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Tc-99m-N-MPO: Novel cationic Tc-99m radiotracer for myocardial perfusion imaging

Journal of Nuclear Cardiology volume 15, pages 535–546 (2008)Cite this article

Abstract

Background. Technetium 99m-N-MPO ([Tc-99m-N(mpo)(PNP5)]+) is a cationic Tc-99m nitrido complex. The objective of this study is to evaluate its potential as a new radiotracer for myocardial perfusion imaging.

Methods and Results. Biodistribution studies were performed in Sprague-Dawley rats and guinea pigs to compare the myocardial uptake and excretion kinetics of Tc-99m-N-MPO from noncardiac organs, such as the liver and lungs, with those of the known cationic Tc-99m radiotracers: Tc-99m-N-DBODC5 and Tc-99m-sestamibi. Planar imaging was performed in Sprague-Dawley rats to evaluate the utility of Tc-99m-N-MPO as a myocardial perfusion imaging agent. Metabolism studies were carried out by use of both Sprague-Dawley rats and guinea pigs. In general, the heart uptake of Tc-99m-N-MPO was between that of Tc-99msestamibi and Tc-99m-N-DBODC5 over the 2-hour study period. However, the heart-liver ratio of Tc-99m-N-MPO (12.75±3.34) at 30 minutes after injection was more than twice that of Tc-99m-N-DBODC5 (6.01±1.45) and approximately 4 times higher than that of Tc-99msestamibi (2.90±0.22). The heart uptake and heart-liver ratio of Tc-99m-N-MPO and Tc-99m-sestamibi in guinea pigs were significantly lower than those obtained in Sprague-Dawley rats. The metabolism studies demonstrated no detectable Tc-99m-N-MPO metabolites in the urine and feces samples of the Sprague-Dawley rats at 120 minutes after injection. In guinea pigs no Tc-99m-N-MPO metabolites were detected in the urine at 120 minutes, but only approximately 60% of Tc-99m-N-MPO remained intact in the feces samples. In contrast, there was no intact Tc-99m-sestamibi detected in urine samples, and less than 15% of Tc-99m-sestamibi remained intact in the feces samples. Planar imaging studies indicated that clinically useful images of the heart may be obtained as early as 15 minutes after injection of Tc-99m-N-MPO.

Conclusion. The combination of favorable organ biodistribution and myocardial uptake with rapid liver clearance makes Tc-99m-N-MPO a very promising myocardial perfusion radiotracer worthy of further evaluation in various preclinical animal models.

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Author notes

  1. Shuang Liu PhD

    Present address: School of Health Sciences, Purdue University, Civil Engineering Building, Room 1275, 550 Stadium Mall Dr, 47907, West Lafayette, IN

Affiliations

  1. School of Health Sciences, Purdue University, Civil Engineering Building, Room 1275, 550 Stadium Mall Dr, 47907, West Lafayette, IN

    Young-Seung Kim BS & Jianjun Wang PhD

  2. Experimental Nuclear Cardiology Laboratory, Department of Medicine, Cardiovascular Division, University of Virginia Health System, Charlottesville, Va.

    Alexis Broisat PhD & David K. Glover ME, PhD

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  1. Young-Seung Kim BS
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  2. Jianjun Wang PhD
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Additional information

This work was supported, in part, by Purdue University and the following research grants: R01 CA115883 A2 (S.L.) from the National Cancer Institute, BCTR0503947 (S.L.) from the Susan G. Komen Breast Cancer Foundation, AHA0555659Z (S.L.) from the Greater Midwest Affiliate of the American Heart Association, R21 EB003419-02 (S.L.) from the National Institute of Biomedical Imaging and Bioengineering, and R21 HL083961-01 from the National Heart, Lung, and Blood Institute.

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Kim, YS., Wang, J., Broisat, A. et al. Tc-99m-N-MPO: Novel cationic Tc-99m radiotracer for myocardial perfusion imaging. J Nucl Cardiol 15, 535–546 (2008). https://doi.org/10.1016/j.nuclcard.2008.02.022

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  • DOI: https://doi.org/10.1016/j.nuclcard.2008.02.022

Key Words

  • Cationic technetium 99m radiotracers
  • myocardial perfusion imaging