of tyrosine-based radiotracer 99mTc-N4-Tyrosine for breast cancer imaging.

Kong FL, Ali MS, Rollo A, Smith DL, Zhang Y, Yu DF, Yang DJ - J. Biomed. Biotechnol. (2012)

The selected planar scintigraphic images of breast tumor- and inflammation-bearing rats at 30, 120, and 240 minutes after 99mTc-N4-Tyrosine injection and micro-PET images at 30, 60, and 90 minutes after 18F-FDG injection (T indicates tumor; I, inflammation). Tumor-to-muscle (T/M), inflammation-to-muscle (I/M), and tumor-to-inflammation (T/I) ratios are shown in the tables.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3303751&req=5

fig6: The selected planar scintigraphic images of breast tumor- and inflammation-bearing rats at 30, 120, and 240 minutes after 99mTc-N4-Tyrosine injection and micro-PET images at 30, 60, and 90 minutes after 18F-FDG injection (T indicates tumor; I, inflammation). Tumor-to-muscle (T/M), inflammation-to-muscle (I/M), and tumor-to-inflammation (T/I) ratios are shown in the tables.
Mentions: The selected planar scintigraphic images of breast tumor- and inflammation-bearing rats at 30, 120, and 240 minutes after 99mTc-N4-Tyrosine injection, as well as micro-PET images at 30, 60, and 90 minutes after 18F-FDG injection, are shown in Figure 6. The T/M ratio of 99mTc-N4-Tyrosine was relatively higher than I/M ratio at each time point. Although T/I ratios were greater than 1 at all time points for both 99mTc-N4-Tyrosine and 18F-DFG, indicating that the tumor had higher uptake than the inflammation site, the T/I ratios for 99mTc-N4-Tyrosine were lower than those for 18F-FDG. This suggests that 99mTc-N4-Tyrosine was inferior to 18F-FDG in differentiating tumor from inflammation in this breast tumor-bearing rat model. However, we used turpentine to induce inflammation chemically in this model. It may be worth testing 99mTc-N4-Tyrosine in another animal model using radiation to induce inflammation so that the model better mimics patients undergoing radiation therapy.

Bottom Line: The purpose of this study was to develop an efficient way to synthesize (99m)Tc-O-[3-(1,4,8,11-tetraazabicyclohexadecane)-propyl]-tyrosine ((99m)Tc-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 (99m)Tc with high radiochemical purity (>95%).

View Article: PubMed Central - PubMed

Affiliation: Department of Experimental Diagnostic Imaging, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA. kongfanlin2007@gmail.com

ABSTRACT
The purpose of this study was to develop an efficient way to synthesize (99m)Tc-O-[3-(1,4,8,11-tetraazabicyclohexadecane)-propyl]-tyrosine ((99m)Tc-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 (99m)Tc with high radiochemical purity (>95%). Cellular uptake of (99m)Tc-N4-Tyrosine was much higher than that of (99m)Tc-N4 and the clinical gold standard (18)F-2-deoxy-2-fluoro-glucose ((18)F-FDG) in rat breast tumor cells in vitro. Tissue uptake and dosimetry estimation in normal rats revealed that (99m)Tc-N4-Tyrosine could be safely administered to humans. Evaluation in breast tumor-bearing rats showed that although (99m)Tc-N4-Tyrosine appeared to be inferior to (18)F-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. (99m)Tc-N4-Tyrosine could thus be a useful radiotracer for use in breast tumor diagnostic imaging.

Show MeSH
Related in: MedlinePlus