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Mc Veigh M, Bellan LM. Microfluidic synthesis of radiotracers: recent developments and commercialization prospects. LAB ON A CHIP 2024; 24:1226-1243. [PMID: 38165824 DOI: 10.1039/d3lc00779k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2024]
Abstract
Positron emission tomography (PET) is a powerful diagnostic tool that holds incredible potential for clinicians to track a wide variety of biological processes using specialized radiotracers. Currently, however, a single radiotracer accounts for over 95% of procedures, largely due to the cost of radiotracer synthesis. Microfluidic platforms provide a solution to this problem by enabling a dose-on-demand pipeline in which a single benchtop platform would synthesize a wide array of radiotracers. In this review, we will explore the field of microfluidic production of radiotracers from early research to current development. Furthermore, the benefits and drawbacks of different microfluidic reactor designs will be analyzed. Lastly, we will discuss the various engineering considerations that must be addressed to create a fully developed, commercially effective platform that can usher the field from research and development to commercialization.
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Affiliation(s)
- Mark Mc Veigh
- Interdisciplinary Materials Science Program, Vanderbilt University, Nashville, TN, 37235, USA
| | - Leon M Bellan
- Department of Mechanical Engineering, Vanderbilt University, Nashville, TN, 37235, USA.
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN 37235, USA
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2
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Lu Y, He Y, Schibli R, Mu L, van Dam RM. Proof-of-concept optimization of a copper-mediated 18F-radiosynthesis of a novel MAGL PET tracer on a high-throughput microdroplet platform and its macroscale translation. LAB ON A CHIP 2023; 23:4652-4663. [PMID: 37818614 PMCID: PMC10608794 DOI: 10.1039/d3lc00735a] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/12/2023]
Abstract
Copper-mediated radiofluorination has demonstrated remarkable potential in forming aromatic C-18F bonds of radioligands for positron emission tomography (PET). Achieving optimal results often requires optimization efforts, requiring a substantial amount of radiolabeling precursor and time, severely limiting the experimental throughput. Recently, we successfully showcased the feasibility of performing and optimizing Cu-mediated radiosynthesis on a high-throughput microdroplet platform using the well-known and clinically used radioligand [18F]FDOPA as an illustrative example. In our current work, we optimized the Cu-mediated synthesis of a novel monoacylglycerol lipase (MAGL) PET tracer ([18F]YH149), showing the versatility of droplet-based techniques for early stage tracer development. Across 5 days, we conducted a total of 117 experiments, studying 36 distinct conditions, while utilizing <15 mg of total organoboron precursor. Compared to the original report in which the radiochemical yield (RCY) was 4.4 ± 0.5% (n = 5), the optimized droplet condition provided a substantial improvement in RCY (52 ± 8%, n = 4) and showed excellent radiochemical purity (100%) and molar activity (77-854 GBq μmol-1), using a starting activity of 0.2-1.45 GBq. Furthermore, we showed for the first time a translation of the optimized microscale conditions to a vial-based method. With similar starting activity (0.2-1.44 GBq), the translated synthesis exhibited a comparable RCY of 50 ± 10% (n = 4) while maintaining excellent radiochemical purity (100%) and acceptable molar activity (20-46 GBq μmol-1). The successful translation to vial-based reactions ensures wider applicability of the optimized synthesis by leveraging widely available commercial vial-based synthesis modules.
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Affiliation(s)
- Yingqing Lu
- Crump Institute for Molecular Imaging, University of California Los Angeles (UCLA), Los Angeles, CA, USA.
- Department of Molecular & Medical Pharmacology, UCLA, Los Angeles, CA, USA
- Physics and Biology in Medicine Interdepartmental Graduate Program, UCLA, Los Angeles, CA, USA
| | - Yingfang He
- Center for Radiopharmaceutical Sciences, Institute of Pharmaceutical Sciences, Department of Chemistry and Applied Biosciences, ETH Zurich, Zurich, Switzerland
| | - Roger Schibli
- Center for Radiopharmaceutical Sciences, Institute of Pharmaceutical Sciences, Department of Chemistry and Applied Biosciences, ETH Zurich, Zurich, Switzerland
| | - Linjing Mu
- Center for Radiopharmaceutical Sciences, Institute of Pharmaceutical Sciences, Department of Chemistry and Applied Biosciences, ETH Zurich, Zurich, Switzerland
| | - R Michael van Dam
- Crump Institute for Molecular Imaging, University of California Los Angeles (UCLA), Los Angeles, CA, USA.
- Department of Molecular & Medical Pharmacology, UCLA, Los Angeles, CA, USA
- Physics and Biology in Medicine Interdepartmental Graduate Program, UCLA, Los Angeles, CA, USA
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3
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Haveman LYF, Vugts DJ, Windhorst AD. State of the art procedures towards reactive [ 18F]fluoride in PET tracer synthesis. EJNMMI Radiopharm Chem 2023; 8:28. [PMID: 37824021 PMCID: PMC10570257 DOI: 10.1186/s41181-023-00203-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Accepted: 08/03/2023] [Indexed: 10/13/2023] Open
Abstract
BACKGROUND Positron emission tomography (PET) is a powerful, non-invasive preclinical and clinical nuclear imaging technique used in disease diagnosis and therapy assessment. Fluorine-18 is the predominant radionuclide used for PET tracer synthesis. An impressive variety of new 'late-stage' radiolabeling methodologies for the preparation of 18F-labeled tracers has appeared in order to improve the efficiency of the labeling reaction. MAIN BODY Despite these developments, one outstanding challenge into the early key steps of the process remains: the preparation of reactive [18F]fluoride from oxygen-18 enriched water ([18O]H2O). In the last decade, significant changes into the trapping, elution and drying stages have been introduced. This review provides an overview of the strategies and recent developments in the production of reactive [18F]fluoride and its use for radiolabeling. CONCLUSION Improved, modified or even completely new fluorine-18 work-up procedures have been developed in the last decade with widespread use in base-sensitive nucleophilic 18F-fluorination reactions. The many promising developments may lead to a few standardized drying methodologies for the routine production of a broad scale of PET tracers.
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Affiliation(s)
- Lizeth Y F Haveman
- Radiology and Nuclear Medicine, Amsterdam UMC, Vrije Universiteit Amsterdam, De Boelelaan 1117, Amsterdam, The Netherlands
- Chemistry and Pharmaceutical Sciences, Amsterdam Institute of Molecular and Life Sciences (AIMMS), Amsterdam, The Netherlands
| | - Danielle J Vugts
- Radiology and Nuclear Medicine, Amsterdam UMC, Vrije Universiteit Amsterdam, De Boelelaan 1117, Amsterdam, The Netherlands
- Cancer Center Amsterdam (CCA), Amsterdam, The Netherlands
| | - Albert D Windhorst
- Radiology and Nuclear Medicine, Amsterdam UMC, Vrije Universiteit Amsterdam, De Boelelaan 1117, Amsterdam, The Netherlands.
- Neuroscience Amsterdam, Amsterdam, The Netherlands.
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Kumar A, Joshi RK, Thakur R, Kumar D, Nagaraj C, Kumar P. Development of an economical method to synthesize O-(2-[ 18 F]fluoroethyl)-L-tyrosine ( 18 FFET). J Labelled Comp Radiopharm 2023; 66:345-352. [PMID: 37408511 DOI: 10.1002/jlcr.4052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 06/16/2023] [Accepted: 06/19/2023] [Indexed: 07/07/2023]
Abstract
Positron emission tomography (PET) using O-(2-[18 F]fluoroethyl)-L-tyrosine ([18 F]FET) has shown great success in differentiating tumor recurrence from necrosis. In this study, we are reporting the experience of synthesis [18 F]FET by varying the concentration of TET precursor in different chemistry modules. TET precursor (2-10 mg) was used for the synthesis of [18 F]FET in an automated (MX Tracerlab) module (n = 6) and semiautomated (FX2N Tracerlab) module (n = 19). The quality control was performed for all the preparations. For human imaging, 220 ± 50 MBq of [18 F]FET was briefly injected into the patient to acquire PET-MR images. The radiochemical purity was greater than 95% for the final product in both modules. The decay corrected average yield was 10.7 ± 4.7% (10 mg, n = 3) and 8.2 ± 2.6% (2 mg, n = 3) with automated chemistry module and 36.7 ± 7.3% (8-10 mg, n = 12), 26.4 ± 3.1% (5-7 mg, n = 4), and 35.1 ± 3.8% (2-4 mg, n = 3) with semiautomated chemistry modules. The PET imaging showed uptake at the lesion site (SUVmax = 7.5 ± 2.6) and concordance with the MR image. The [18 F]FET was produced with a higher radiochemical yield with 2.0 mg of the precursor with substantial yield and is suitable for brain tumor imaging.
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Affiliation(s)
- Aishwarya Kumar
- Department of Neuroimaging and Interventional Radiology (NI&IR), National Institute of Mental Health & Neurosciences (NIMHANS), Bengaluru, Karnataka, India
| | - Raman Kumar Joshi
- Department of Neuroimaging and Interventional Radiology (NI&IR), National Institute of Mental Health & Neurosciences (NIMHANS), Bengaluru, Karnataka, India
| | - Riptee Thakur
- Department of Neuroimaging and Interventional Radiology (NI&IR), National Institute of Mental Health & Neurosciences (NIMHANS), Bengaluru, Karnataka, India
| | - Dinesh Kumar
- Department of Neuroimaging and Interventional Radiology (NI&IR), National Institute of Mental Health & Neurosciences (NIMHANS), Bengaluru, Karnataka, India
| | - Chandana Nagaraj
- Department of Neuroimaging and Interventional Radiology (NI&IR), National Institute of Mental Health & Neurosciences (NIMHANS), Bengaluru, Karnataka, India
| | - Pardeep Kumar
- Department of Neuroimaging and Interventional Radiology (NI&IR), National Institute of Mental Health & Neurosciences (NIMHANS), Bengaluru, Karnataka, India
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Morito T, Harada R, Iwata R, Ishikawa Y, Okamura N, Kudo Y, Furumoto S, Yanai K, Tashiro M. Evaluation of 18F labeled glial fibrillary acidic protein binding nanobody and its brain shuttle peptide fusion proteins using a neuroinflammation rat model. PLoS One 2023; 18:e0287047. [PMID: 37315033 DOI: 10.1371/journal.pone.0287047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2022] [Accepted: 05/27/2023] [Indexed: 06/16/2023] Open
Abstract
Astrogliosis is a crucial feature of neuroinflammation and is characterized by the significant upregulation of glial fibrillary acidic protein (GFAP) expression. Hence, visualizing GFAP in the living brain of patients with damaged central nervous system using positron emission tomography (PET) is of great importance, and it is expected to depict neuroinflammation more directly than existing neuroinflammation imaging markers. However, no PET radiotracers for GFAP are currently available. Therefore, neuroimaging with antibody-like affinity proteins could be a viable strategy for visualizing imaging targets that small molecules rarely recognize, such as GFAP, while we need to overcome the challenges of slow clearance and low brain permeability. The E9 nanobody, a small-affinity protein with high affinity and selectivity for GFAP, was utilized in this study. E9 was engineered by fusing a brain shuttle peptide that facilitates blood-brain barrier permeation via two different types of linker domains: E9-GS-ApoE (EGA) and E9-EAK-ApoE (EEA). E9, EGA and EEA were radiolabeled with fluorine-18 using cell-free protein radiosynthesis. In vitro autoradiography showed that all radiolabeled proteins exhibited a significant difference in neuroinflammation in the brain sections created from a rat model constructed by injecting lipopolysaccharide (LPS) into the unilateral striatum of wildtype rats, and an excess competitor displaced their binding. However, exploratory in vivo PET imaging and ex vivo biodistribution studies in the rat model failed to distinguish neuroinflammatory lesions within 3 h of 18F-EEA intravenous injection. This study contributes to a better understanding of the characteristics of small-affinity proteins fused with a brain shuttle peptide for further research into the use of protein molecules as PET tracers for imaging neuropathology.
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Affiliation(s)
- Takahiro Morito
- Division of Cyclotron Nuclear Medicine, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
- Department of Pharmacology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
| | - Ryuichi Harada
- Department of Pharmacology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
- Institute of Development, Aging and Cancer, Tohoku University, Sendai, Miyagi, Japan
| | - Ren Iwata
- Division of Radiopharmaceutical Chemistry, Cyclotron and Radioisotope Center, Tohoku University, Sendai, Miyagi, Japan
| | - Yoichi Ishikawa
- Division of Radiopharmaceutical Chemistry, Cyclotron and Radioisotope Center, Tohoku University, Sendai, Miyagi, Japan
| | - Nobuyuki Okamura
- Division of Pharmacology, Faculty of Medicine, Tohoku Medical and Pharmaceutical University, Sendai, Miyagi, Japan
| | - Yukitsuka Kudo
- Institute of Development, Aging and Cancer, Tohoku University, Sendai, Miyagi, Japan
| | - Shozo Furumoto
- Division of Radiopharmaceutical Chemistry, Cyclotron and Radioisotope Center, Tohoku University, Sendai, Miyagi, Japan
| | - Kazuhiko Yanai
- Division of Cyclotron Nuclear Medicine, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
- Department of Pharmacology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
| | - Manabu Tashiro
- Division of Cyclotron Nuclear Medicine, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
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N‐
Alkyl 3‐aminobut‐2‐enenitrile as a Non‐radioactive Side Product in Nucleophilic
18
F‐Fluorination. ChemistrySelect 2021. [DOI: 10.1002/slct.202100723] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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7
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Lerdsirisuk P, Harada R, Hayakawa Y, Shimizu Y, Ishikawa Y, Iwata R, Kudo Y, Okamura N, Furumoto S. Synthesis and evaluation of 2-pyrrolopyridinylquinoline derivatives as selective tau PET tracers for the diagnosis of Alzheimer's disease. Nucl Med Biol 2021; 93:11-18. [PMID: 33221641 DOI: 10.1016/j.nucmedbio.2020.10.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 09/22/2020] [Accepted: 10/17/2020] [Indexed: 11/21/2022]
Abstract
INTRODUCTION [18F]THK-5351 was originally developed as a positron emission tomography (PET) imaging tracer for the detection of accumulated tau proteins, the pathological hallmark of Alzheimer's disease (AD). However, clinical studies of [18F]THK-5351 revealed the existence of off-target binding to monoamine oxidase-B (MAO-B). To overcome this off-target binding, in this work, we synthesized and evaluated 2-pyrrolopyridinylquinoline (PPQ) derivatives as selective tau PET imaging tracers. METHODS The core structure of PPQ derivatives was synthesized mainly using the Buchwald-Hartwig amination coupling reaction. All derivatives were evaluated for binding affinity towards tau and MAO-B by in vitro competitive binding assay. Radiosynthesis of PPQ derivatives was performed by 18F-radiolabeling of their tosylate precursors with activated [18F]KF/Kryptofix222 complex in dimethylsulfoxide by heating at 110 °C for 10 min. The biological properties of these [18F]PPQ derivatives were characterized by in vitro autoradiography of postmortem AD brain sections and by assay of ex vivo biodistribution in mice. RESULTS The PPQ derivatives were synthesized, with yields of 49-84%. In vitro competitive binding assay revealed that two novel PPQ derivatives-PPQ8 and PPQ9-demonstrated high binding affinity for tau (IC50 = 4.9 and 6.9 nM, respectively). The radiosynthesis of [18F]PPQ8 and [18F]PPQ9 yielded 1.4% and 50.1% isolated non-decay corrected radiochemical yield, respectively, with >99% radiochemical purity. The molar radioactivities of [18F]PPQ8 and [18F]PPQ9 were 16.9 and 64.8 GBq/μmol, respectively. The in vitro and ex vivo biological characterization of [18F]PPQ8 and [18F]PPQ9 revealed that these tracers were selective for tau in AD brain sections without off-target binding, and they furthermore demonstrated brain uptake in normal mice. CONCLUSIONS 18F-labeled PPQ derivatives improved binding affinity and selectivity for tau aggregates in AD. Further structural optimization to improve pharmacokinetics for potent tau PET imaging tracers is required.
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Affiliation(s)
- Pradith Lerdsirisuk
- Radiopharmaceutical Chemistry, Graduate School of Pharmaceutical Science, Tohoku University, Sendai 980-8578, Japan; Cyclotron and Radioisotope Center (CYRIC), Tohoku University, Sendai 980-8578, Japan
| | - Ryuichi Harada
- Department of Pharmacology, Graduate School of Medicine, Tohoku University, Sendai 980-0872, Japan; Department of Gerontology and Geriatrics, Division of Brain Science, Institute of Development Aging and Cancer (IDAC), Tohoku University, Sendai 980-0872, Japan
| | - Yoshimi Hayakawa
- Radiopharmaceutical Chemistry, Graduate School of Pharmaceutical Science, Tohoku University, Sendai 980-8578, Japan; Cyclotron and Radioisotope Center (CYRIC), Tohoku University, Sendai 980-8578, Japan
| | - Yuki Shimizu
- Cyclotron and Radioisotope Center (CYRIC), Tohoku University, Sendai 980-8578, Japan; Department of Pharmacy, Faculty of Pharmaceutical Science, Tohoku University, Sendai 980-8578, Japan
| | - Yoichi Ishikawa
- Cyclotron and Radioisotope Center (CYRIC), Tohoku University, Sendai 980-8578, Japan
| | - Ren Iwata
- Cyclotron and Radioisotope Center (CYRIC), Tohoku University, Sendai 980-8578, Japan
| | - Yukitsuka Kudo
- Department of Gerontology and Geriatrics, Division of Brain Science, Institute of Development Aging and Cancer (IDAC), Tohoku University, Sendai 980-0872, Japan
| | - Nobuyuki Okamura
- Cyclotron and Radioisotope Center (CYRIC), Tohoku University, Sendai 980-8578, Japan; Division of Pharmocology, Faculty of Medicine, Tohoku Medical and Pharmaceutical University, Sendai 983-8512, Japan
| | - Shozo Furumoto
- Cyclotron and Radioisotope Center (CYRIC), Tohoku University, Sendai 980-8578, Japan.
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8
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Synthesis and pharmacokinetic characterisation of a fluorine-18 labelled brain shuttle peptide fusion dimeric affibody. Sci Rep 2021; 11:2588. [PMID: 33510301 PMCID: PMC7844286 DOI: 10.1038/s41598-021-82037-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Accepted: 01/14/2021] [Indexed: 11/08/2022] Open
Abstract
Brain positron emission tomography (PET) imaging with radiolabelled proteins is an emerging concept that potentially enables visualization of unique molecular targets in the brain. However, the pharmacokinetics and protein radiolabelling methods remain challenging. Here, we report the performance of an engineered, blood-brain barrier (BBB)-permeable affibody molecule that exhibits rapid clearance from the brain, which was radiolabelled using a unique fluorine-18 labelling method, a cell-free protein radiosynthesis (CFPRS) system. AS69, a small (14 kDa) dimeric affibody molecule that binds to the monomeric and oligomeric states of α-synuclein, was newly designed for brain delivery with an apolipoprotein E (ApoE)-derived brain shuttle peptide as AS69-ApoE (22 kDa). The radiolabelled products 18F-AS69 and 18F-AS69-ApoE were successfully synthesised using the CFPRS system. Notably, 18F-AS69-ApoE showed higher BBB permeability than 18F-AS69 in an ex vivo study at 10 and 30 min post injection and was partially cleared from the brain at 120 min post injection. These results suggest that small, a brain shuttle peptide-fused fluorine-18 labelled protein binders can potentially be utilised for brain molecular imaging.
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Iwata R, Terasaki K, Ishikawa Y, Harada R, Furumoto S, Yanai K, Pascali C. A concentration-based microscale method for 18F-nucleophilic substitutions and its testing on the one-pot radiosynthesis of [ 18F]FET and [ 18F]fallypride. Appl Radiat Isot 2020; 166:109361. [PMID: 32877862 DOI: 10.1016/j.apradiso.2020.109361] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 07/23/2020] [Accepted: 07/27/2020] [Indexed: 10/23/2022]
Abstract
When applied to a radiosynthesis, a microscale approach can help to save precursor and improve yields. Thus, a 5-10 μL microscale method based on a concentration procedure was developed and applied to the radiosynthesis of [18F]FET and [18F]fallypride. In spite of using an amount of precursor ca. 100 times smaller, radiochemical yields were comparable or even higher than those reported in literature. Because of the very low reaction volumes, the possible effects of concentrated dose of activity and carrier fluoride were also investigated.
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Affiliation(s)
- Ren Iwata
- Cyclotron and Radioisotope Center, Tohoku University, Sendai, Japan
| | | | - Yoichi Ishikawa
- Cyclotron and Radioisotope Center, Tohoku University, Sendai, Japan
| | - Ryuichi Harada
- Graduate School of Medicine, Tohoku University, Sendai, Japan
| | - Shozo Furumoto
- Cyclotron and Radioisotope Center, Tohoku University, Sendai, Japan
| | - Kazuhiko Yanai
- Graduate School of Medicine, Tohoku University, Sendai, Japan
| | - Claudio Pascali
- Fondazione IRCCS Istituto Nazionale dei Tumori, V. Venezian, 1, Milan, 20133, Italy.
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Orlovskaya V, Antuganov D, Fedorova O, Timofeev V, Krasikova R. Tetrabutylammonium tosylate as inert phase-transfer catalyst: The key to high efficiency SN2 radiofluorinations. Appl Radiat Isot 2020; 163:109195. [DOI: 10.1016/j.apradiso.2020.109195] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Revised: 03/26/2020] [Accepted: 04/20/2020] [Indexed: 12/14/2022]
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11
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Harada R, Hayakawa Y, Ezura M, Lerdsirisuk P, Du Y, Ishikawa Y, Iwata R, Shidahara M, Ishiki A, Kikuchi A, Arai H, Kudo Y, Yanai K, Furumoto S, Okamura N. 18F-SMBT-1: A Selective and Reversible PET Tracer for Monoamine Oxidase-B Imaging. J Nucl Med 2020; 62:253-258. [PMID: 32646880 DOI: 10.2967/jnumed.120.244400] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Accepted: 06/15/2020] [Indexed: 11/16/2022] Open
Abstract
Reactive astrocytes play a key role in the pathogenesis of various neurodegenerative diseases. Monoamine oxidase-B (MAO-B) is one of the promising targets for the imaging of astrogliosis in the human brain. A novel selective and reversible MAO-B tracer, (S)-(2-methylpyrid-5-yl)-6-[(3-18F-fluoro-2-hydroxy)propoxy]quinoline (18F-SMBT-1), was successfully developed via lead optimization from the first-generation tau PET tracer 18F-THK-5351. Methods: SMBT-1 was radiolabeled with 18F using the corresponding precursor. The binding affinity of radiolabeled compounds to MAO-B was assessed using saturation and competitive binding assays. The binding selectivity of 18F-SMBT-1 to MAO-B was evaluated by autoradiography of frozen human brain tissues. The pharmacokinetics and metabolism were assessed in normal mice after intravenous administration of 18F-SMBT-1. A 14-d toxicity study after the intravenous administration of 18F-SMBT-1 was performed using rats and mice. Results: In vitro binding assays demonstrated a high binding affinity of 18F-SMBT-1 to MAO-B (dissociation constant, 3.7 nM). In contrast, it showed low binding affinity to MAO-A and protein aggregates such as amyloid-β and tau fibrils. Autoradiographic analysis showed higher amounts of 18F-SMBT-1 binding in the Alzheimer disease brain sections than in the control brain sections. 18F-SMBT-1 binding was completely displaced with the reversible MAO-B inhibitor lazabemide, demonstrating the high selectivity of 18F-SMBT-1 for MAO-B. Furthermore, 18F-SMBT-1 showed a high uptake by brain, rapid washout, and no radiolabeled metabolites in the brain of normal mice. 18F-SMBT-1 showed no significant binding to various receptors, ion channels, or transporters, and no toxic effects related to its administration were observed in mice and rats. Conclusion: 18F-SMBT-1 is a promising and selective MAO-B PET tracer candidate, which would be useful for quantitative monitoring of astrogliosis in the human brain.
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Affiliation(s)
- Ryuichi Harada
- Department of Pharmacology, Tohoku University School of Medicine, Sendai, Japan .,Department of Geriatrics and Gerontology, Division of Brain Sciences, Institute of Development, Aging, and Cancer, Tohoku University, Sendai, Japan
| | - Yoshimi Hayakawa
- Cyclotron and Radioisotope Center, Tohoku University, Sendai, Japan
| | - Michinori Ezura
- Department of Neurology, Tohoku University Graduate School of Medicine. 1-1 Seiryo-machi, Aoba-ku, Sendai, Japan
| | | | - Yiqing Du
- Department of Pharmacology, Tohoku University School of Medicine, Sendai, Japan
| | - Yoichi Ishikawa
- Cyclotron and Radioisotope Center, Tohoku University, Sendai, Japan
| | - Ren Iwata
- Cyclotron and Radioisotope Center, Tohoku University, Sendai, Japan
| | - Miho Shidahara
- Department of Quantum Science and Energy Engineering, Tohoku University, Sendai, Japan; and
| | - Aiko Ishiki
- Department of Geriatrics and Gerontology, Division of Brain Sciences, Institute of Development, Aging, and Cancer, Tohoku University, Sendai, Japan
| | - Akio Kikuchi
- Department of Neurology, Tohoku University Graduate School of Medicine. 1-1 Seiryo-machi, Aoba-ku, Sendai, Japan
| | - Hiroyuki Arai
- Department of Geriatrics and Gerontology, Division of Brain Sciences, Institute of Development, Aging, and Cancer, Tohoku University, Sendai, Japan
| | - Yukitsuka Kudo
- Department of Geriatrics and Gerontology, Division of Brain Sciences, Institute of Development, Aging, and Cancer, Tohoku University, Sendai, Japan
| | - Kazuhiko Yanai
- Department of Pharmacology, Tohoku University School of Medicine, Sendai, Japan.,Cyclotron and Radioisotope Center, Tohoku University, Sendai, Japan
| | - Shozo Furumoto
- Cyclotron and Radioisotope Center, Tohoku University, Sendai, Japan
| | - Nobuyuki Okamura
- Cyclotron and Radioisotope Center, Tohoku University, Sendai, Japan.,Division of Pharmacology, Faculty of Medicine, Tohoku Medical and Pharmaceutical University, Sendai, Japan
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12
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Fully automated radiosynthesis and quality control of estrogen receptor targeting radiopharmaceutical 16α-[18F]fluoroestradiol ([18F]FES) for human breast cancer imaging. Appl Radiat Isot 2020; 160:109109. [DOI: 10.1016/j.apradiso.2020.109109] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2019] [Revised: 02/10/2020] [Accepted: 02/27/2020] [Indexed: 11/17/2022]
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13
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Wang J, van Dam RM. High-Efficiency Production of Radiopharmaceuticals via Droplet Radiochemistry: A Review of Recent Progress. Mol Imaging 2020; 19:1536012120973099. [PMID: 33296272 PMCID: PMC7731702 DOI: 10.1177/1536012120973099] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 09/02/2020] [Accepted: 10/12/2020] [Indexed: 12/13/2022] Open
Abstract
New platforms are enabling radiochemistry to be carried out in tiny, microliter-scale volumes, and this capability has enormous benefits for the production of radiopharmaceuticals. These droplet-based technologies can achieve comparable or better yields compared to conventional methods, but with vastly reduced reagent consumption, shorter synthesis time, higher molar activity (even for low activity batches), faster purification, and ultra-compact system size. We review here the state of the art of this emerging direction, summarize the radiotracers and prosthetic groups that have been synthesized in droplet format, describe recent achievements in scaling up activity levels, and discuss advantages and limitations and the future outlook of these innovative devices.
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Affiliation(s)
- Jia Wang
- Crump Institute for Molecular Imaging and Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA, Los Angeles, CA, USA
| | - R. Michael van Dam
- Crump Institute for Molecular Imaging and Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA, Los Angeles, CA, USA
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14
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Lisova K, Chen BY, Wang J, Fong KMM, Clark PM, van Dam RM. Rapid, efficient, and economical synthesis of PET tracers in a droplet microreactor: application to O-(2-[ 18F]fluoroethyl)-L-tyrosine ([ 18F]FET). EJNMMI Radiopharm Chem 2019; 5:1. [PMID: 31893318 PMCID: PMC6938530 DOI: 10.1186/s41181-019-0082-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Accepted: 11/21/2019] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Conventional scale production of small batches of PET tracers (e.g. for preclinical imaging) is an inefficient use of resources. Using O-(2-[18F]fluoroethyl)-L-tyrosine ([18F]FET), we demonstrate that simple microvolume radiosynthesis techniques can improve the efficiency of production by consuming tiny amounts of precursor, and maintaining high molar activity of the tracers even with low starting activity. PROCEDURES The synthesis was carried out in microvolume droplets manipulated on a disposable patterned silicon "chip" affixed to a heater. A droplet of [18F]fluoride containing TBAHCO3 was first deposited onto a chip and dried at 100 °C. Subsequently, a droplet containing 60 nmol of precursor was added to the chip and the fluorination reaction was performed at 90 °C for 5 min. Removal of protecting groups was accomplished with a droplet of HCl heated at 90 °C for 3 min. Finally, the crude product was collected in a methanol-water mixture, purified via analytical-scale radio-HPLC and formulated in saline. As a demonstration, using [18F]FET produced on the chip, we prepared aliquots with different molar activities to explore the impact on preclinical PET imaging of tumor-bearing mice. RESULTS The microdroplet synthesis exhibited an overall decay-corrected radiochemical yield of 55 ± 7% (n = 4) after purification and formulation. When automated, the synthesis could be completed in 35 min. Starting with < 370 MBq of activity, ~ 150 MBq of [18F]FET could be produced, sufficient for multiple in vivo experiments, with high molar activities (48-119 GBq/μmol). The demonstration imaging study revealed the uptake of [18F]FET in subcutaneous tumors, but no significant differences in tumor uptake as a result of molar activity differences (ranging 0.37-48 GBq/μmol) were observed. CONCLUSIONS A microdroplet synthesis of [18F]FET was developed demonstrating low reagent consumption, high yield, and high molar activity. The approach can be expanded to tracers other than [18F]FET, and adapted to produce higher quantities of the tracer sufficient for clinical PET imaging.
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Affiliation(s)
- Ksenia Lisova
- Physics in Biology and Medicine Interdepartmental Graduate Program, University of California, Los Angeles, Los Angeles, CA, USA
- Crump Institute for Molecular Imaging, University of California, Los Angeles, Los Angeles, CA, USA
- Department of Molecular & Medical Pharmacology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Bao Ying Chen
- Physics in Biology and Medicine Interdepartmental Graduate Program, University of California, Los Angeles, Los Angeles, CA, USA
- Crump Institute for Molecular Imaging, University of California, Los Angeles, Los Angeles, CA, USA
- Department of Molecular & Medical Pharmacology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Jia Wang
- Crump Institute for Molecular Imaging, University of California, Los Angeles, Los Angeles, CA, USA
- Department of Molecular & Medical Pharmacology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
- Department of Bioengineering, University of California, Los Angeles, Los Angeles, CA, USA
| | - Kelly Mun-Ming Fong
- Crump Institute for Molecular Imaging, University of California, Los Angeles, Los Angeles, CA, USA
- Department of Molecular & Medical Pharmacology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Peter M Clark
- Physics in Biology and Medicine Interdepartmental Graduate Program, University of California, Los Angeles, Los Angeles, CA, USA
- Crump Institute for Molecular Imaging, University of California, Los Angeles, Los Angeles, CA, USA
- Department of Molecular & Medical Pharmacology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - R Michael van Dam
- Physics in Biology and Medicine Interdepartmental Graduate Program, University of California, Los Angeles, Los Angeles, CA, USA.
- Crump Institute for Molecular Imaging, University of California, Los Angeles, Los Angeles, CA, USA.
- Department of Molecular & Medical Pharmacology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA.
- Department of Bioengineering, University of California, Los Angeles, Los Angeles, CA, USA.
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15
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Wang J, Chao PH, van Dam RM. Ultra-compact, automated microdroplet radiosynthesizer. LAB ON A CHIP 2019; 19:2415-2424. [PMID: 31187109 PMCID: PMC7416997 DOI: 10.1039/c9lc00438f] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Application of microfluidics offers numerous advantages in the field of radiochemistry and could enable dramatic reductions in the cost of producing radiotracers for positron emission tomography (PET). Droplet-based microfluidics, in particular, requires only microgram quantities of expensive precursors and reagents (compared to milligram used in conventional radiochemistry systems), and occupies a more compact footprint (potentially eliminating the need for specialized shielding facilities, i.e. hot cells). However, the reported platforms for droplet radiosynthesis have several drawbacks, including high cost/complexity of microfluidic reactors, requirement for manual intervention (e.g. for adding reagents), or difficulty in precise control of droplet processes. We describe here a platform based on a particularly simple chip, where reactions take place atop a hydrophobic substrate patterned with a circular hydrophilic liquid trap. The overall supporting hardware (heater, rotating carousel of reagent dispensers, etc.) is very simple and the whole system could be packaged into a very compact format (about the size of a coffee cup). We demonstrate the consistent synthesis of [18F]fallypride with high yield, and show that protocols optimized using a high-throughput optimization platform we have developed can be readily translated to this device with no changes or re-optimization. We are currently exploring the use of this platform for routine production of a variety of 18F-labeled tracers for preclinical imaging and for production of tracers in clinically-relevant amounts by integrating the system with an upstream radionuclide concentrator.
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Affiliation(s)
- Jia Wang
- Crump Institute for Molecular Imaging and Department of Molecular & Medical Pharmacology, David Geffen School of Medicine, University of California at Los Angeles (UCLA), Los Angeles, CA, USA. and Department of Bioengineering, UCLA, Los Angeles, CA, USA
| | - Philip H Chao
- Crump Institute for Molecular Imaging and Department of Molecular & Medical Pharmacology, David Geffen School of Medicine, University of California at Los Angeles (UCLA), Los Angeles, CA, USA. and Department of Bioengineering, UCLA, Los Angeles, CA, USA
| | - R Michael van Dam
- Crump Institute for Molecular Imaging and Department of Molecular & Medical Pharmacology, David Geffen School of Medicine, University of California at Los Angeles (UCLA), Los Angeles, CA, USA. and Department of Bioengineering, UCLA, Los Angeles, CA, USA
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16
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Rios A, Wang J, Chao PH, van Dam RM. A novel multi-reaction microdroplet platform for rapid radiochemistry optimization. RSC Adv 2019; 9:20370-20374. [PMID: 35514735 PMCID: PMC9065505 DOI: 10.1039/c9ra03639c] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Accepted: 06/17/2019] [Indexed: 12/20/2022] Open
Abstract
During the development of novel tracers for positron emission tomography (PET), the optimization of the synthesis is hindered by practical limitations on the number of experiments that can be performed per day. Here we present a microliter droplet chip that contains multiple sites (4 or 16) to perform reactions simultaneously under the same or different conditions to accelerate radiosynthesis optimization. Multi-reaction microdroplet chip enables rapid radiotracer optimization for positron emission tomography.![]()
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Affiliation(s)
- Alejandra Rios
- Crump Institute of Molecular Imaging, University of California Los Angeles (UCLA) Los Angeles CA USA .,Physics and Biology in Medicine Interdepartmental Graduate Program, UCLA USA
| | - Jia Wang
- Crump Institute of Molecular Imaging, University of California Los Angeles (UCLA) Los Angeles CA USA .,Department of Bioengineering, UCLA USA
| | - Philip H Chao
- Crump Institute of Molecular Imaging, University of California Los Angeles (UCLA) Los Angeles CA USA .,Department of Bioengineering, UCLA USA
| | - R Michael van Dam
- Crump Institute of Molecular Imaging, University of California Los Angeles (UCLA) Los Angeles CA USA .,Physics and Biology in Medicine Interdepartmental Graduate Program, UCLA USA.,Department of Bioengineering, UCLA USA.,Department of Molecular & Medical Pharmacology, David Geffen School of Medicine, UCLA USA
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17
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Bogni A, Laera L, Cucchi C, Iwata R, Seregni E, Pascali C. An improved automated one-pot synthesis of O-(2-[18F]fluoroethyl)-L-tyrosine ([18F]FET) based on a purification by cartridges. Nucl Med Biol 2019; 72-73:11-19. [DOI: 10.1016/j.nucmedbio.2019.05.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Revised: 05/09/2019] [Accepted: 05/14/2019] [Indexed: 10/26/2022]
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18
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Chao PH, Lazari M, Hanet S, Narayanam MK, Murphy JM, van Dam RM. Automated concentration of [ 18F]fluoride into microliter volumes. Appl Radiat Isot 2018; 141:138-148. [PMID: 30243135 PMCID: PMC6502507 DOI: 10.1016/j.apradiso.2018.06.017] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 06/07/2018] [Accepted: 06/20/2018] [Indexed: 11/23/2022]
Abstract
Concentration of [18F]fluoride has been mentioned in literature, however, reports have lacked details about system designs, operation, and performance. Here, we describe in detail a compact, fast, fully-automated concentration system based on a micro-sized strong anion exchange cartridge. The concentration of radionuclides enables scaled-up microfluidic synthesis. Our system can also be used to provide highly concentrated [18F]fluoride with minimal water content. We demonstrate how the concentrator can produce varying concentrations of [18F]fluoride for the macroscale synthesis of N-boc-5-[18F]fluoroindole without an azeotropic drying process, while enabling high starting radioactivity. By appropriate choice of solid-phase resin, flow conditions, and eluent solution, we believe this approach can be extended beyond [18F]fluoride to other radionuclides.
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Affiliation(s)
- Philip H Chao
- Department of Bioengineering, Henry Samueli School of Engineering, UCLA, Los Angeles, CA 90095, USA; Crump Institute for Molecular Imaging, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA; Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA
| | - Mark Lazari
- Department of Bioengineering, Henry Samueli School of Engineering, UCLA, Los Angeles, CA 90095, USA; Crump Institute for Molecular Imaging, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA; Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA
| | - Sebastian Hanet
- Crump Institute for Molecular Imaging, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA; Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA
| | - Maruthi Kumar Narayanam
- Crump Institute for Molecular Imaging, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA; Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA
| | - Jennifer M Murphy
- Crump Institute for Molecular Imaging, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA; Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA
| | - R Michael van Dam
- Department of Bioengineering, Henry Samueli School of Engineering, UCLA, Los Angeles, CA 90095, USA; Crump Institute for Molecular Imaging, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA; Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA
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Site-Specific Labeling of F-18 Proteins Using a Supplemented Cell-Free Protein Synthesis System and O-2-[18F]Fluoroethyl-L-Tyrosine: [18F]FET-HER2 Affibody Molecule. Mol Imaging Biol 2018; 21:529-537. [DOI: 10.1007/s11307-018-1266-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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