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Boschi A, Uccelli L, Marvelli L, Cittanti C, Giganti M, Martini P. Technetium-99m Radiopharmaceuticals for Ideal Myocardial Perfusion Imaging: Lost and Found Opportunities. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27041188. [PMID: 35208982 PMCID: PMC8877792 DOI: 10.3390/molecules27041188] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 02/06/2022] [Accepted: 02/08/2022] [Indexed: 02/07/2023]
Abstract
The favorable nuclear properties in combination with the rich coordination chemistry make technetium-99m the radioisotope of choice for the development of myocardial perfusion tracers. In the early 1980s, [99mTc]Tc-Sestamibi, [99mTc]Tc-Tetrofosmin, and [99mTc]Tc-Teboroxime were approved as commercial radiopharmaceuticals for myocardial perfusion imaging in nuclear cardiology. Despite its peculiar properties, the clinical use of [99mTc]Tc-Teboroxime was quickly abandoned due to its rapid myocardial washout. Despite their widespread clinical applications, both [99mTc]Tc-Sestamibi and [99mTc]Tc-Tetrofosmin do not meet the requirements of an ideal perfusion imaging agent due to their relatively low first-pass extraction fraction and high liver absorption. An ideal radiotracer for myocardial perfusion imaging should have a high myocardial uptake; a high and stable target-to-background ratio with low uptake in the lungs, liver, stomach during the image acquisition period; a high first-pass myocardial extraction fraction and very rapid blood clearance; and a linear relationship between radiotracer myocardial uptake and coronary blood flow. Although it is difficult to reconcile all these properties in a single tracer, scientific research in the field has always channeled its efforts in the development of molecules that are able to meet the characteristics of ideality as much as possible. This short review summarizes the developments in 99mTc myocardial perfusion tracers, which are able to fulfill hitherto unmet medical needs and serve a large population of patients with heart disease, and underlines their strengths and weaknesses, the lost and found opportunities thanks to the developments of the new ultrafast SPECT technologies.
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Affiliation(s)
- Alessandra Boschi
- Department of Chemical, Pharmaceutical and Agricultural Sciences, University of Ferrara, Via L. Borsari, 46-44121 Ferrara, Italy;
- Correspondence: ; Tel.:+39-0532-455354
| | - Licia Uccelli
- Department of Translational Medicine, University of Ferrara, Via Fossato di Mortara, 70 c/o Viale Eliporto, 46-44121 Ferrara, Italy; (L.U.); (C.C.); (M.G.)
| | - Lorenza Marvelli
- Department of Chemical, Pharmaceutical and Agricultural Sciences, University of Ferrara, Via L. Borsari, 46-44121 Ferrara, Italy;
| | - Corrado Cittanti
- Department of Translational Medicine, University of Ferrara, Via Fossato di Mortara, 70 c/o Viale Eliporto, 46-44121 Ferrara, Italy; (L.U.); (C.C.); (M.G.)
| | - Melchiore Giganti
- Department of Translational Medicine, University of Ferrara, Via Fossato di Mortara, 70 c/o Viale Eliporto, 46-44121 Ferrara, Italy; (L.U.); (C.C.); (M.G.)
| | - Petra Martini
- Department of Environmental and Prevention Sciences, University of Ferrara, Via L. Borsari, 46-44121 Ferrara, Italy;
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Klein R, Celiker-Guler E, Rotstein BH, deKemp RA. PET and SPECT Tracers for Myocardial Perfusion Imaging. Semin Nucl Med 2020; 50:208-218. [PMID: 32284107 DOI: 10.1053/j.semnuclmed.2020.02.016] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Coronary artery disease has been the leading cause of death since the 1960s, which has motivated the research and development of myocardial perfusion imaging (MPI) agents for early diagnosis and to guide treatment. MPI with SPECT has been the clinical workhorse for MPI, but over the past two decades PET MPI is experiencing growth due to enhanced image quality that results in superior diagnostic accuracy over SPECT. Furthermore, dynamic PET imaging of the tracer distribution process from time of tracer administration to tracer accumulation in the myocardium has enabled routine quantification of myocardial blood flow (MBF) and myocardial flow reserve (MFR) in absolute units. MBF and MFR incrementally improve diagnostic and prognostic accuracy over MPI alone. In some cases (eg, rubidium PET imaging with pharmacologic stress) MPI, MBF, and MFR can be acquired simultaneously without incremental cost, radiation exposure, or significant processing time. Nuclear cardiology clinics have been looking to incorporate MBF quantification into clinical routine, but traditional SPECT and MPI tracers are inadequate for this challenge. Cardiac dedicated SPECT scanners can also perform dynamic imaging and have stimulated research into MBF quantification using SPECT tracers. New perfusion tracers must be tailored for emerging clinical needs (including MBF quantification), technical capabilities of imaging instrumentation, market constraints, and supply chain feasibility. Because these conditions have been evolving, tracers previously considered inferior may be reconsidered for future applications and some recently developed tracers may be suboptimal. This article reviews current, clinically-available tracers and those under development showing greatest potential. It discusses for each tracer the rationale for development, physiological mechanism of uptake by the myocardium, published evaluation results and development state. Finally, it gauges the suitability of each tracer for clinical application. The article demonstrates an acceleration in the pace of perfusion radiotracer development due to better understanding of the relevant physiology, better chemistry tools and small animal imaging. Consequently, bad tracers may fail faster and with less wasted investment, and good tracers may translate more efficiently from bench to bedside.
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Affiliation(s)
- Ran Klein
- University of Ottawa Heart Institute, Division of Cardiology, Ottawa, ON, Canada; The Ottawa Hospital, Division of Nuclear Medicine, Ottawa, ON, Canada
| | - Emel Celiker-Guler
- University of Ottawa Heart Institute, Division of Cardiology, Ottawa, ON, Canada
| | - Benjamin H Rotstein
- University of Ottawa Heart Institute, Division of Cardiology, Ottawa, ON, Canada; Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON, Canada
| | - Robert A deKemp
- University of Ottawa Heart Institute, Division of Cardiology, Ottawa, ON, Canada.
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MacPherson DS, Fung K, Cook BE, Francesconi LC, Zeglis BM. A brief overview of metal complexes as nuclear imaging agents. Dalton Trans 2020; 48:14547-14565. [PMID: 31556418 DOI: 10.1039/c9dt03039e] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Metallic radionuclides have been instrumental in the field of nuclear imaging for over half a century. While recent years have played witness to a dramatic rise in the use of radiometals as labels for chelator-bearing biomolecules, imaging agents based solely on coordination compounds of radiometals have long played a critical role in the discipline as well. In this work, we seek to provide a brief overview of metal complex-based radiopharmaceuticals for positron emission tomography (PET) and single photon emission computed tomography (SPECT). More specifically, we have focused on imaging agents in which the metal complex itself rather than a pendant biomolecule or targeting moiety is responsible for the in vivo behavior of the tracer. This family of compounds contains metal complexes based on an array of different nuclides as well as probes that have been used for the imaging of a variety of pathologies, including infection, inflammation, cancer, and heart disease. Indeed, two of the defining traits of transition metal complexes-modularity and redox chemistry-have both been creatively leveraged in the development of imaging agents. In light of our audience, particular attention is paid to structure and mechanism, though clinical data is addressed as well. Ultimately, it is our hope that this review will not only educate readers about some of the seminal work performed in this space over the last 30 years but also spur renewed interest in the creation of radiopharmaceuticals based on small metal complexes.
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Affiliation(s)
- Douglas S MacPherson
- Department of Chemistry, Hunter College of the City University of New York, New York, NY 10028, USA.
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Abstract
The knowledge on element 43 (Tc) of the periodic table, built over the years through the contributions given by the close relationship between chemistry and nuclear medicine, allowed the development of new and increasingly effective radiopharmaceuticals useful both as perfusion and target specific imaging agents for SPECT (single photon emission tomography). Among the manifold Tc-compounds, Tc(V) nitrido complexes played a relevant role in the search for new technetium-99m radiopharmaceuticals, providing efficient labeling procedures that can be conveniently exploited for the design and synthesis of agents, also incorporating small organic molecules or peptides having defined structural features. With this work, we present an overview of four decades of research on the chemistry and on the nuclear medicine applications of Tc(V) nitrido complexes.
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Fang W, Liu S. New 99mTc Radiotracers for Myocardial Perfusion Imaging by SPECT. Curr Radiopharm 2019; 12:171-186. [PMID: 30727939 DOI: 10.2174/1874471012666190206102214] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Revised: 01/04/2019] [Accepted: 01/08/2019] [Indexed: 02/04/2023]
Abstract
OBJECTIVE Myocardial Perfusion Imaging (MPI) with radiotracers is an integral component in evaluation of the patients with known or suspected coronary artery diseases (CAD). 99mTc-Sestamibi and 99mTc-Tetrofosmin are commercial radiopharmaceuticals for MPI by single photon-emission computed tomography (SPECT). Despite their widespread clinical applications, they do not meet the requirements of an ideal perfusion imaging agent due to their inability to linearly track the regional myocardial blood flow rate at >2.5 mL/min/g. With tremendous development of CZT-based SPECT cameras over the past several years, the nuclear cardiology community has been calling for better perfusion radiotracers with improved extraction and biodistribution properties. METHODS This review will summarize recent research efforts on new cationic and neutral 99mTc radiotracers for SPECT MPI. The goal of these efforts is to develop a 99mTc radiotracer that can be used to detect perfusion defects at rest or under stress, determine the regional myocardial blood flow, and measure the perfusion and left ventricular function. RESULTS The advantage of cationic radiotracers (e.g. 99mTc-Sestamibi) is their long myocardial retention because of the positive molecular charge and fast liver clearance kinetics. 99mTc-Teboroxime derivatives have a high initial heart uptake (high first-pass extraction fraction) due to their neutrality. 99mTc- 3SPboroxime is the most promising radiotracer for future clinical translation considering its initial heart uptake, myocardial retention time, liver clearance kinetics, heart/liver ratios and SPECT image quality. CONCLUSION 99mTc-3SPboroximine is an excellent example of perfusion radiotracers, the heart uptake of which is largely relies on the regional blood flow. It is possible to use 99mTc-3SPboroximine for detection of perfusion defect(s), accurate quantification and determination of regional blood flow rate. Development of such a 99mTc radiotracer is of great clinical benefit for accurate diagnosis of CAD and assessing the risk of future hard events (e.g. heart attack and sudden death) in cardiac patients.
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Affiliation(s)
- Wei Fang
- Department of Nuclear Medicine, Fuwai Hospital, the National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, No.167 North Lishi Road, Xicheng District, Beijing, China
| | - Shuang Liu
- School of Health Sciences, Purdue University, Beijing, IN 47907, United States
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Salvarese N, Carta D, Marzano C, Gerardi G, Melendez-Alafort L, Bolzati C. [99mTc][Tc(N)(DASD)(PNPn)]+ (DASD = 1,4-Dioxa-8-azaspiro[4,5]decandithiocarbamate, PNPn = Bisphosphinoamine) for Myocardial Imaging: Synthesis, Pharmacological and Pharmacokinetic Studies. J Med Chem 2018; 61:11114-11126. [DOI: 10.1021/acs.jmedchem.8b01191] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Affiliation(s)
- Nicola Salvarese
- Institute of Condensed Matter Chemistry and Technologies for Energy (ICMATE)-CNR, Corso Stati Uniti, 4, 35127 Padova, Italy
| | - Davide Carta
- Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Via Marzolo, 5, 35131 Padova, Italy
| | - Cristina Marzano
- Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Via Marzolo, 5, 35131 Padova, Italy
| | - Gabriele Gerardi
- Department of Veterinary Clinical Science, University of Padua, Viale dell’Università 16, 35020 Legnaro, Padua, Italy
| | | | - Cristina Bolzati
- Institute of Condensed Matter Chemistry and Technologies for Energy (ICMATE)-CNR, Corso Stati Uniti, 4, 35127 Padova, Italy
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Yang Y, Zheng Y, Tomaselli E, Fang W, Liu S. Impact of Boronate Capping Groups on Biological Characteristics of Novel99mTc(III) Complexes [99mTcCl(CDO)(CDOH)2B-R] (CDOH2= Cyclohexanedione Dioxime). Bioconjug Chem 2015; 26:316-28. [PMID: 25585053 DOI: 10.1021/bc500583k] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Yong Yang
- Department of Nuclear Medicine, Cardiovascular Institute & Fu Wai Hospital, Chinese Academy of Medical Science & Peking Union Medical College, Beijing 100037, China
- School of Health Sciences, Purdue University, West Lafayette, Indiana 47907, United States
| | - Yumin Zheng
- Department of Nuclear Medicine, China-Japan Friendship Hospital, Beijing 100029, China
| | - Elena Tomaselli
- School of Health Sciences, Purdue University, West Lafayette, Indiana 47907, United States
| | - Wei Fang
- Department of Nuclear Medicine, Cardiovascular Institute & Fu Wai Hospital, Chinese Academy of Medical Science & Peking Union Medical College, Beijing 100037, China
| | - Shuang Liu
- School of Health Sciences, Purdue University, West Lafayette, Indiana 47907, United States
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Zheng Y, Ji S, Tomaselli E, Liu S. Development of kit formulations for (99m) TcN-MPO: a cationic radiotracer for myocardial perfusion imaging. J Labelled Comp Radiopharm 2014; 57:584-92. [PMID: 25070025 DOI: 10.1002/jlcr.3221] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Revised: 06/30/2014] [Accepted: 07/03/2014] [Indexed: 11/11/2022]
Abstract
The objective of this study was to develop a kit formulation for [(99m) TcN(mpo)(PNP5)](+) (MPO = 2-mercaptopyridine oxide), ((99m) TcN-MPO) to support its clinical evaluations as a SPECT radiotracer. Radiolabeling studies were performed using three different formulations (two-vial formulation and single-vial formulations with/without SnCl2 ) to explore the factors influencing radiochemical purity (RCP) of (99m) TcN-MPO. We found that the most important factor affecting the RCP of (99m) TcN-MPO was the purity of PNP5. (99m) TcN-MPO was prepared >98% RCP (n = 20) using the two-vial formulation. For single-vial formulations with/without SnCl2 , β-cyclodextrin (β-CD) is particularly useful as a stabilizer for PNP5. The RCP of (99m) TcN-MPO was 95-98% using β-CD, but its RCP was only 90-93% with γ-cyclodextrin (γ-CD). It seems that PNP5 fits better into the inner cavity of β-CD, which forms more stable inclusion complex than γ-CD in the single-vial formulations. The results from biodistribution and imaging studies in Sprague-Dawley rats clearly demonstrated biological equivalence of three different formulations. Single photon-emission computed tomography data suggested that high quality images could be obtained at 0-30-min post-injection without significant interference from the liver radioactivity. Considering the ease for (99m) Tc-labeling and high RCP of (99m) TcN-MPO, the non-SnCl2 single-vial formulation is an attractive choice for future clinical studies.
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Affiliation(s)
- Yumin Zheng
- School of Health Sciences, Purdue University, West Lafayette, IN, 47907, USA; Department of Nuclear Medicine, China-Japan Friendship Hospital, Beijing, 100029, China
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Bowen JD, Huang Q, Ellin JR, Lee TC, Shrestha U, Gullberg GT, Seo Y. Design and performance evaluation of a 20-aperture multipinhole collimator for myocardial perfusion imaging applications. Phys Med Biol 2013; 58:7209-26. [PMID: 24061162 PMCID: PMC3855225 DOI: 10.1088/0031-9155/58/20/7209] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Single photon emission computed tomography (SPECT) myocardial perfusion imaging remains a critical tool in the diagnosis of coronary artery disease. However, after more than three decades of use, photon detection efficiency remains poor and unchanged. This is due to the continued reliance on parallel-hole collimators first introduced in 1964. These collimators possess poor geometric efficiency. Here we present the performance evaluation results of a newly designed multipinhole collimator with 20 pinhole apertures (PH20) for commercial SPECT systems. Computer simulations and numerical observer studies were used to assess the noise, bias and diagnostic imaging performance of a PH20 collimator in comparison with those of a low energy high resolution (LEHR) parallel-hole collimator. Ray-driven projector/backprojector pairs were used to model SPECT imaging acquisitions, including simulation of noiseless projection data and performing MLEM/OSEM image reconstructions. Poisson noise was added to noiseless projections for realistic projection data. Noise and bias performance were investigated for five mathematical cardiac and torso (MCAT) phantom anatomies imaged at two gantry orbit positions (19.5 and 25.0 cm). PH20 and LEHR images were reconstructed with 300 MLEM iterations and 30 OSEM iterations (ten subsets), respectively. Diagnostic imaging performance was assessed by a receiver operating characteristic (ROC) analysis performed on a single MCAT phantom; however, in this case PH20 images were reconstructed with 75 pixel-based OSEM iterations (four subsets). Four PH20 projection views from two positions of a dual-head camera acquisition and 60 LEHR projections were simulated for all studies. At uniformly-imposed resolution of 12.5 mm, significant improvements in SNR and diagnostic sensitivity (represented by the area under the ROC curve, or AUC) were realized when PH20 collimators are substituted for LEHR parallel-hole collimators. SNR improves by factors of 1.94-2.34 for the five patient anatomies and two orbital positions studied. For the ROC analysis the PH20 AUC is larger than the LEHR AUC with a p-value of 0.0067. Bias performance, however, decreases with the use of PH20 collimators. Systematic analyses showed PH20 collimators present improved diagnostic imaging performance over LEHR collimators, requiring only collimator exchange on existing SPECT cameras for their use.
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Affiliation(s)
- Jason D. Bowen
- Physics Research Laboratory, Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, USA
| | - Qiu Huang
- Shanghai Jiaotong University, Shanghai, China
| | - Justin R. Ellin
- Physics Research Laboratory, Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, USA
| | - Tzu-Cheng Lee
- Physics Research Laboratory, Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, USA
| | - Uttam Shrestha
- Physics Research Laboratory, Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, USA
| | - Grant T. Gullberg
- Physics Research Laboratory, Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, USA
- Department of Radiotracer Development and Imaging Technology, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Youngho Seo
- Physics Research Laboratory, Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, USA
- Department of Radiation Oncology, University of California, San Francisco, California, USA
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Ma H, Li S, Wu Z, Liu J, Liu H, Guo X. Comparison of ⁹⁹mTc-N-DBODC5 and ⁹⁹mTc-MIBI of myocardial perfusion imaging for diagnosis of coronary artery disease. BIOMED RESEARCH INTERNATIONAL 2013; 2013:145427. [PMID: 23841052 PMCID: PMC3693116 DOI: 10.1155/2013/145427] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/20/2013] [Accepted: 05/20/2013] [Indexed: 11/28/2022]
Abstract
Despite recent advances in therapeutic and diagnostic approaches, coronary artery disease (CAD) and its related cardiac disorders represent the most common cause of death in the United States. Nuclear myocardial perfusion imaging (MPI) technologies play a pivotal role in the diagnosis and treatment design for CAD. Recently, in order to develop improved MPI agents for diagnosis of CAD, (99m)Tc-[bis(dimethoxypropylphosphinoethyl)-ethoxyethyl-amine(PNP5)]-[bis(N-ethoxyethyl)dithiocarbamato(DBODC)]nitride(N-DBODC5)((99m)Tc-N-DBODC5) with a faster liver clearance than conventional single-photon emission computed tomography (SPECT) imaging agents (technetium 99m sestamibi ((99m)Tc-MIBI) or technetium 99m tetrofosmin) has been introduced. In preclinical and phase I studies, (99m)Tc-N-DBODC5 has shown characteristics of an essentially ideal MPI tracer. Importantly, however, there is no data to support the use of (99m)Tc-N-DBODC5 to evaluate myocardial ischemia in patients with suspected CAD. The present study was designed to assess the clinical value of this agent; the findings of stress and rest MPI after the administration of this agent were compared to those of stress and rest (99m)Tc-MIBI, as well as those of coronary angiography, with respect to the detection of CAD. Our findings indicated the usefulness of (99m)Tc-N-DBODC5 as a promising MPI agent.
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Affiliation(s)
- Haiyan Ma
- Department of Nuclear Medicine, First Affiliated Hospital of Shanxi Medical University, 85 Jiefang South Road, Taiyuan, Shanxi 030001, China
| | - Sijin Li
- Department of Nuclear Medicine, First Affiliated Hospital of Shanxi Medical University, 85 Jiefang South Road, Taiyuan, Shanxi 030001, China
| | - Zhifang Wu
- Department of Nuclear Medicine, First Affiliated Hospital of Shanxi Medical University, 85 Jiefang South Road, Taiyuan, Shanxi 030001, China
| | - Jianzhong Liu
- Department of Nuclear Medicine, First Affiliated Hospital of Shanxi Medical University, 85 Jiefang South Road, Taiyuan, Shanxi 030001, China
| | - Haiyan Liu
- Department of Nuclear Medicine, First Affiliated Hospital of Shanxi Medical University, 85 Jiefang South Road, Taiyuan, Shanxi 030001, China
| | - Xiaoshan Guo
- Department of Nuclear Medicine, First Affiliated Hospital of Shanxi Medical University, 85 Jiefang South Road, Taiyuan, Shanxi 030001, China
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(99m)Tc(N)-DBODC(5), a potential radiolabeled probe for SPECT of multidrug resistance: in vitro study. J Biol Inorg Chem 2013; 18:523-38. [PMID: 23543234 DOI: 10.1007/s00775-013-0997-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2012] [Accepted: 03/10/2013] [Indexed: 12/13/2022]
Abstract
[(99m)Tc(N)(DBODC)(PNP5)](+) [DBODC is bis(N-ethoxyethyl)dithiocarbamato; PNP5 is bis(dimethoxypropylphosphinoethyl)ethoxyethylamine], abbreviated as (99m)Tc(N)-DBODC(5), is a lipophilic cationic mixed compound investigated as a myocardial imaging agent. The findings that this tracer accumulates in mitochondrial structures through a mechanism mediated by the negative mitochondrial membrane potential and that the rapid efflux of (99m)Tc(N)-DBODC(5) from nontarget tissues seems to be associated with the multidrug resistance (MDR) P-glycoprotein (P-gp) transport function open up the possibility to extend its clinical applications to tumor imaging and noninvasive MDR studies. The rate of uptake at 4 and 37 °C of (99m)Tc(N)-DBODC(5) was evaluated in vitro in selected human cancer cell lines and in the corresponding sublines before and after P-gp and/or MDR-associated protein (MRP) modulator/inhibitor treatment using (99m)Tc-sestamibi as a reference. The results indicated that (1) the uptake of both (99m)Tc(N)-DBODC(5) and (99m)Tc-sestamibi is correlated to metabolic activity of the cells and (2) the cellular accumulation is connected to the level of P-gp/MRP expression; in fact, an enhancement of uptake in resistant cells was observed after treatment with opportune MDR inhibitor/modulator, indicating that the selective blockade of P-gp/MRP prevented efflux of the tracers. This study provides a preliminary indication of the applicability of (99m)Tc(N)-DBODC(5) in tumor imaging and in detecting P-gp/MRP-mediated drug resistance in human cancer. In addition, the possibility to control the hydrophobicity and pharmacological activity of this heterocomplex through the variation of the substituents on the ligands backbone without affecting the P2S2 coordinating sphere makes (99m)Tc(N)-DBODC(5) a suitable scaffold for the preparation of a molecular probe for single photon emission computed tomography of MDR.
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Zeng H, Zhao L, Hu S, Liu Y, Yu H, Chen N, Zhang H. Synthesis, characterization and biodistribution of new fatty acids conjugates bearing N,N,N-donors incorporated [99mTc/Re(CO)3]+. Dalton Trans 2013; 42:2894-901. [DOI: 10.1039/c2dt32492j] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Broisat A, Ruiz M, Goodman NC, Hanrahan SM, Reutter BW, Brennan KM, Janabi M, Schaefer S, Watson DD, Beller GA, VanBrocklin HF, Glover DK. Myocardial uptake of 7'-(Z)-[(123)I]iodorotenone during vasodilator stress in dogs with critical coronary stenoses. Circ Cardiovasc Imaging 2011; 4:685-92. [PMID: 21917783 DOI: 10.1161/circimaging.110.961763] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND There is a well-recognized need for a new generation of single photon emission computed tomography (SPECT) perfusion tracers with improved myocardial extraction over a wide flow range. Radiotracers that target complex I of the mitochondrial electron transport chain have been proposed as a new class of myocardial perfusion imaging agents. 7-(Z)-[(125)I]iodorotenone ((125)I-ZIROT) has demonstrated superior myocardial extraction and retention characteristics in rats and in isolated perfused rabbit hearts. We sought to fully characterize the biodistribution and myocardial extraction versus flow relationship of (123)I-ZIROT in an intact large-animal model. METHODS AND RESULTS The (123)I-ZIROT was administered during adenosine A(2A) agonist-induced hyperemia in 5 anesthetized dogs with critical left anterior descending (LAD) stenoses. When left circumflex (LCx) flow was maximal, (123)I-ZIROT and microspheres were coinjected and the dogs were euthanized 5 minutes later. (123)I-ZIROT biodistribution was evaluated in 2 additional dogs by in vivo planar imaging. At (123)I-ZIROT injection, transmural LAD flow was unchanged from baseline (mean±SEM, 0.90±0.22 versus 0.87±0.11 mL/[min · g]; P=0.92), whereas LCx zone flow increased significantly (mean±SEM, 3.25±0.51 versus 1.00±0.17 mL/[min · g]; P<0.05). Myocardial (123)I-ZIROT extraction tracked regional myocardial flow better than either thallium-201 or (99m)Tc-sestamibi from previous studies using a similar model. Furthermore, the (123)I-ZIROT LAD/LCx activity ratios by ex vivo imaging or well counting (mean±SEM, 0.42±0.08 and 0.45±0.1, respectively) only slightly underestimated the LAD/LCx microsphere flow ratio (0.32±0.09). CONCLUSIONS The ability of (123)I-ZIROT to more linearly track blood flow over a wide range makes it a promising new SPECT myocardial perfusion imaging agent with potential for improved coronary artery disease detection and better quantitative estimation of the severity of flow impairment.
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Affiliation(s)
- Alexis Broisat
- Experimental Cardiology Laboratory, Cardiovascular Division, Department of Medicine, University of Virginia Health System, Charlottesville, VA 22908, USA
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Evaluation of (99) (m)TcN-MPO as a new myocardial perfusion imaging agent in normal dogs and in an acute myocardial infarction canine model: comparison with (99) (m)Tc-sestamibi. Mol Imaging Biol 2011; 13:121-7. [PMID: 20458635 DOI: 10.1007/s11307-010-0304-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
PURPOSE (99) (m)TcN-MPO ([(99) (m)TcN(mpo)(PNP5)](+): mpo = 2-mercaptopyridine oxide and PNP5 = N-ethoxyethyl-N,N-bis[2-(bis(3-methoxypropyl)phosphino)ethyl]amine) is a cationic (99) (m)Tc-nitrido complex, which has favorable biodistribution and myocardial uptake with rapid liver clearance in Sprague Dawley rats. The objective of this study was to compare the biodistribution and pharmacokinetics of (99) (m)TcN-MPO and (99) (m)Tc-Sestamibi in normal dogs, and to evaluate the potential of (99) (m)TcN-MPO as a myocardial perfusion agent in canines with acute myocardial infarction. METHODS Five normal mongrel dogs were injected intravenously with (99) (m)TcN-MPO. Venous blood samples were collected via a femoral vein catheter at 0.5, 1, 2, 3, 4, 5, 10, 20, 30, 40, 60, and 90 min post-injection (p.i.). Anterior-posterior planar images were acquired by γ-camera at 10, 20, 30, 60, 90, and 120 min p.i. Regions of interest (ROIs) were drawn around the heart, liver, and lungs. The heart/liver and heart/lung ratios were calculated by dividing the mean counts in heart ROI by the mean counts in the liver and lung ROI, respectively. For comparison, (99) (m)Tc-sestamibi was also evaluated in the same five dogs. The interval period between the two examinations was 1 week to eliminate possible interference between these two radiotracers. In addition, single positron emission computed tomography (SPECT) images in the canine infarct model were collected 24 h after myocardial infarction at 30 and 60 min after the administration of (99) (m)TcN-MPO (n = 4) or (99) (m)Tc-Sestamibi (n = 4). RESULTS It was found that (99) (m)TcN-MPO and (99) (m)Tc-Sestamibi displayed very similar blood clearance characteristics during the first 90 min p.i. Both (99) (m)TcN-MPO and (99) (m)Tc-Sestamibi had a rapid blood clearance with less than 50% of initial radioactivity remaining at 1 min and less than 5% at 30 min p.i. (99) (m)TcN-MPO and (99) (m)Tc-Sestamibi both showed good heart/lung contrast. The heart/liver ratio of (99) (m)TcN-MPO increased with time (0.53 ± 0.06 at 10 min, 0.90 ± 0.062 at 30 min, and 1.22 ± 0.06 at 60 min p.i.), whereas the heart/liver ratio of (99) (m)Tc-Sestamibi remained low at all time points (0.50 ± 0.03 at 10 min, 0.64 ± 0.03 at 30 min, and 0.60 ± 0.02 at 60 min p.i.). SPECT imaging studies in canines with acute myocardial infarction indicated that good visualization of the left ventricular wall and perfusion defects could be achieved at 30 min after administration of (99) (m)TcN-MPO but not after (99) (m)Tc-Sestamibi. CONCLUSION The combination of reasonable heart uptake with rapid hepatobiliary excretion makes (99) (m)TcN-MPO a promising new radiotracer for myocardial perfusion imaging.
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Cuocolo A, Cittanti C, Acampa W, Larobina M, Petretta M. Current and Future Status of Blood Flow Tracers. CURRENT CARDIOVASCULAR IMAGING REPORTS 2011. [DOI: 10.1007/s12410-011-9081-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Riou LM, Broisat A. Novel SPECT perfusion imaging agents with improved myocardial or liver kinetics: experimental studies and the need for clinical evaluation. J Nucl Cardiol 2010; 17:771-4. [PMID: 20683788 DOI: 10.1007/s12350-010-9275-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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Liu Z, Chen L, Liu S, Barber C, Stevenson GD, Furenlid LR, Barrett HH, Woolfenden JM. Kinetic characterization of a novel cationic (99m)Tc(I)-tricarbonyl complex, (99m)Tc-15C5-PNP, for myocardial perfusion imaging. J Nucl Cardiol 2010; 17:858-67. [PMID: 20669059 PMCID: PMC2940957 DOI: 10.1007/s12350-010-9262-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2009] [Accepted: 05/20/2010] [Indexed: 10/19/2022]
Abstract
BACKGROUND Intense liver uptake of (99m)Tc-sestamibi (MIBI) often interferes with visualization of myocardial perfusion in the inferior wall of the left ventricle. To develop improved myocardial perfusion agents, crown ether-containing dithiocarbamates and bisphosphines have been introduced in recent years. This study was designed to investigate the myocardial imaging properties and in vivo kinetics of a cationic (99m)Tc(I)-tricarbonyl complex, (99m)Tc-15C5-PNP, in comparison with MIBI. METHODS Dynamic cardiac images were acquired for 60 minutes after intravenous tracer injection using a small-animal SPECT system in healthy control rats and rats with myocardial infarcts. Myocardial and liver time-activity curves were generated for radiopharmaceutical kinetic analysis. RESULTS Good visualization of the left ventricular wall and perfusion defects could be achieved 20 minutes after (99m)Tc-15C5-PNP administration. (99m)Tc-15C5-PNP images in all hearts with infarcts showed perfusion defects, which were comparable to MIBI images. The kinetic curves plotted from 1 to 60 minutes demonstrated that (99m)Tc-15C5-PNP has a shorter washout half-life (6.4 ± 3.2 vs 124 ± 30.5 minutes, P < .01) in the liver, lower residual liver activity (14.5 ± 10.2% vs 36.5 ± 28.9%, P < .01), and higher heart/liver ratio than MIBI. CONCLUSIONS (99m)Tc-15C5-PNP has potential for rapid myocardial perfusion imaging with low liver uptake.
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Affiliation(s)
- Zhonglin Liu
- Department of Radiology, University of Arizona, P.O. Box 245067, Tucson, AZ 85724-5067, USA.
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Bolzati C, Cavazza-Ceccato M, Agostini S, Refosco F, Yamamichi Y, Tokunaga S, Carta D, Salvarese N, Bernardini D, Bandoli G. Biological in Vitro and in Vivo Studies of a Series of New Asymmetrical Cationic [99mTc(N)(DTC-Ln)(PNP)]+ Complex (DTC-Ln = Alicyclic Dithiocarbamate and PNP = Diphosphinoamine). Bioconjug Chem 2010; 21:928-39. [DOI: 10.1021/bc900493e] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- Cristina Bolzati
- ICIS-CNR, Corso Stati Uniti, 4, 35127 Padova, Italy, Department of Pharmaceutical Sciences, University of Padua, Via Marzolo, 5, 35131 Padova, Italy, Research Center, Nihon Medi-Physics Co., Ltd., 3-1 Kitasode, Sodegaura, Chiba 299-0266, Japan, and Department of Veterinary Clinical Science, University of Padua, Viale dell’Università 16, 35020 Legnaro, Padua, Italy
| | - Mario Cavazza-Ceccato
- ICIS-CNR, Corso Stati Uniti, 4, 35127 Padova, Italy, Department of Pharmaceutical Sciences, University of Padua, Via Marzolo, 5, 35131 Padova, Italy, Research Center, Nihon Medi-Physics Co., Ltd., 3-1 Kitasode, Sodegaura, Chiba 299-0266, Japan, and Department of Veterinary Clinical Science, University of Padua, Viale dell’Università 16, 35020 Legnaro, Padua, Italy
| | - Stefania Agostini
- ICIS-CNR, Corso Stati Uniti, 4, 35127 Padova, Italy, Department of Pharmaceutical Sciences, University of Padua, Via Marzolo, 5, 35131 Padova, Italy, Research Center, Nihon Medi-Physics Co., Ltd., 3-1 Kitasode, Sodegaura, Chiba 299-0266, Japan, and Department of Veterinary Clinical Science, University of Padua, Viale dell’Università 16, 35020 Legnaro, Padua, Italy
| | - Fiorenzo Refosco
- ICIS-CNR, Corso Stati Uniti, 4, 35127 Padova, Italy, Department of Pharmaceutical Sciences, University of Padua, Via Marzolo, 5, 35131 Padova, Italy, Research Center, Nihon Medi-Physics Co., Ltd., 3-1 Kitasode, Sodegaura, Chiba 299-0266, Japan, and Department of Veterinary Clinical Science, University of Padua, Viale dell’Università 16, 35020 Legnaro, Padua, Italy
| | - Yoshihiro Yamamichi
- ICIS-CNR, Corso Stati Uniti, 4, 35127 Padova, Italy, Department of Pharmaceutical Sciences, University of Padua, Via Marzolo, 5, 35131 Padova, Italy, Research Center, Nihon Medi-Physics Co., Ltd., 3-1 Kitasode, Sodegaura, Chiba 299-0266, Japan, and Department of Veterinary Clinical Science, University of Padua, Viale dell’Università 16, 35020 Legnaro, Padua, Italy
| | - Shinji Tokunaga
- ICIS-CNR, Corso Stati Uniti, 4, 35127 Padova, Italy, Department of Pharmaceutical Sciences, University of Padua, Via Marzolo, 5, 35131 Padova, Italy, Research Center, Nihon Medi-Physics Co., Ltd., 3-1 Kitasode, Sodegaura, Chiba 299-0266, Japan, and Department of Veterinary Clinical Science, University of Padua, Viale dell’Università 16, 35020 Legnaro, Padua, Italy
| | - Davide Carta
- ICIS-CNR, Corso Stati Uniti, 4, 35127 Padova, Italy, Department of Pharmaceutical Sciences, University of Padua, Via Marzolo, 5, 35131 Padova, Italy, Research Center, Nihon Medi-Physics Co., Ltd., 3-1 Kitasode, Sodegaura, Chiba 299-0266, Japan, and Department of Veterinary Clinical Science, University of Padua, Viale dell’Università 16, 35020 Legnaro, Padua, Italy
| | - Nicola Salvarese
- ICIS-CNR, Corso Stati Uniti, 4, 35127 Padova, Italy, Department of Pharmaceutical Sciences, University of Padua, Via Marzolo, 5, 35131 Padova, Italy, Research Center, Nihon Medi-Physics Co., Ltd., 3-1 Kitasode, Sodegaura, Chiba 299-0266, Japan, and Department of Veterinary Clinical Science, University of Padua, Viale dell’Università 16, 35020 Legnaro, Padua, Italy
| | - Daniele Bernardini
- ICIS-CNR, Corso Stati Uniti, 4, 35127 Padova, Italy, Department of Pharmaceutical Sciences, University of Padua, Via Marzolo, 5, 35131 Padova, Italy, Research Center, Nihon Medi-Physics Co., Ltd., 3-1 Kitasode, Sodegaura, Chiba 299-0266, Japan, and Department of Veterinary Clinical Science, University of Padua, Viale dell’Università 16, 35020 Legnaro, Padua, Italy
| | - Giuliano Bandoli
- ICIS-CNR, Corso Stati Uniti, 4, 35127 Padova, Italy, Department of Pharmaceutical Sciences, University of Padua, Via Marzolo, 5, 35131 Padova, Italy, Research Center, Nihon Medi-Physics Co., Ltd., 3-1 Kitasode, Sodegaura, Chiba 299-0266, Japan, and Department of Veterinary Clinical Science, University of Padua, Viale dell’Università 16, 35020 Legnaro, Padua, Italy
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Kim YS, Wang F, Liu S. Minimizing liver uptake of cationic Tc radiotracers with ether and crown ether functional groups. World J Hepatol 2010; 2:21-31. [PMID: 21160953 PMCID: PMC2999265 DOI: 10.4254/wjh.v2.i1.21] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2009] [Revised: 01/11/2010] [Accepted: 01/18/2010] [Indexed: 02/06/2023] Open
Abstract
Ischemia-related diseases, particularly coronary artery disease (CAD), account for the majority of deaths worldwide. Myocardial ischemia is a serious condition and the delay in reperfusion of ischemic tissues can be life-threatening. This is particular true in the aged population. Rapid and accurate early detection of myocardial ischemia is highly desirable so that various therapeutic regiments can be given before irreversible myocardial damage occurs. Myocardial perfusion imaging with radiotracers is an integral component in evaluations of patients with known or suspected CAD. (99m)Tc-Sestamibi and (99m)Tc-Tetrofosmin are commercial radiopharmaceuticals currently available for myocardial perfusion imaging. Despite their widespread clinical applications, both (99m)Tc-Sestamibi and (99m)Tc-Tetrofosmin do not meet the requirements of an ideal perfusion imaging agent, largely due to their high liver uptake. The intense liver uptake makes it difficult to interpret the heart activity in the inferior and left ventricular wall. Photon scattering from the high liver radioactivity accumulation remains a significant challenge for diagnosis of heart diseases. This review will summarize the most recent research efforts to minimize the liver uptake of cationic (99m)Tc radiotracers by using ether and crown ether-containing chelators. Fast liver clearance will shorten the duration of imaging protocols (< 30 min post-injection), and allow for early acquisition of heart images with high quality. Improvement of heart/liver ratio may permit better detection of the presence and extent of coronary artery disease. Identification of such a new radiotracer that allows for the improved noninvasive assessment of myocardial perfusion would be of considerable benefit in treatment of patients with suspected CAD.
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Affiliation(s)
- Young-Seung Kim
- Young-Seung Kim, Shuang Liu, School of Health Sciences, Purdue University, 550 Stadium Mall Drive, West Lafayette, IN 47907, United States
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Bolzati C, Cavazza-Ceccato M, Agostini S, Tisato F, Bandoli G. Technetium and rhenium in five-coordinate symmetrical and dissymmetrical nitrido complexes with alkyl phosphino-thiol ligands. Synthesis and structural characterization. Inorg Chem 2009; 47:11972-83. [PMID: 19007158 DOI: 10.1021/ic801436d] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The reactivity of bulky alkylphosphino-thiol ligands (PSH) toward nitride-M(V, VI) (M = Tc/Re) precursors was investigated. Neutral five-coordinate monosubstituted complexes of the type [M(N)(PS)Cl(PPh(3))] (Tc1-4, Re1-2) were prepared in moderate to high yields. It was found that these [M(N)(PS)Cl(PPh(3))] species underwent ligand-exchange reactions under mild conditions when reacted with bidentate mononegative ligands having soft donor atoms such as dithiocarbamates (NaL(n)) to afford stable dissymmetrical mixed-substituted complexes of the type [M(N)(PS)(L(n))] (Tc5,8-10, Re5-9) containing two different bidentate chelating ligands bound to the [M[triple bond]N](2+) moiety. In these reactions, the dithiocarbamate replaced the two labile monodentate ligands (Cl and PPh(3)) leaving the [M(N)(PS)](+) building block intact. In the above reactions, technetium and rhenium were found to behave in a similar way. Instead, under more drastic conditions, reactions of PSH with [M(N)Cl(2)(PPh(3))(2)] gave a mixture of monosubstituted [M(N)(PS)Cl(PPh(3))] and bis-substituted species [M(N)(PS)(2)] (Tc11-14) in the case of technetium, whereas only monosubstituted [M(N)(PS)Cl(PPh(3))] complexes were recovered for rhenium. All isolated products were characterized by elemental analysis, IR and multinuclear ((1)H, (13)C, and (31)P) NMR spectroscopies, ESI MS spectrometry, and X-ray crystal structure determination of the representative monosubstituted [Tc(N)(PStbu)Cl(PPh(3))] (Tc4) and mixed-substituted [Re(N)(PScy)(L(3))] (Re7) and [Re(N)(PSiso)(L(4))] (Re9) complexes. The latter rhenium complexes represent the first example of a square-pyramidal nitrido Re species with the basal plane defined by a PS(3) donor set. Monosubstituted [M(N)(PS)Cl(PPh(3))] species bearing the substitution-inert [M(N)(PS)](+) moieties act as suitable building blocks proposed for the construction of new classes of dissymmetrical nitrido compounds with potential application in the development of essential and target specific (99m)Tc and (188)Re radiopharmaceuticals for imaging and therapy, respectively.
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Kim YS, Shi J, Zhai S, Hou G, Liu S. Mechanism for myocardial localization and rapid liver clearance of Tc-99m-N-MPO: a new perfusion radiotracer for heart imaging. J Nucl Cardiol 2009; 16:571-9. [PMID: 19288164 DOI: 10.1007/s12350-009-9068-y] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2008] [Revised: 01/14/2009] [Accepted: 01/25/2009] [Indexed: 10/21/2022]
Abstract
BACKGROUND [Tc-99m-N(mpo)(PNP5)](+) (Tc-99m-N-MPO: Hmpo = 2-mercaptopyridine N-oxide and PNP5 = N-ethoxyethyl-N,N-bis[2-(bis(3-methoxypropyl)phosphino)ethyl]amine) is a new Tc-99m radiotracer useful for myocardial perfusion imaging. The main objective of this study is to elucidate the mechanism for myocardial localization and fast liver clearance of Tc-99m-N-MPO in comparison with Tc-99m-sestamibi ([Tc-99m-(MIBI)(6)](+): MIBI = 2-methoxy-2-methylpropylisonitrile). METHODS AND RESULTS Subcellular distribution of Tc-99m-N-MPO and Tc-99m-sestamibi was examined in the excised Sprague-Dawley (SD) rat myocardium. Biodistribution and planar imaging studies were performed using SD rats in the absence/presence of Cyclosporin-A. Due to negative plasma and mitochondrial potentials, 84.5% +/- 3.2% of Tc-99m-N-MPO was found in the mitochondrial fraction as compared to 88.0% +/- 1.5% of Tc-99m-sestamibi. There was no significant difference in their mitochondrial accumulation. Tc-99m-N-MPO was also able to retain its chemical integrity in rat myocardium. Pre-treatment of SD rats with Cys-A result in significant increase in the kidney and liver uptake of Tc-99m-N-MPO. CONCLUSION Tc-99m-N-MPO and Tc-99m-sestamibi share almost identical subcellular distribution and localization mechanism. The MDR transport function of hepatocytes and renal cells is responsible for the fast clearance kinetics of Tc-99m-N-MPO from liver and kidneys, respectively. Tc-99m-N-MPO is a very promising myocardial perfusion radiotracer with favorable biodistribution properties and rapid liver clearance.
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Affiliation(s)
- Young-Seung Kim
- School of Health Sciences, Purdue University, West Lafayette, IN 47907, USA
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Dahlberg ST. Assessment of myocardial perfusion with Tc-99m: image is everything. J Nucl Cardiol 2009; 16:493-6. [PMID: 19408065 DOI: 10.1007/s12350-009-9082-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2009] [Accepted: 03/20/2009] [Indexed: 10/20/2022]
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Zhang WC, Fang W, Li B, Wang XB, He ZX. Experimental Study of [ 99mTc(PNP5) (DBODC)] + as a New Myocardial Perfusion Imaging Agent. Cardiology 2009; 112:89-97. [DOI: 10.1159/000141013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2007] [Accepted: 02/08/2008] [Indexed: 11/19/2022]
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Evaluation of 99mTcN-15C5 as a new myocardial perfusion imaging agent in normal dogs and canines with coronary stenosis. Nucl Med Commun 2008; 29:775-81. [PMID: 18677204 DOI: 10.1097/mnm.0b013e328302ca4a] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES This study was designed to evaluate the biodistribution and blood clearance characteristics of 99mTcN-15C5 and its potential as a myocardial perfusion radiotracer. METHODS Five normal mongrel dogs were injected with 99mTcN-15C5 intravenously. Blood samples were collected at 0.5, 1, 2, 3, 4, 5, 10, 15, and 30 min postinjection (p.i.). Anterior planar images were acquired at 5, 15, 30, 60, 90, and 120 min p.i. Regions of interest (ROIs) were drawn around heart, liver, and lungs. The raw activity in each ROI was expressed as counts/pixel/min. Heart/liver and heart/lung ratios were calculated by dividing the mean counts in heart ROI by the mean counts in liver and lung ROI, respectively. For comparison, 99mTc-sestamibi was also evaluated in the same five dogs. In dogs with coronary stenoses, single photon emission computed tomography images were acquired at 30, 60, and 120 min after administration of 99mTcN-15C5 with/without adenosine. RESULTS 99mTcN-15C5 and 99mTc-sestamibi had very similar blood clearance characteristics during the first 30 min p.i. The heart/liver ratio of 99mTcN-15C5 increased from 0.48+/-0.05 at 5 min p.i. to 1.85+/-0.11 at 120 min p.i., whereas the heart/liver ratio of 99mTc-sestamibi was improved only slightly from 0.45+/-0.04 at 5 min p.i. to 0.74+/-0.15 at 120 min p.i. SPECT imaging studies in canines with coronary stenoses indicated that good visualization of the perfusion defect could be achieved at 30 min after administration of 99mTcN-15C5 with the adenosine stress. CONCLUSION The combination of high heart uptake and rapid liver clearance makes 99mTcN-15C5 a promising new radiotracer for myocardial perfusion imaging.
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Bolzati C, Cavazza-Ceccato M, Agostini S, Tokunaga S, Casara D, Bandoli G. Subcellular distribution and metabolism studies of the potential myocardial imaging agent [99mTc(N)(DBODC)(PNP5)]+. J Nucl Med 2008; 49:1336-44. [PMID: 18632814 DOI: 10.2967/jnumed.108.051482] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
UNLABELLED 99mTc(N)-DBODC5 is the lead compound of a new series of monocationic 99mTc(N)-based potential myocardial imaging agents that exhibit original biodistribution properties. This study was addressed to elucidate the mechanisms of distribution, retention, and elimination of this promising 99mTc(N)-agent. METHODS The sex-related in vitro and in vivo stability and the subcellular distribution of 99mTc(N)-DBODC5 were investigated. Studies were performed by considering binding to the serum proteins; stability in rat serum, human serum, and rat liver homogenates; and the chemical integrity of the complex after extraction from rat tissues such as heart, liver, and kidney, as well as from intestinal fluids and urine. The effect of cyclosporin A on the in vivo pharmacokinetic properties of 99mTc(N)-DBODC5 was also evaluated. Subcellular distribution of 99mTc(N)-DBODC5 in ex vivo rat heart was determined by standard differential centrifugation techniques. RESULTS No significant in vitro serum protein binding and no notable biotransformation of the native compound into different species by the in vitro action of the serum and liver enzymes was evidenced. In vivo experiments showed that sex affects the pharmacokinetic profile of the 99mTc(N)-complexes including metabolism and excretion. Chromatographic profiles of 99mTc(N)-radioactivity extracted from tissues and fluids of female rats were always coincident with the control. Conversely, a small percentage of metabolized species was detected by high-performance liquid chromatography in liver extracts of male rats. Furthermore, administration of cyclosporin A caused a significant reduction of lung, liver, and kidney washout along with a considerable variation in activity distribution in the intestinal tract in both male and female rats, thus indicating a possible implication of Pgp transporters in determining the biologic behavior of 99mTc(N)-DBODC5. However, this phenomenon was more pronounced in females. Subcellular distribution studies showed that 86.3% +/- 7.4% of 99mTc(N)-DBODC5 was localized into mitochondrial fraction as a result of the interaction with the negative membrane potential. CONCLUSION Evidence showing that the new 99mTc(N)-myocardial tracers behave as multidrug resistance-associated protein P-glycoprotein substrates, combined with their selective mitochondrial accumulation, strongly supports the possibility that diagnostic application of 99mTc(N)-DBODC5 can be extended to tumor imaging and noninvasive multidrug resistance studies.
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Cittanti C, Uccelli L, Pasquali M, Boschi A, Flammia C, Bagatin E, Casali M, Stabin MG, Feggi L, Giganti M, Duatti A. Whole-body biodistribution and radiation dosimetry of the new cardiac tracer 99mTc-N-DBODC. J Nucl Med 2008; 49:1299-304. [PMID: 18632816 DOI: 10.2967/jnumed.108.053132] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
UNLABELLED Our purpose was to evaluate the safety profile and biodistribution behavior in healthy human volunteers of the new myocardial perfusion tracer bis[(dimethoxypropylphosphanyl)ethyl]ethoxyethylamine N,N'-bis(ethoxyethyl)dithiocarbamato nitrido technetium(V) (99mTc-N-DBODC). METHODS Ten healthy male volunteers were injected with 99mTc-N-DBODC under both stress and rest conditions. Anterior and posterior planar gamma-camera images were collected at 5, 30, 60, 240, and 1,440 min after injection, with organ uptake quantified by region-of-interest analysis. Tracer kinetics in body fluids were determined by collecting blood and urine samples at different time points. RESULTS After injection, 99mTc-N-DBODC showed significant accumulation in the myocardium and prolonged retention. Under rest conditions, uptake in the heart, lungs, and liver at 5 min after injection was 1.67% +/- 0.13%, 1.16% +/- 0.07%, and 10.85% +/- 1.72%, respectively, of administered activity. Under stress conditions, heart uptake was significantly higher (2.07% +/- 0.22%). Radioactivity in the liver decreased to 3.64% +/- 0.98% and 2.37% +/- 0.48% at 60 and 240 min, respectively, after injection. This rapid liver clearance led to favorable heart-to-liver ratios, reaching values of 0.74 +/- 0.13 at rest and 1.26 +/- 0.28 during exercise 60 min after tracer administration. Radiation dose estimates were comparable to those obtained with other myocardial perfusion cationic compounds. CONCLUSION The high uptake in the myocardium and the fast liver washout of 99mTc-N-DBODC will allow SPECT images of the left ventricle to be acquired early and with excellent quality.
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Affiliation(s)
- Corrado Cittanti
- Laboratory of Nuclear Medicine and Nuclear Medicine Section, Department of Radiological Sciences, University of Ferrara, Ferrara, Italy
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Tc-99m-N-MPO: novel cationic Tc-99m radiotracer for myocardial perfusion imaging. J Nucl Cardiol 2008; 15:535-46. [PMID: 18674722 DOI: 10.1016/j.nuclcard.2008.02.022] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2007] [Accepted: 02/21/2008] [Indexed: 11/21/2022]
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-99m-sestamibi 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-99m-sestamibi (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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Cazzola E, Benini E, Pasquali M, Mirtschink P, Walther M, Pietzsch HJ, Uccelli L, Boschi A, Bolzati C, Duatti A. Labeling of Fatty Acid Ligands with the Strong Electrophilic Metal Fragment [99mTc(N)(PNP)]2+ (PNP = Diphosphane Ligand). Bioconjug Chem 2008; 19:450-60. [DOI: 10.1021/bc7002378] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Emiliano Cazzola
- Laboratory of Nuclear Medicine, Department of Radiological Sciences, University of Ferrara, 44100 Ferrara, Italy, Institute of Physiology, Medical Faculty Carl Gustav Carus, Technical University Dresden, 01307 Dresden, Germany, Institute of Radiopharmacy, Forschungszentrum Dresden-Rossendorf, PF 510119, 01314 Dresden, Germany, and ICIS-CNR, Corso Stati Uniti, 4, 35127 Padova, Italy
| | - Elisa Benini
- Laboratory of Nuclear Medicine, Department of Radiological Sciences, University of Ferrara, 44100 Ferrara, Italy, Institute of Physiology, Medical Faculty Carl Gustav Carus, Technical University Dresden, 01307 Dresden, Germany, Institute of Radiopharmacy, Forschungszentrum Dresden-Rossendorf, PF 510119, 01314 Dresden, Germany, and ICIS-CNR, Corso Stati Uniti, 4, 35127 Padova, Italy
| | - Micol Pasquali
- Laboratory of Nuclear Medicine, Department of Radiological Sciences, University of Ferrara, 44100 Ferrara, Italy, Institute of Physiology, Medical Faculty Carl Gustav Carus, Technical University Dresden, 01307 Dresden, Germany, Institute of Radiopharmacy, Forschungszentrum Dresden-Rossendorf, PF 510119, 01314 Dresden, Germany, and ICIS-CNR, Corso Stati Uniti, 4, 35127 Padova, Italy
| | - Peter Mirtschink
- Laboratory of Nuclear Medicine, Department of Radiological Sciences, University of Ferrara, 44100 Ferrara, Italy, Institute of Physiology, Medical Faculty Carl Gustav Carus, Technical University Dresden, 01307 Dresden, Germany, Institute of Radiopharmacy, Forschungszentrum Dresden-Rossendorf, PF 510119, 01314 Dresden, Germany, and ICIS-CNR, Corso Stati Uniti, 4, 35127 Padova, Italy
| | - Martin Walther
- Laboratory of Nuclear Medicine, Department of Radiological Sciences, University of Ferrara, 44100 Ferrara, Italy, Institute of Physiology, Medical Faculty Carl Gustav Carus, Technical University Dresden, 01307 Dresden, Germany, Institute of Radiopharmacy, Forschungszentrum Dresden-Rossendorf, PF 510119, 01314 Dresden, Germany, and ICIS-CNR, Corso Stati Uniti, 4, 35127 Padova, Italy
| | - Hans-Jurgen Pietzsch
- Laboratory of Nuclear Medicine, Department of Radiological Sciences, University of Ferrara, 44100 Ferrara, Italy, Institute of Physiology, Medical Faculty Carl Gustav Carus, Technical University Dresden, 01307 Dresden, Germany, Institute of Radiopharmacy, Forschungszentrum Dresden-Rossendorf, PF 510119, 01314 Dresden, Germany, and ICIS-CNR, Corso Stati Uniti, 4, 35127 Padova, Italy
| | - Licia Uccelli
- Laboratory of Nuclear Medicine, Department of Radiological Sciences, University of Ferrara, 44100 Ferrara, Italy, Institute of Physiology, Medical Faculty Carl Gustav Carus, Technical University Dresden, 01307 Dresden, Germany, Institute of Radiopharmacy, Forschungszentrum Dresden-Rossendorf, PF 510119, 01314 Dresden, Germany, and ICIS-CNR, Corso Stati Uniti, 4, 35127 Padova, Italy
| | - Alessandra Boschi
- Laboratory of Nuclear Medicine, Department of Radiological Sciences, University of Ferrara, 44100 Ferrara, Italy, Institute of Physiology, Medical Faculty Carl Gustav Carus, Technical University Dresden, 01307 Dresden, Germany, Institute of Radiopharmacy, Forschungszentrum Dresden-Rossendorf, PF 510119, 01314 Dresden, Germany, and ICIS-CNR, Corso Stati Uniti, 4, 35127 Padova, Italy
| | - Cristina Bolzati
- Laboratory of Nuclear Medicine, Department of Radiological Sciences, University of Ferrara, 44100 Ferrara, Italy, Institute of Physiology, Medical Faculty Carl Gustav Carus, Technical University Dresden, 01307 Dresden, Germany, Institute of Radiopharmacy, Forschungszentrum Dresden-Rossendorf, PF 510119, 01314 Dresden, Germany, and ICIS-CNR, Corso Stati Uniti, 4, 35127 Padova, Italy
| | - Adriano Duatti
- Laboratory of Nuclear Medicine, Department of Radiological Sciences, University of Ferrara, 44100 Ferrara, Italy, Institute of Physiology, Medical Faculty Carl Gustav Carus, Technical University Dresden, 01307 Dresden, Germany, Institute of Radiopharmacy, Forschungszentrum Dresden-Rossendorf, PF 510119, 01314 Dresden, Germany, and ICIS-CNR, Corso Stati Uniti, 4, 35127 Padova, Italy
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Liu S. Ether and crown ether-containing cationic 99mTc complexes useful as radiopharmaceuticals for heart imaging. Dalton Trans 2007:1183-93. [PMID: 17353949 DOI: 10.1039/b618406e] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
While radiopharmaceutical research has been focused on the development of target-specific radiotracers for early detection and radiotherapy of cancers in the last decade, there is a limited effort on new cationic 99mTc radiotracers for heart imaging. This review will summarize some of the most recent developments in ether- and crown ether-containing cationic 99mTc radiotracers that have a fast liver clearance with a heart/liver ratio substantially better than that of 99mTc-Sestamibi and 99mTc-Tetrofosmin, the two commercial 99mTc radiopharmaceuticals currently available for myocardial perfusion imaging. Fast liver clearance might shorten the duration of imaging protocols (<30 min post-injection), and allow for early acquisition of heart images of high quality. Improvement of heart/liver ratio may permit better detection of the presence and extent of coronary artery disease. Identification of such a new radiotracer that allows for the improved non-invasive delineation of myocardial perfusion would be of considerable benefit in treatment of patients with suspected coronary artery disease.
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Affiliation(s)
- Shuang Liu
- School of Health Sciences, Purdue University, 550 Stadium Mall Drive, West Lafayette, IN 47907, USA.
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