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Hirata K, Watanabe S, Kitagawa Y, Kudo K. A Review of Hypoxia Imaging Using 18F-Fluoromisonidazole Positron Emission Tomography. Methods Mol Biol 2024; 2755:133-140. [PMID: 38319574 DOI: 10.1007/978-1-0716-3633-6_9] [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] [Indexed: 02/07/2024]
Abstract
Tumor hypoxia is an essential factor related to malignancy, prognosis, and resistance to treatment. Positron emission tomography (PET) is a modality that visualizes the distribution of radiopharmaceuticals administered into the body. PET imaging with [18F]fluoromisonidazole ([18F]FMISO) identifies hypoxic tissues. Unlike [18F]fluorodeoxyglucose ([18F]FDG)-PET, fasting is not necessary for [18F]FMISO-PET, but the waiting time from injection to image acquisition needs to be relatively long (e.g., 2-4 h). [18F]FMISO-PET images can be displayed on an ordinary commercial viewer on a personal computer (PC). While visual assessment is fundamental, various quantitative indices such as tumor-to-muscle ratio have also been proposed. Several novel hypoxia tracers have been invented to compensate for the limitations of [18F]FMISO.
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Affiliation(s)
- Kenji Hirata
- Department of Diagnostic Imaging, Graduate School of Medicine, Hokkaido University, Sapporo, Japan.
- Department of Nuclear Medicine, Hokkaido University Hospital, Sapporo, Japan.
- Global Center for Biomedical Science and Engineering, Faculty of Medicine, Hokkaido University, Sapporo, Japan.
| | - Shiro Watanabe
- Department of Diagnostic Imaging, Graduate School of Medicine, Hokkaido University, Sapporo, Japan
- Department of Nuclear Medicine, Hokkaido University Hospital, Sapporo, Japan
- Global Center for Biomedical Science and Engineering, Faculty of Medicine, Hokkaido University, Sapporo, Japan
| | - Yoshimasa Kitagawa
- Oral Diagnosis and Medicine, Department of Oral Pathobiological Science, Graduate School of Dental Medicine, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Kohsuke Kudo
- Department of Diagnostic Imaging, Graduate School of Medicine, Hokkaido University, Sapporo, Japan
- Department of Nuclear Medicine, Hokkaido University Hospital, Sapporo, Japan
- Department of Diagnostic and Interventional Radiology, Hokkaido University Hospital, Sapporo, Japan
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Sasaki I, Tada M, Liu Z, Tatsuta M, Okura T, Aoki M, Takahashi K, Ishioka NS, Watanabe S, Tanaka H. 1-( N, N-Dialkylcarbamoyl)-1,1-difluoromethanesulfonyl ester as a stable and effective precursor for a neopentyl labeling group with astatine-211. Org Biomol Chem 2023; 21:7467-7472. [PMID: 37670575 DOI: 10.1039/d3ob00944k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/07/2023]
Abstract
Radiohalogens with a short half-life are useful radioisotopes for radiotheranostics. Astatine-211 is an α-emitting radiohalogen and is expected to be applicable to targeted α therapy. A neopentyl labeling group is an effective hydrophilic labeling unit for various radiohalogens, which includes 211At. In this study, a 1-(N,N-dialkylcarbamoyl)-1,1-difluoromethanesulfonyl (CDf) ester was developed as a stable precursor for labeling with 211At, 77Br and 125I through a neopentyl labeling group. The CDf ester remained stable in an acetonitrile solution at room temperature and enabled the successful syntheses of 211At-labeled compounds in a highly radiochemical conversion in the presence of K2CO3. 77Br- and 125I-labeled compounds can be prepared from the CDf ester without a base. The utility of the CDf ester was demonstrated in the synthesis of a benzylguanidine with a neopentyl 211At-labeling group. The developed method afforded a 32% radiochemical yield of 211At-labeled benzylguanidine. However, a partial deastatination was observed under acidic conditions during the removal of an N-Boc protecting group. Deprotecting these groups under milder acidic conditions may improve the radiochemical yield. In conclusion, the CDf ester facilitates the syntheses of 211At, 125I and 77Br-labeled compounds that use a neopentyl labeling group for radiotheranostic applications. Further optimization of protecting groups and reaction conditions should enhance the total radiochemical yield of the 211At-labeled compounds.
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Affiliation(s)
- Ichiro Sasaki
- Department of Quantum-Applied Biosciences, Takasaki Institute for Advanced Quantum Science National Institutes for Quantum Science and Technology, 1233 Watanuki-machi, Takasaki, Gunma 370-1292, Japan
| | - Masatoshi Tada
- Department of Chemical Science and Engineering, Tokyo Institute of Technology, 12-12-1-H101 Ookayama, Meguro, Tokyo, 152-8552, Japan.
| | - Ziyun Liu
- Department of Chemical Science and Engineering, Tokyo Institute of Technology, 12-12-1-H101 Ookayama, Meguro, Tokyo, 152-8552, Japan.
| | - Maho Tatsuta
- Department of Chemical Science and Engineering, Tokyo Institute of Technology, 12-12-1-H101 Ookayama, Meguro, Tokyo, 152-8552, Japan.
| | - Takeru Okura
- Department of Chemical Science and Engineering, Tokyo Institute of Technology, 12-12-1-H101 Ookayama, Meguro, Tokyo, 152-8552, Japan.
| | - Miho Aoki
- Advanced Clinical Research Center, Fukushima Global Medical Science Center, Fukushima Medical University, 1 Hikariga-oka, Fukushima, Fukushima 960-1295, Japan
| | - Kazuhiro Takahashi
- Advanced Clinical Research Center, Fukushima Global Medical Science Center, Fukushima Medical University, 1 Hikariga-oka, Fukushima, Fukushima 960-1295, Japan
| | - Noriko S Ishioka
- Department of Quantum-Applied Biosciences, Takasaki Institute for Advanced Quantum Science National Institutes for Quantum Science and Technology, 1233 Watanuki-machi, Takasaki, Gunma 370-1292, Japan
| | - Shigeki Watanabe
- Department of Quantum-Applied Biosciences, Takasaki Institute for Advanced Quantum Science National Institutes for Quantum Science and Technology, 1233 Watanuki-machi, Takasaki, Gunma 370-1292, Japan
| | - Hiroshi Tanaka
- Department of Chemical Science and Engineering, Tokyo Institute of Technology, 12-12-1-H101 Ookayama, Meguro, Tokyo, 152-8552, Japan.
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Bourigault P, Skwarski M, Macpherson RE, Higgins GS, McGowan DR. Timing of hypoxia PET/CT imaging after 18F-fluoromisonidazole injection in non-small cell lung cancer patients. Sci Rep 2022; 12:21746. [PMID: 36526815 PMCID: PMC9758119 DOI: 10.1038/s41598-022-26199-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2022] [Accepted: 12/12/2022] [Indexed: 12/23/2022] Open
Abstract
Positron emission tomography (PET)/computed tomography (CT) using the radiotracer 18F-Fluoromisonidazole (FMISO) has been widely employed to image tumour hypoxia and is of interest to help develop novel hypoxia modifiers and guide radiation treatment planning. Yet, the optimal post-injection (p.i.) timing of hypoxic imaging remains questionable. Therefore, we investigated the correlation between hypoxia-related quantitative values in FMISO-PET acquired at 2 and 4 h p.i. in patients with non-small cell lung cancer (NSCLC). Patients with resectable NSCLC participated in the ATOM clinical trial (NCT02628080) which investigated the hypoxia modifying effects of atovaquone. Two-hour and four-hour FMISO PET/CT images acquired at baseline and pre-surgery visits (n = 58) were compared. Cohort 1 (n = 14) received atovaquone treatment, while cohort 2 (n = 15) did not. Spearman's rank correlation coefficients (ρ) assessed the relationship between hypoxia-related metrics, including standardised uptake value (SUV), tumour-to-blood ratio (TBR), and tumour hypoxic volume (HV) defined by voxels with TBR ≥ 1.4. As the primary imaging-related trial endpoint used to evaluate the action of atovaquone on tumour hypoxia in patients with NSCLC was change in tumour HV from baseline, this was also assessed in patients (n = 20) with sufficient baseline 2- and 4-h scan HV to reliably measure change (predefined as ≥ 1.5 mL). Tumours were divided into four subregions or distance categories: edge, outer, inner, and centre, using MATLAB. In tumours overall, strong correlation (P < 0.001) was observed for SUVmax ρ = 0.87, SUVmean ρ = 0.91, TBRmax ρ = 0.83 and TBRmean ρ = 0.81 between 2- and 4-h scans. Tumour HV was moderately correlated (P < 0.001) with ρ = 0.69 between 2- and 4-h scans. Yet, in tumour subregions, the correlation of HV decreased from the centre ρ = 0.71 to the edge ρ = 0.45 (P < 0.001). SUV, TBR, and HV values were consistently higher on 4-h scans than on 2-h scans, indicating better tracer-to-background contrast. For instance, for TBRmax, the mean, median, and interquartile range were 1.9, 1.7, and 1.6-2.0 2-h p.i., and 2.6, 2.4, and 2.0-3.0 4-h p.i., respectively. Our results support that FMISO-PET scans should be performed at 4 h p.i. to evaluate tumour hypoxia in NSCLC.Trial registration: ClinicalTrials.gov, NCT02628080. Registered 11/12/2015, https://clinicaltrials.gov/ct2/show/NCT02628080 .
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Affiliation(s)
| | - Michael Skwarski
- Department of Oncology, University of Oxford, Oxford, OX3 7DQ, UK
- Department of Oncology, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
- Department of Clinical Oncology, Guy's and St Thomas' NHS Foundation Trust, London, UK
| | - Ruth E Macpherson
- Department of Radiology, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - Geoff S Higgins
- Department of Oncology, University of Oxford, Oxford, OX3 7DQ, UK
- Department of Oncology, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - Daniel R McGowan
- Department of Oncology, University of Oxford, Oxford, OX3 7DQ, UK.
- Department of Medical Physics and Clinical Engineering, Oxford University Hospitals NHS Foundation Trust, Oxford, UK.
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Park J, Young BD, Miller EJ. Potential novel imaging targets of inflammation in cardiac sarcoidosis. J Nucl Cardiol 2022; 29:2171-2187. [PMID: 34734365 DOI: 10.1007/s12350-021-02838-w] [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: 07/24/2021] [Accepted: 09/26/2021] [Indexed: 10/19/2022]
Abstract
Cardiac sarcoidosis (CS) is an inflammatory disease with high morbidity and mortality, with a pathognomonic feature of non-caseating granulomatous inflammation. While 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) is a well-established modality to image inflammation and diagnose CS, there are limitations to its specificity and reproducibility. Imaging focused on the molecular processes of inflammation including the receptors and cellular microenvironments present in sarcoid granulomas provides opportunities to improve upon FDG-PET imaging for CS. This review will highlight the current limitations of FDG-PET imaging for CS while discussing emerging new nuclear imaging molecular targets for the imaging of cardiac sarcoidosis.
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Affiliation(s)
- Jakob Park
- Department of Internal Medicine, Yale School of Medicine, New Haven, CT, USA
| | - Bryan D Young
- Section of Cardiovascular Medicine, Department of Medicine, Yale School of Medicine, 333 Cedar Street, New Haven, CT, 06520, USA
| | - Edward J Miller
- Section of Cardiovascular Medicine, Department of Medicine, Yale School of Medicine, 333 Cedar Street, New Haven, CT, 06520, USA.
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Miller C, Rousseau J, Ramogida CF, Celler A, Rahmim A, Uribe CF. Implications of physics, chemistry and biology for dosimetry calculations using theranostic pairs. Theranostics 2022; 12:232-259. [PMID: 34987643 PMCID: PMC8690938 DOI: 10.7150/thno.62851] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Accepted: 10/18/2021] [Indexed: 12/15/2022] Open
Abstract
Theranostics is an emerging paradigm that combines imaging and therapy in order to personalize patient treatment. In nuclear medicine, this is achieved by using radiopharmaceuticals that target identical molecular targets for both imaging (using emitted gamma rays) and radiopharmaceutical therapy (using emitted beta, alpha or Auger-electron particles) for the treatment of various diseases, such as cancer. If the therapeutic radiopharmaceutical cannot be imaged quantitatively, a “theranostic pair” imaging surrogate can be used to predict the absorbed radiation doses from the therapeutic radiopharmaceutical. However, theranostic dosimetry assumes that the pharmacokinetics and biodistributions of both radiopharmaceuticals in the pair are identical or very similar, an assumption that still requires further validation for many theranostic pairs. In this review, we consider both same-element and different-element theranostic pairs and attempt to determine if factors exist which may cause inaccurate dose extrapolations in theranostic dosimetry, either intrinsic (e.g. chemical differences) or extrinsic (e.g. injecting different amounts of each radiopharmaceutical) to the radiopharmaceuticals. We discuss the basis behind theranostic dosimetry and present common theranostic pairs and their therapeutic applications in oncology. We investigate general factors that could create alterations in the behavior of the radiopharmaceuticals or the quantitative accuracy of imaging them. Finally, we attempt to determine if there is evidence showing some specific pairs as suitable for theranostic dosimetry. We show that there are a variety of intrinsic and extrinsic factors which can significantly alter the behavior among pairs of radiopharmaceuticals, even if they belong to the same chemical element. More research is needed to determine the impact of these factors on theranostic dosimetry estimates and on patient outcomes, and how to correctly account for them.
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Bolcaen J, Kleynhans J, Nair S, Verhoeven J, Goethals I, Sathekge M, Vandevoorde C, Ebenhan T. A perspective on the radiopharmaceutical requirements for imaging and therapy of glioblastoma. Theranostics 2021; 11:7911-7947. [PMID: 34335972 PMCID: PMC8315062 DOI: 10.7150/thno.56639] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Accepted: 03/29/2021] [Indexed: 11/26/2022] Open
Abstract
Despite numerous clinical trials and pre-clinical developments, the treatment of glioblastoma (GB) remains a challenge. The current survival rate of GB averages one year, even with an optimal standard of care. However, the future promises efficient patient-tailored treatments, including targeted radionuclide therapy (TRT). Advances in radiopharmaceutical development have unlocked the possibility to assess disease at the molecular level allowing individual diagnosis. This leads to the possibility of choosing a tailored, targeted approach for therapeutic modalities. Therapeutic modalities based on radiopharmaceuticals are an exciting development with great potential to promote a personalised approach to medicine. However, an effective targeted radionuclide therapy (TRT) for the treatment of GB entails caveats and requisites. This review provides an overview of existing nuclear imaging and TRT strategies for GB. A critical discussion of the optimal characteristics for new GB targeting therapeutic radiopharmaceuticals and clinical indications are provided. Considerations for target selection are discussed, i.e. specific presence of the target, expression level and pharmacological access to the target, with particular attention to blood-brain barrier crossing. An overview of the most promising radionuclides is given along with a validation of the relevant radiopharmaceuticals and theranostic agents (based on small molecules, peptides and monoclonal antibodies). Moreover, toxicity issues and safety pharmacology aspects will be presented, both in general and for the brain in particular.
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Affiliation(s)
- Julie Bolcaen
- Radiobiology, Radiation Biophysics Division, Nuclear Medicine Department, iThemba LABS, Cape Town, South Africa
| | - Janke Kleynhans
- Nuclear Medicine Research Infrastructure NPC, Pretoria, South Africa
- Nuclear Medicine Department, University of Pretoria and Steve Biko Academic Hospital, Pretoria, South Africa
| | - Shankari Nair
- Radiobiology, Radiation Biophysics Division, Nuclear Medicine Department, iThemba LABS, Cape Town, South Africa
| | | | - Ingeborg Goethals
- Ghent University Hospital, Department of Nuclear Medicine, Ghent, Belgium
| | - Mike Sathekge
- Nuclear Medicine Research Infrastructure NPC, Pretoria, South Africa
- Nuclear Medicine Department, University of Pretoria and Steve Biko Academic Hospital, Pretoria, South Africa
| | - Charlot Vandevoorde
- Radiobiology, Radiation Biophysics Division, Nuclear Medicine Department, iThemba LABS, Cape Town, South Africa
| | - Thomas Ebenhan
- Nuclear Medicine Research Infrastructure NPC, Pretoria, South Africa
- Nuclear Medicine Department, University of Pretoria, Pretoria, South Africa
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Ruiz de Garibay G, García de Jalón E, Stigen E, Lund KB, Popa M, Davidson B, Safont MM, Rygh CB, Espedal H, Barrett TM, Haug BE, McCormack E. Repurposing 18F-FMISO as a PET tracer for translational imaging of nitroreductase-based gene directed enzyme prodrug therapy. Am J Cancer Res 2021; 11:6044-6057. [PMID: 33897898 PMCID: PMC8058731 DOI: 10.7150/thno.55092] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Accepted: 02/25/2021] [Indexed: 12/25/2022] Open
Abstract
Nitroreductases (NTR) are a family of bacterial enzymes used in gene directed enzyme prodrug therapy (GDEPT) that selectively activate prodrugs containing aromatic nitro groups to exert cytotoxic effects following gene transduction in tumours. The clinical development of NTR-based GDEPT has, in part, been hampered by the lack of translational imaging modalities to assess gene transduction and drug cytotoxicity, non-invasively. This study presents translational preclinical PET imaging to validate and report NTR activity using the clinically approved radiotracer, 18F-FMISO, as substrate for the NTR enzyme. Methods: The efficacy with which 18F-FMISO could be used to report NfsB NTR activity in vivo was investigated using the MDA-MB-231 mammary carcinoma xenograft model. For validation, subcutaneous xenografts of cells constitutively expressing NTR were imaged using 18F-FMISO PET/CT and fluorescence imaging with CytoCy5S, a validated fluorescent NTR substrate. Further, examination of the non-invasive functionality of 18F-FMISO PET/CT in reporting NfsB NTR activity in vivo was assessed in metastatic orthotopic NfsB NTR expressing xenografts and metastasis confirmed by bioluminescence imaging. 18F-FMISO biodistribution was acquired ex vivo by an automatic gamma counter measuring radiotracer retention to confirm in vivo results. To assess the functional imaging of NTR-based GDEPT with 18F-FMISO, PET/CT was performed to assess both gene transduction and cytotoxicity effects of prodrug therapy (CB1954) in subcutaneous models. Results:18F-FMISO retention was detected in NTR+ subcutaneous xenografts, displaying significantly higher PET contrast than NTR- xenografts (p < 0.0001). Substantial 18F-FMISO retention was evident in metastases of orthotopic xenografts (p < 0.05). Accordingly, higher 18F-FMISO biodistribution was prevalent ex vivo in NTR+ xenografts. 18F-FMISO NfsB NTR PET/CT imaging proved useful for monitoring in vivo NTR transduction and the cytotoxic effect of prodrug therapy. Conclusions:18F-FMISO NfsB NTR PET/CT imaging offered significant contrast between NTR+ and NTR- tumours and effective resolution of metastatic progression. Furthermore, 18F-FMISO NfsB NTR PET/CT imaging proved efficient in monitoring the two steps of GDEPT, in vivo NfsB NTR transduction and response to CB1954 prodrug therapy. These results support the repurposing of 18F-FMISO as a readily implementable PET imaging probe to be employed as companion diagnostic test for NTR-based GDEPT systems.
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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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Yang J, Sohn JH, Behr SC, Gullberg GT, Seo Y. CT-less Direct Correction of Attenuation and Scatter in the Image Space Using Deep Learning for Whole-Body FDG PET: Potential Benefits and Pitfalls. Radiol Artif Intell 2021; 3:e200137. [PMID: 33937860 PMCID: PMC8043359 DOI: 10.1148/ryai.2020200137] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 11/04/2020] [Accepted: 11/13/2020] [Indexed: 05/14/2023]
Abstract
PURPOSE To demonstrate the feasibility of CT-less attenuation and scatter correction (ASC) in the image space using deep learning for whole-body PET, with a focus on the potential benefits and pitfalls. MATERIALS AND METHODS In this retrospective study, 110 whole-body fluorodeoxyglucose (FDG) PET/CT studies acquired in 107 patients (mean age ± standard deviation, 58 years ± 18; age range, 11-92 years; 72 females) from February 2016 through January 2018 were randomly collected. A total of 37.3% (41 of 110) of the studies showed metastases, with diverse FDG PET findings throughout the whole body. A U-Net-based network was developed for directly transforming noncorrected PET (PETNC) into attenuation- and scatter-corrected PET (PETASC). Deep learning-corrected PET (PETDL) images were quantitatively evaluated by using the standardized uptake value (SUV) of the normalized root mean square error, the peak signal-to-noise ratio, and the structural similarity index, in addition to a joint histogram for statistical analysis. Qualitative reviews by radiologists revealed the potential benefits and pitfalls of this correction method. RESULTS The normalized root mean square error (0.21 ± 0.05 [mean SUV ± standard deviation]), mean peak signal-to-noise ratio (36.3 ± 3.0), mean structural similarity index (0.98 ± 0.01), and voxelwise correlation (97.62%) of PETDL demonstrated quantitatively high similarity with PETASC. Radiologist reviews revealed the overall quality of PETDL. The potential benefits of PETDL include a radiation dose reduction on follow-up scans and artifact removal in the regions with attenuation correction- and scatter correction-based artifacts. The pitfalls involve potential false-negative results due to blurring or missing lesions or false-positive results due to pseudo-low-uptake patterns. CONCLUSION Deep learning-based direct ASC at whole-body PET is feasible and potentially can be used to overcome the current limitations of CT-based approaches, benefiting patients who are sensitive to radiation from CT.Supplemental material is available for this article.© RSNA, 2020.
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Tago T, Toyohara J, Fujimaki R, Tatsuta M, Song R, Hirano K, Iwai K, Tanaka H. Effects of 18F-fluorinated neopentyl glycol side-chain on the biological characteristics of stilbene amyloid-β PET ligands. Nucl Med Biol 2021; 94-95:38-45. [PMID: 33493787 DOI: 10.1016/j.nucmedbio.2020.12.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 12/08/2020] [Accepted: 12/26/2020] [Indexed: 01/21/2023]
Abstract
INTRODUCTION The 2,2-dihydroxymethyl-1-[18F]fluoropropane group, also called 18F-labelled neopentyl glycol side-chain, is a novel 18F-labelling group for positron emission tomography (PET) imaging agents. The aim of using this group is to develop simple purification with solid-phase extraction without high-performance liquid chromatography. However, the effects of the neopentyl 18F-labelling group on the characteristics of brain imaging agents are unknown. Here, we added this side-chain to compounds with an aminostilbene structure to evaluate their effects on the biological properties of aminostilbene as an amyloid-β (Aβ) radioligand. METHODS Biodistributions of four novel 18F-labelled stilbene compounds with different lengths of polyethylene glycol (PEG) linkers, called [18F]Cpd-0, -1, -2, and -4, (PEG = 0, 1, 2, and 4), and [18F]AV-1 in normal mice were evaluated. Metabolite analysis of [18F]Cpd-0 and -1 was performed with mouse plasma and brain. A competitive binding assay of [18F]AV-1 binding to Aβ1-42 fibrils was performed to determine the binding properties of the compounds. RESULTS [18F]Cpd-0, -1, and -2 demonstrated moderate initial brain uptake in mice (3.1-4.2% injected dose/g at 2 min post-injection) followed by fast clearance, and in vivo defluorination of these compounds was negligible. [18F]Cpd-4 exhibited low brain uptake and high bone uptake. Compared with [18F]Cpd-1, the percentage of [18F]Cpd-0 in mouse brain was high at 10 min post-injection. A competitive binding assay revealed partial interference effects by the neopentyl glycol side-chain on binding of stilbene compounds to Aβ1-42 fibrils. CONCLUSIONS Aminostilbene compounds with two or fewer PEG linkers containing an 18F-labelled neopentyl glycol side-chain demonstrated preferable pharmacokinetic properties as a brain imaging radioligand in normal mice. These side-chains can be used as an alternative labelling group for imaging agents targeting the brain.
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Affiliation(s)
- Tetsuro Tago
- Research Team for Neuroimaging, Tokyo Metropolitan Institute of Gerontology, 35-2 Sakae-cho, Itabashi-ku, Tokyo 173-0015, Japan
| | - Jun Toyohara
- Research Team for Neuroimaging, Tokyo Metropolitan Institute of Gerontology, 35-2 Sakae-cho, Itabashi-ku, Tokyo 173-0015, Japan.
| | - Ryo Fujimaki
- Department of Chemical Science and Engineering, Tokyo Institute of Technology, Tokyo 152-8550, Japan
| | - Maho Tatsuta
- Department of Chemical Science and Engineering, Tokyo Institute of Technology, Tokyo 152-8550, Japan
| | - Ruichong Song
- Department of Chemical Science and Engineering, Tokyo Institute of Technology, Tokyo 152-8550, Japan
| | | | - Kumiko Iwai
- Department of Chemical Science and Engineering, Tokyo Institute of Technology, Tokyo 152-8550, Japan; NMP Business Support Co., Ltd., Hyogo 669-1339, Japan
| | - Hiroshi Tanaka
- Department of Chemical Science and Engineering, Tokyo Institute of Technology, Tokyo 152-8550, Japan
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Abstract
Over the last few years, cancer immunotherapy experienced tremendous developments and it is nowadays considered a promising strategy against many types of cancer. However, the exclusion of lymphocytes from the tumor nest is a common phenomenon that limits the efficiency of immunotherapy in solid tumors. Despite several mechanisms proposed during the years to explain the immune excluded phenotype, at present, there is no integrated understanding about the role played by different models of immune exclusion in human cancers. Hypoxia is a hallmark of most solid tumors and, being a multifaceted and complex condition, shapes in a unique way the tumor microenvironment, affecting gene transcription and chromatin remodeling. In this review, we speculate about an upstream role for hypoxia as a common biological determinant of immune exclusion in solid tumors. We also discuss the current state of ex vivo and in vivo imaging of hypoxic determinants in relation to T cell distribution that could mechanisms of immune exclusion and discover functional-morphological tumor features that could support clinical monitoring.
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Watanabe S, Nishijima KI, Okamoto S, Magota K, Hirata K, Toyonaga T, Shiga T, Kuge Y, Tamaki N. Biodistribution and internal radiation dosimetry of a novel probe for thymidine phosphorylase imaging, [ 123I]IIMU, in healthy volunteers. Ann Nucl Med 2020; 34:595-599. [PMID: 32361818 DOI: 10.1007/s12149-020-01469-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Accepted: 04/21/2020] [Indexed: 11/25/2022]
Abstract
OBJECTIVE We evaluated the radiation dosage, biodistribution, human safety, and tolerability of the injection of a single dose of [123I] 5-iodo-6-[(2-iminoimidazolidinyl)methyl]uracil (IIMU), a new radiotracer targeting thymidine phosphorylase (TP), in healthy volunteers. METHODS Potential participants were tested at our hospital to confirm their eligibility. Two healthy male adults passed the screening tests. They were injected with 56 and 111 MBq of [123I]IIMU, respectively. Safety assessments were performed before and at 1, 3, 6, 9, 24, 48 h, and 1-week post-injection. Whole-body emission scans were conducted at 1, 3, 6, 24, and 48 h post-injection. Regions of interest were manually drawn to enclose the entire body at each time point, identifying high-uptake organs to obtain the time-activity curves. Urine and blood samples were collected at 1, 2, 3, 4, 5, 6, 9, 24, and 48 h post-injection. The radiation dose for each organ and the effective doses were estimated using OLINDA/EXM 1.1 software. RESULTS No adverse events were observed as of the follow-up visit > 1-week post-injection. In both subjects, the highest uptake of [123I]IIMU occurred in the liver, with peak injected activity (%IA) values of 17.7% and 15.1%, respectively. The second highest uptake was in the thyroid (0.35% and 0.66% IA). The %IA decreased gradually toward the end of the study (48 h) in all organs except the liver and thyroid. By the end of the study, 52.5% and 51.5% of the injected activity of [123I]IIMU had been excreted via the subjects' renal systems. The estimated mean effective doses of [123I]IIMU were 9.19 μSv/MBq and 10.1 μSv/MBq, respectively. CONCLUSION In this preliminary study, [123I]IIMU was safely administered to healthy adults, and its potential clinical use in TP imaging was revealed.
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Affiliation(s)
- Shiro Watanabe
- Department of Nuclear Medicine, Hokkaido University Graduate School of Medicine, Kita-15, Nishi-7, Kita-ku, Sapporo, 060-8638, Japan. .,Department of Diagnostic Radiology, Hokkaido Cancer Center, 3-54, Kikusui4-2, Shiroishi-ku, Sapporo, 003-0804, Japan.
| | - Ken-Ichi Nishijima
- Central Institute of Isotope Science, Hokkaido University, Kita-15, Nishi-7, Kita-ku, Sapporo, 060-8638, Japan.,Advanced Clinical Research Center, Fukushima Global Medical Science Center, Fukushima Medical University, 1 Hikariga-oka, Fukushima, 960-1295, Japan
| | - Shozo Okamoto
- Department of Nuclear Medicine, Hokkaido University Graduate School of Medicine, Kita-15, Nishi-7, Kita-ku, Sapporo, 060-8638, Japan.,Department of Radiology, Obihiro Kosei Hospital, West 14, South 10-1, Obihiro, 080-0024, Japan
| | - Keiichi Magota
- Division of Medical Imaging and Technology, Hokkaido University Hospital, Kita-14, Nishi-5, Kita-ku, Sapporo, 060-8648, Japan
| | - Kenji Hirata
- Department of Nuclear Medicine, Hokkaido University Graduate School of Medicine, Kita-15, Nishi-7, Kita-ku, Sapporo, 060-8638, Japan.,Department of Diagnostic Imaging, Hokkaido University Graduate School of Medicine, Kita-15, Nishi-7, Kita-ku, Sapporo, 060-8638, Japan
| | - Takuya Toyonaga
- Department of Nuclear Medicine, Hokkaido University Graduate School of Medicine, Kita-15, Nishi-7, Kita-ku, Sapporo, 060-8638, Japan.,PET Center, Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, CT, 06520, USA
| | - Tohru Shiga
- Department of Nuclear Medicine, Hokkaido University Graduate School of Medicine, Kita-15, Nishi-7, Kita-ku, Sapporo, 060-8638, Japan
| | - Yuji Kuge
- Central Institute of Isotope Science, Hokkaido University, Kita-15, Nishi-7, Kita-ku, Sapporo, 060-8638, Japan
| | - Nagara Tamaki
- Department of Nuclear Medicine, Hokkaido University Graduate School of Medicine, Kita-15, Nishi-7, Kita-ku, Sapporo, 060-8638, Japan.,Department of Radiology, Kyoto Prefectural University of Medicine, Kajii-cho, Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto, 602-8566, Japan
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13
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Hypoxia PET imaging beyond 18F-FMISO in patients with high-grade glioma: 18F-FAZA and other hypoxia radiotracers. Clin Transl Imaging 2020. [DOI: 10.1007/s40336-020-00358-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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14
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Drake LR, Hillmer AT, Cai Z. Approaches to PET Imaging of Glioblastoma. Molecules 2020; 25:E568. [PMID: 32012954 PMCID: PMC7037643 DOI: 10.3390/molecules25030568] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 01/22/2020] [Accepted: 01/23/2020] [Indexed: 12/15/2022] Open
Abstract
Glioblastoma multiforme (GBM) is the deadliest type of brain tumor, affecting approximately three in 100,000 adults annually. Positron emission tomography (PET) imaging provides an important non-invasive method of measuring biochemically specific targets at GBM lesions. These powerful data can characterize tumors, predict treatment effectiveness, and monitor treatment. This review will discuss the PET imaging agents that have already been evaluated in GBM patients so far, and new imaging targets with promise for future use. Previously used PET imaging agents include the tracers for markers of proliferation ([11C]methionine; [18F]fluoro-ethyl-L-tyrosine, [18F]Fluorodopa,[18F]fluoro-thymidine, and [18F]clofarabine), hypoxia sensing ([18F]FMISO, [18F]FET-NIM, [18F]EF5, [18F]HX4, and [64Cu]ATSM), and ligands for inflammation. As cancer therapeutics evolve toward personalized medicine and therapies centered on tumor biomarkers, the development of complimentary selective PET agents can dramatically enhance these efforts. Newer biomarkers for GBM PET imaging are discussed, with some already in use for PET imaging other cancers and neurological disorders. These targets include Sigma 1, Sigma 2, programmed death ligand 1, poly-ADP-ribose polymerase, and isocitrate dehydrogenase. For GBM, these imaging agents come with additional considerations such as blood-brain barrier penetration, quantitative modeling approaches, and nonspecific binding.
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Affiliation(s)
- Lindsey R. Drake
- Yale PET Center, Yale University School of Medicine, New Haven, CT 06511, USA; (A.T.H.); (Z.C.)
- Department of Radiology and Bioimaging Sciences, Yale University School of Medicine, New Haven, CT 06511, USA
| | - Ansel T. Hillmer
- Yale PET Center, Yale University School of Medicine, New Haven, CT 06511, USA; (A.T.H.); (Z.C.)
- Department of Radiology and Bioimaging Sciences, Yale University School of Medicine, New Haven, CT 06511, USA
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT 06511, USA
- Department of Biomedical Engineering, Yale School of Engineering and Applied Science, New Haven, CT 06511, USA
| | - Zhengxin Cai
- Yale PET Center, Yale University School of Medicine, New Haven, CT 06511, USA; (A.T.H.); (Z.C.)
- Department of Radiology and Bioimaging Sciences, Yale University School of Medicine, New Haven, CT 06511, USA
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15
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Kobayashi K, Manabe O, Hirata K, Yamaguchi S, Kobayashi H, Terasaka S, Toyonaga T, Furuya S, Magota K, Kuge Y, Kudo K, Shiga T, Tamaki N. Influence of the scan time point when assessing hypoxia in 18F-fluoromisonidazole PET: 2 vs. 4 h. Eur J Nucl Med Mol Imaging 2019; 47:1833-1842. [PMID: 31781832 DOI: 10.1007/s00259-019-04626-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Accepted: 11/18/2019] [Indexed: 11/28/2022]
Abstract
PURPOSE 18F-fluoromisonidazole (18F-FMISO) is the most widely used positron emission tomography (PET) tracer for imaging tumor hypoxia. Previous reports suggested that the time from injection to the scan may affect the assessment of 18F-FMISO uptake. Herein, we directly compared the images at 2 h and 4 h after a single injection of 18F-FMISO. METHODS Twenty-three patients with or suspected of having a brain tumor were scanned twice at 2 and 4 h following an intravenous injection of 18F-FMISO. We estimated the mean standardized uptake value (SUV) of the gray matter and white matter and the gray-to-white matter ratio in the background brain tissue from the two scans. We also performed a semi-quantitative analysis using the SUVmax and maximum tumor-to-normal ratio (TNR) for the tumor. RESULTS At 2 h, the SUVmean of gray matter was significantly higher than that of white matter (median 1.23, interquartile range (IQR) 1.10-1.32 vs. 1.04, IQR 0.95-1.16, p < 0.0001), whereas at 4 h, it significantly decreased to approach that of the white matter (1.10, IQR 1.00-1.23 vs. 1.02, IQR 0.93-1.13, p = NS). The gray-to-white matter ratio thus significantly declined from 1.17 (IQR 1.14-1.19) to 1.09 (IQR 1.07-1.10) (p < 0.0001). All 7 patients with glioblastoma showed significant increases in the SUVmax (2.20, IQR 1.67-3.32 at 2 h vs. 2.65, IQR 1.74-4.41 at 4 h, p = 0.016) and the TNR (1.75, IQR 1.40-2.38 at 2 h vs. 2.34, IQR 1.67-3.60 at 4 h, p = 0.016). CONCLUSION In the assessment of hypoxic tumors, 18F-FMISO PET for hypoxia imaging should be obtained at 4 h rather than 2 h after the injection.
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Affiliation(s)
- Kentaro Kobayashi
- Department of Diagnostic and Interventional Radiology, Hokkaido University Hospital, Sapporo, Hokkaido, 060-8638, Japan
| | - Osamu Manabe
- Department of Diagnostic and Interventional Radiology, Hokkaido University Hospital, Sapporo, Hokkaido, 060-8638, Japan
| | - Kenji Hirata
- Department of Diagnostic and Interventional Radiology, Hokkaido University Hospital, Sapporo, Hokkaido, 060-8638, Japan.
| | - Shigeru Yamaguchi
- Department of Neurosurgery, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | | | | | - Takuya Toyonaga
- Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, CT, USA
| | - Sho Furuya
- Department of Diagnostic and Interventional Radiology, Hokkaido University Hospital, Sapporo, Hokkaido, 060-8638, Japan
| | - Keiichi Magota
- Division of Medical Imaging and Technology, Hokkaido University Hospital, Sapporo, Japan
| | - Yuji Kuge
- Central Institute of Isotope Science, Hokkaido University, Sapporo, Japan
| | - Kohsuke Kudo
- Department of Diagnostic Imaging, Hokkaido University Graduate School of Medicine, Sapporo, Japan.,Global Station for Quantum Medical Science and Engineering, Global Institution for Collaborative Research and Education, Hokkaido University, Sapporo, Japan
| | - Tohru Shiga
- Department of Diagnostic and Interventional Radiology, Hokkaido University Hospital, Sapporo, Hokkaido, 060-8638, Japan
| | - Nagara Tamaki
- Department of Radiology, Kyoto Prefectural University, Kyoto, Japan
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16
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The Roles of Hypoxia Imaging Using 18F-Fluoromisonidazole Positron Emission Tomography in Glioma Treatment. J Clin Med 2019; 8:jcm8081088. [PMID: 31344848 PMCID: PMC6723061 DOI: 10.3390/jcm8081088] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2019] [Revised: 07/16/2019] [Accepted: 07/22/2019] [Indexed: 12/14/2022] Open
Abstract
Glioma is the most common malignant brain tumor. Hypoxia is closely related to the malignancy of gliomas, and positron emission tomography (PET) can noninvasively visualize the degree and the expansion of hypoxia. Currently, 18F-fluoromisonidazole (FMISO) is the most common radiotracer for hypoxia imaging. The clinical usefulness of FMISO PET has been established; it can distinguish glioblastomas from lower-grade gliomas and can predict the microenvironment of a tumor, including necrosis, vascularization, and permeability. FMISO PET provides prognostic information, including survival and treatment response information. Because hypoxia decreases a tumor’s sensitivity to radiation therapy, dose escalation to an FMISO-positive volume is an attractive strategy. Although this idea is not new, an insufficient amount of evidence has been obtained regarding this concept. New tracers for hypoxia imaging such as 18F-DiFA are being tested. In the future, hypoxia imaging will play an important role in glioma management.
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