1
|
Sidorenko GV, Miroslavov AE, Tyupina MY. Technetium(I) carbonyl complexes for nuclear medicine: Coordination-chemical aspect. Coord Chem Rev 2023. [DOI: 10.1016/j.ccr.2022.214911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|
2
|
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.
Collapse
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;
| |
Collapse
|
3
|
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.
Collapse
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.
| |
Collapse
|
4
|
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.
Collapse
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
| |
Collapse
|
5
|
Abstract
The present study aimed to discuss the role of mitochondrion in cardiac function and disease. The mitochondrion plays a fundamental role in cellular processes ranging from metabolism to apoptosis. The mitochondrial-targeted molecular imaging could potentially illustrate changes in global and regional cardiac dysfunction. The collective changes that occur in mitochondrial-targeted molecular imaging probes have been widely explored and developed. As probes currently used in the preclinical setting still have a lot of shortcomings, the development of myocardial metabolic activity, viability, perfusion, and blood flow molecular imaging probes holds great potential for accurately evaluating the myocardial viability and functional reserve. The advantages of molecular imaging provide a perspective on investigating the mitochondrial function of the myocardium in vivo noninvasively and quantitatively. The molecular imaging tracers of single-photon emission computed tomography and positron emission tomography could give more detailed information on myocardial metabolism and restoration. In this study, series mitochondrial-targeted 99mTc-, 123I-, and 18F-labeled tracers displayed broad applications because they could provide a direct link between mitochondrial dysfunction and cardiac disease.
Collapse
|
6
|
Liu M, Zheng Y, Avcibasi U, Liu S. Novel 99mTc(III)-azide complexes [ 99mTc(N 3)(CDO)(CDOH) 2B-R] (CDOH 2=cyclohexanedione dioxime) as potential radiotracers for heart imaging. Nucl Med Biol 2016; 43:732-741. [PMID: 27632344 DOI: 10.1016/j.nucmedbio.2016.05.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Accepted: 05/02/2016] [Indexed: 10/21/2022]
Abstract
INTRODUCTION In this study, novel 99mTc(III)-azide complexes [99mTc(N3)(CDO)(CDOH)2B-R] (99mTc-ISboroxime-N3: R=IS; 99mTc-MPboroxime-N3: R=MP; 99mTc-PAboroxime-N3: R=PA; 99mTc-PYboroxime-N3: R=PY; and 99mTc-Uboroxime-N3: R=5U) were evaluated as heart imaging agents. METHODS Complexes [99mTc(N3)(CDO)(CDOH)2B-R] (R=IS, MP, PA, PY and 5U) were prepared by ligand exchange between NaN3 and [99mTcCl(CDO)(CDOH)2B-R]. Biodistribution and imaging studies were carried out in Sprague-Dawley rats. Image quantification was performed to compare their initial heart uptake and myocardial retention. RESULTS 99mTc-ISboroxime-N3, 99mTc-PYboroxime-N3 and 99mTc-Uboroxime-N3 were prepared with high RCP (93-98%) while the RCP of 99mTc-MPboroxime-N3 and 99mTc-PAboroxime-N3 was 80-85%. The myocardial retention curves of 99mTc-ISboroxime-N3, 99mTc-PYboroxime-N3 and 99mTc-Uboroxime-N3 were best fitted to the bi-exponential decay function. The half-time of the fast component was 1.6±0.4min for 99mTc-ISboroxime-N3, 0.7±0.1min for 99mTc-PYboroxime-N3 and 0.9±0.4min for 99mTc-Uboroxime-N3. The 2-min heart uptake from biodistribution studies followed the ranking order of 99mTc-ISboroxime-N3 (3.60±0.68%ID/g)>99mTc-PYboroxime-N3 (2.35±0.37%ID/g)≫99mTc-Uboroxime-N3 (1.29±0.06%ID/g). 99mTc-ISboroxime-N3 had the highest 2-min heart uptake among 99mTc radiotracers revaluated in SD rats. High quality SPECT images were obtained with the right and left ventricular walls being clearly delineated. The best image acquisition window was 0-5min for 99mTc-ISboroxime-N3. CONCLUSION Both azide coligand and boronate caps had significant impact on the heart uptake and myocardial retention of complexes [99mTc(N3)(CDO)(CDOH)2B-R]. Among the radiotracers evaluated in SD rats, 99mTc-ISboroxime-N3 has the highest initial heart uptake with the heart retention comparable to that of 99mTc-Teboroxime. 99mTc-ISboroxime-N3 is a promising alternative to 99mTc-Teboroxime for SPECT MPI.
Collapse
Affiliation(s)
- Min Liu
- Department of Radiation Medicine and Protection, Medical College, Soochow University, China; School of Health Sciences, Purdue University, IN, 47907, USA
| | - Yumin Zheng
- Department of Nuclear Medicine, China-Japan Friendship Hospital, Beijing, 100037, China
| | - Ugur Avcibasi
- School of Health Sciences, Purdue University, IN, 47907, USA; Department of Chemistry, Faculty of Arts and Science, Celal Bayar University, 45040, Yunusemre/Manisa, Turkey
| | - Shuang Liu
- School of Health Sciences, Purdue University, IN, 47907, USA.
| |
Collapse
|
7
|
Alexanderson-Rosas E, Guinto-Nishimura GY, Cruz-Mendoza JR, Oropeza-Aguilar M, De La Fuente-Mancera JC, Barrero-Mier AF, Monroy-Gonzalez A, Juarez-Orozco LE, Cano-Zarate R, Meave-Gonzalez A. Current and future trends in multimodality imaging of coronary artery disease. Expert Rev Cardiovasc Ther 2015; 13:715-31. [PMID: 25912725 DOI: 10.1586/14779072.2015.1039991] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Nowadays, there is a wide array of imaging studies available for the evaluation of coronary artery disease, each with its particular indications and strengths. Cardiac single photon emission tomography is mostly used to evaluate myocardial perfusion, having experienced recent marked improvements in image acquisition. Cardiac PET has its main utility in perfusion imaging, atherosclerosis and endothelial function evaluation, and viability assessment. Cardiovascular computed tomography has long been used as a reference test for non-invasive evaluation of coronary lesions and anatomic characterization. Cardiovascular magnetic resonance is currently the reference standard for non-invasive ventricular function evaluation and myocardial scarring delineation. These specific strengths have been enhanced with the advent of hybrid equipment, offering a true integration of different imaging modalities into a single, simultaneous and comprehensive study.
Collapse
Affiliation(s)
- Erick Alexanderson-Rosas
- Department of Nuclear Cardiology, Instituto Nacional de Cardiología 'Ignacio Chávez', Mexico City, Mexico
| | | | | | | | | | | | | | | | | | | |
Collapse
|
8
|
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
| |
Collapse
|
9
|
Fernandes C, Maria L, Gano L, Santos IC, Santos I, Paulo A. Re(I) and 99mTc(I) tricarbonyl complexes with ether-containing pyrazolyl-based chelators: Chemistry, biodistribution and metabolism. J Organomet Chem 2014. [DOI: 10.1016/j.jorganchem.2013.11.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
|
10
|
New SPECT and PET radiopharmaceuticals for imaging cardiovascular disease. BIOMED RESEARCH INTERNATIONAL 2014; 2014:942960. [PMID: 24901002 PMCID: PMC4034657 DOI: 10.1155/2014/942960] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Accepted: 03/16/2014] [Indexed: 01/08/2023]
Abstract
Nuclear cardiology has experienced exponential growth within the past four decades with converging capacity to diagnose and influence management of a variety of cardiovascular diseases. Single photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) with technetium-99m radiotracers or thallium-201 has dominated the field; however new hardware and software designs that optimize image quality with reduced radiation exposure are fuelling a resurgence of interest at the preclinical and clinical levels to expand beyond MPI. Other imaging modalities including positron emission tomography (PET) and magnetic resonance imaging (MRI) continue to emerge as powerful players with an expanded capacity to diagnose a variety of cardiac conditions. At the forefront of this resurgence is the development of novel target vectors based on an enhanced understanding of the underlying pathophysiological process in the subcellular domain. Molecular imaging with novel radiopharmaceuticals engineered to target a specific subcellular process has the capacity to improve diagnostic accuracy and deliver enhanced prognostic information to alter management. This paper, while not comprehensive, will review the recent advancements in radiotracer development for SPECT and PET MPI, autonomic dysfunction, apoptosis, atherosclerotic plaques, metabolism, and viability. The relevant radiochemistry and preclinical and clinical development in addition to molecular imaging with emerging modalities such as cardiac MRI and PET-MR will be discussed.
Collapse
|
11
|
Gao S, Zhao G, Wen Q, Bai L, Chen B, Ji T, Ji B, Ma Q. Pharmacokinetics and biodistribution of 99mTc N-MPO in healthy human volunteers. Clin Nucl Med 2013; 39:e14-9. [PMID: 23917788 DOI: 10.1097/rlu.0b013e3182872a8c] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE Tc N-MPO ([Tc N(MPO)(PNP5)]: HMPO = 2-mercaptopyridine N-oxide, and PNP5 = N-ethoxyethyl-N,N-bis[2-(bis(3-methoxypropyl)phosphino)ethyl]amine) is a new Tc radiotracer useful for myocardial perfusion imaging. This study was designed to determine its pharmacokinetics and biodistribution in healthy volunteers. PATIENTS AND METHODS Ten healthy volunteers were involved in this study. Each subject was administered approximately 925 MBq of Tc N-MPO under rest or stress conditions (n = 5 per group). Whole-body planar images were obtained at 10, 30, 60, 240, and 1440 minutes after injection. Organ uptake was quantified by region-of-interest analysis. The blood clearance and urine excretion kinetics were determined by collecting blood and urine samples at different time points. RESULTS Tc N-MPO showed significant accumulation in myocardium with prolonged retention. At rest, its percentage of injected dose (%ID) uptake in the heart, lungs, and liver at 10 minutes after injection was 2.47% (0.64%), 1.84% (0.64%), and 20.88% (5.23%), respectively. The liver uptake decreased to 6.79%ID (1.60%ID) at 60 minutes after injection and 4.50%ID (1.86%ID) at 240 minutes after injection. Under stress conditions, the heart uptake was slightly increased (2.57%ID [0.21%ID]). The rapid liver clearance led to favorable heart-to-liver ratios, reaching values of 0.27%ID (0.07%ID) under rest condition and 0.28%ID (0.05%ID) under stress condition at 60 minutes after injection. CONCLUSIONS Tc N-MPO demonstrates a highly favorable biodistribution in humans. The high heart uptake and the fast liver washout of Tc N-MPO will allow SPECT images of the left ventricle to be acquired as early as 10 minutes after injection.
Collapse
Affiliation(s)
- Shi Gao
- From the Department of Nuclear Medicine, China-Japan Union Hospital, Jilin University, Changchun, China
| | | | | | | | | | | | | | | |
Collapse
|
12
|
(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.
Collapse
|
13
|
Abstract
Technetium and Rhenium are the two lower elements in the manganese triad. Whereas rhenium is known as an important part of high resistance alloys, technetium is mostly known as a cumbersome product of nuclear fission. It is less known that its metastable isotope 99mTc is of utmost importance in nuclear medicine diagnosis. The technical application of elemental rhenium is currently complemented by investigations of its isotope 188Re , which could play a central role in the future for internal, targeted radiotherapy. This article will briefly describe the basic principles behind diagnostic methods with radionuclides for molecular imaging, review the 99mTc -based radiopharmaceuticals currently in clinical routine and focus on the chemical challenges and current developments towards improved, radiolabeled compounds for diagnosis and therapy in nuclear medicine.
Collapse
Affiliation(s)
- ROGER ALBERTO
- University of Zürich, Institute of Inorganic Chemistry, Winterthurerstr. 190, CH-8057 Zürich, Switzerland
| |
Collapse
|
14
|
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.
Collapse
|
15
|
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]
|
16
|
Mendes F, Paulo A, Santos I. Metalloprobes for functional monitoring of tumour multidrug resistance by nuclear imaging. Dalton Trans 2011; 40:5377-93. [DOI: 10.1039/c0dt01275k] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
17
|
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]
|
18
|
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.
Collapse
Affiliation(s)
- Zhonglin Liu
- Department of Radiology, University of Arizona, P.O. Box 245067, Tucson, AZ 85724-5067, USA.
| | | | | | | | | | | | | | | |
Collapse
|
19
|
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
| |
Collapse
|
20
|
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.
Collapse
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
| | | | | |
Collapse
|
21
|
|
22
|
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.
Collapse
Affiliation(s)
- Young-Seung Kim
- School of Health Sciences, Purdue University, West Lafayette, IN 47907, USA
| | | | | | | | | |
Collapse
|
23
|
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]
|
24
|
Maria L, Fernandes C, Garcia R, Gano L, Paulo A, Santos IC, Santos I. Tris(pyrazolyl)methane99mTc tricarbonyl complexes for myocardial imaging. Dalton Trans 2009:603-6. [DOI: 10.1039/b817451b] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
25
|
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.
Collapse
|
26
|
|
27
|
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.
Collapse
|
28
|
Maria L, Cunha S, Videira M, Gano L, Paulo A, Santos IC, Santos I. Rhenium and technetium tricarbonyl complexes anchored by pyrazole-based tripods: novel lead structures for the design of myocardial imaging agents. Dalton Trans 2007:3010-9. [PMID: 17622418 DOI: 10.1039/b705226j] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This report describes the synthesis and biological evaluation of cationic (99m)Tc-tricarbonyl complexes anchored by ether-containing tris(pyrazolyl)methane or bis(pyrazolyl)ethanamine ligands to be applied in the design of radiopharmaceuticals for myocardial imaging: fac-[(99m)Tc(CO)(3){RC(pz)(3)}](+) (R = H (1a), MeOCH(2) (2a), EtOCH(2) (3a), (n)PrOCH(2) (4a)) and fac-[(99m)Tc(CO)(3){RNHCH(2)CH(pz)(2)}](+) (R = H (5a), MeO(CH(2))(2) (6a)) (pz = pyrazolyl). At the no carrier added level, complexes 1a-6a were obtained in high radiochemical yield (> 98%) by reaction of fac-[(99m)Tc(CO)(3)(H(2)O)(3)](+) with the corresponding tripod chelator in aqueous medium. All these complexes display a high in vitro and in vivo stability, except 6a which metabolizes in vivo yielding fac-[(99m)Tc(CO)(3){HO(CH(2))(2)NHCH(2)CH(pz)(2)}](+) (7a). Biological studies in mice have shown that among the radiotracers evaluated in this work, 3a, anchored by a tris(pyrazolyl)methane chelator bearing an ethyl methyl ether substituent, has the highest heart uptake (3.6 +/- 0.5%ID g(-1) at 60 min p.i.). Complex 3a presents also the best heart: blood, heart: liver and heart: lung ratios, appearing as the most promising as a potential myocardial imaging agent. The chemical identity of 1a-7a was ascertained by HPLC comparison with the previously reported fac-[Re(CO)(3){HC(pz)(3)}]Br (1) and with the novel fac-[Re(CO)(3){RC(pz)(3)}]Br (R = MeOCH(2) (2), EtOCH(2) (3), (n)PrOCH(2)(4)) and fac-[Re(CO)(3){RNHCH(2)CH(pz)(2)}]Br (R = H (5), MeO(CH(2))(2) (6) HO(CH(2))(2) (7)). The novel Re(I) tricarbonyl complexes, 2-7, were characterized by the common analytical techniques, including single crystal X-ray diffraction analysis. The solid state structure confirmed the presence of facial and tridentate (kappa(3)-N(3)) anchor ligands. Solution NMR studies have also shown that this kappa(3)-N(3) coordination mode is retained in solution for all complexes (2-7).
Collapse
Affiliation(s)
- Leonor Maria
- Departamento de Química, ITN, Estrada Nacional 10, 2686-953, Sacavém, Codex, Portugal
| | | | | | | | | | | | | |
Collapse
|
29
|
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.
Collapse
Affiliation(s)
- Shuang Liu
- School of Health Sciences, Purdue University, 550 Stadium Mall Drive, West Lafayette, IN 47907, USA.
| |
Collapse
|