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Saha E, Shimochi S, Keller T, Eskola O, López-Picón F, Rajander J, Löyttyniemi E, Forsback S, Solin O, Grönroos TJ, Parikka V. Evaluation of PET imaging as a tool for detecting neonatal hypoxic-ischemic encephalopathy in a preclinical animal model. Exp Neurol 2024; 373:114673. [PMID: 38163475 DOI: 10.1016/j.expneurol.2023.114673] [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: 09/13/2023] [Revised: 12/09/2023] [Accepted: 12/29/2023] [Indexed: 01/03/2024]
Abstract
Hypoxic-ischemic encephalopathy due to insufficient oxygen delivery to brain tissue is a leading cause of death or severe morbidity in neonates. The early recognition of the most severely affected individuals remains a clinical challenge. We hypothesized that hypoxic-ischemic injury can be detected using PET radiotracers for hypoxia ([18F]EF5), glucose metabolism ([18F]FDG), and inflammation ([18F]F-DPA). METHODS A preclinical model of neonatal hypoxic-ischemic brain injury was made in 9-d-old rat pups by permanent ligation of the left common carotid artery followed by hypoxia (8% oxygen and 92% nitrogen) for 120 min. In vivo PET imaging was performed immediately after injury induction or at different timepoints up to 21 d later. After imaging, ex vivo brain autoradiography was performed. Brain sections were stained with cresyl violet to evaluate the extent of the brain injury and to correlate it with [18F]FDG uptake. RESULTS PET imaging revealed that all three of the radiotracers tested had significant uptake in the injured brain hemisphere. Ex vivo autoradiography revealed high [18F]EF5 uptake in the hypoxic hemisphere immediately after the injury (P < 0.0001), decreasing to baseline even 1 d postinjury. [18F]FDG uptake was highest in the injured hemisphere on the day of injury (P < 0.0001), whereas [18F]F-DPA uptake was evident after 4 d (P = 0.029), peaking 7 d postinjury (P < 0.0001), and remained significant 21 d after the injury. Targeted evaluation demonstrated that [18F]FDG uptake measured by in vivo imaging 1 d postinjury correlated positively with the brain volume loss detected 21 d later (r = 0.72, P = 0.028). CONCLUSION Neonatal hypoxic-ischemic brain injury can be detected using PET imaging. Different types of radiotracers illustrate distinct phases of hypoxic brain damage. PET may be a new useful technique, worthy of being explored for clinical use, to predict and evaluate the course of the injury.
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Affiliation(s)
- Emma Saha
- Preclinical Imaging Laboratory, Turku PET Centre, University of Turku, Turku, Finland; MediCity Research Laboratories, University of Turku, Turku, Finland; Department of Pediatrics and Adolescent Medicine, Turku University Hospital, Turku, Finland.
| | - Saeka Shimochi
- Preclinical Imaging Laboratory, Turku PET Centre, University of Turku, Turku, Finland; MediCity Research Laboratories, University of Turku, Turku, Finland
| | - Thomas Keller
- Radiopharmaceutical Chemistry Laboratory, Turku PET Centre, University of Turku, Turku, Finland
| | - Olli Eskola
- Radiopharmaceutical Chemistry Laboratory, Turku PET Centre, University of Turku, Turku, Finland
| | - Francisco López-Picón
- Preclinical Imaging Laboratory, Turku PET Centre, University of Turku, Turku, Finland; MediCity Research Laboratories, University of Turku, Turku, Finland
| | - Johan Rajander
- Accelerator Laboratory, Turku PET Centre, Åbo Akademi University, Turku, Finland
| | | | - Sarita Forsback
- Radiopharmaceutical Chemistry Laboratory, Turku PET Centre, University of Turku, Turku, Finland
| | - Olof Solin
- Radiopharmaceutical Chemistry Laboratory, Turku PET Centre, University of Turku, Turku, Finland; Accelerator Laboratory, Turku PET Centre, Åbo Akademi University, Turku, Finland; Department of Chemistry, University of Turku, Finland
| | - Tove J Grönroos
- Preclinical Imaging Laboratory, Turku PET Centre, University of Turku, Turku, Finland; MediCity Research Laboratories, University of Turku, Turku, Finland
| | - Vilhelmiina Parikka
- Preclinical Imaging Laboratory, Turku PET Centre, University of Turku, Turku, Finland; MediCity Research Laboratories, University of Turku, Turku, Finland; Department of Pediatrics and Adolescent Medicine, Turku University Hospital, Turku, Finland; InFLAMES Research Flagship Center, University of Turku, Turku, Finland
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Dos Santos SN, Wuest M, Jans HS, Woodfield J, Nario AP, Krys D, Dufour J, Glubrecht D, Bergman C, Bernardes ES, Wuest F. Comparison of three 18F-labeled 2-nitroimidazoles for imaging hypoxia in breast cancer xenografts: [ 18F]FBNA, [ 18F]FAZA and [ 18F]FMISO. Nucl Med Biol 2023; 124-125:108383. [PMID: 37651917 DOI: 10.1016/j.nucmedbio.2023.108383] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 08/24/2023] [Accepted: 08/25/2023] [Indexed: 09/02/2023]
Abstract
BACKGROUND Tumour hypoxia is associated with increased metastasis, invasion, poor therapy response and prognosis. Most PET radiotracers developed and used for clinical hypoxia imaging belong to the 2-nitroimidazole family. Recently we have developed novel 2-nitroimidazole-derived PET radiotracer [18F]FBNA (N-(4-[18F]fluoro-benzyl)-2-(2-nitro-1H-imidazol-1-yl)-acet-amide), an 18F-labeled analogue of antiparasitic drug benznidazole. The present study aimed to analyze its radio-pharmacological properties and systematically compare its PET imaging profiles with [18F]FMISO and [18F]FAZA in preclinical triple-negative (MDA-MB231) and estrogen receptor-positive (MCF-7) breast cancer models. METHODS In vitro cellular uptake experiments were carried out in MDA-MB321 and MCF-7 cells under normoxic and hypoxic conditions. Metabolic stability in vivo was determined in BALB/c mice using radio-TLC analysis. Dynamic PET experiments over 3 h post-injection were performed in MDA-MB231 and MCF-7 tumour-bearing mice. Those PET data were used for kinetic modelling analysis utilizing the reversible two-tissue-compartment model. Autoradiography was carried out in tumour tissue slices and compared to HIF-1α immunohistochemistry. Detailed ex vivo biodistribution was accomplished in BALB/c mice, and this biodistribution data were used for dosimetry calculation. RESULTS Under hypoxic conditions in vitro cellular uptake was elevated in both cell lines, MCF-7 and MDA-MB231, for all three radiotracers. After intravenous injection, [18F]FBNA formed two radiometabolites, resulting in a final fraction of 65 ± 9 % intact [18F]FBNA after 60 min p.i. After 3 h p.i., [18F]FBNA tumour uptake reached SUV values of 0.78 ± 0.01 in MCF-7 and 0.61 ± 0.04 in MDA-MB231 tumours (both n = 3), representing tumour-to-muscle ratios of 2.19 ± 0.04 and 1.98 ± 0.15, respectively. [18F]FMISO resulted in higher tumour uptakes (SUV 1.36 ± 0.04 in MCF-7 and 1.23 ± 0.08 in MDA-MB231 (both n = 4; p < 0.05) than [18F]FAZA (0.66 ± 0.11 in MCF-7 and 0.63 ± 0.14 in MDA-MB231 (both n = 4; n.s.)), representing tumour-to-muscle ratios of 3.24 ± 0.30 and 3.32 ± 0.50 for [18F]FMISO, and 2.92 ± 0.74 and 3.00 ± 0.42 for [18F]FAZA, respectively. While the fraction per time of radiotracer entering the second compartment (k3) was similar within uncertainties for all three radiotracers in MDA-MB231 tumours, it was different in MCF-7 tumours. The ratios k3/(k3 + k2) and K1*k3/(k3 + k2) in MCF-7 tumours were also significantly different, indicating dissimilar fractions of radiotracer bound and trapped intracellularly: K1*k3/(k2 + k3) [18F]FMISO (0.0088 ± 0.001)/min, n = 4; p < 0.001) > [18F]FAZA (0.0052 ± 0.002)/min, n = 4; p < 0.01) > [18F]FBNA (0.003 ± 0.001)/min, n = 3). In contrast, in MDA-MB231 tumours, only K1 was significantly elevated for [18F]FMISO. However, this did not result in significant differences for K1*k3/(k2 + k3) for all three 2-nitroimidazoles in MDA-MB231 tumours. CONCLUSION Novel 2-nitroimidazole PET radiotracer [18F]FBNA showed uptake into hypoxic breast cancer cells and tumour tissue presumably associated with elevated HIF1-α expression. Systematic comparison of PET imaging performance with [18F]FMISO and [18F]FAZA in different types of preclinical breast cancer models revealed a similar tumour uptake profile for [18F]FBNA with [18F]FAZA and, despite its higher lipophilicity, still a slightly higher muscle tissue clearance compared to [18F]FMISO.
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Affiliation(s)
- Sofia Nascimento Dos Santos
- Radiopharmacy Center, Nuclear and Energy Research Institute (IPEN / CNEN - SP), CEP 05508-000 São Paulo, SP, Brazil
| | - Melinda Wuest
- Department of Oncology, University of Alberta, Cross Cancer Institute, Edmonton T6G 2R7, Alberta, Canada
| | - Hans-Sonke Jans
- Department of Oncology, University of Alberta, Cross Cancer Institute, Edmonton T6G 2R7, Alberta, Canada
| | - Jenilee Woodfield
- Department of Oncology, University of Alberta, Cross Cancer Institute, Edmonton T6G 2R7, Alberta, Canada
| | - Arian Pérez Nario
- Radiopharmacy Center, Nuclear and Energy Research Institute (IPEN / CNEN - SP), CEP 05508-000 São Paulo, SP, Brazil
| | - Daniel Krys
- Department of Oncology, University of Alberta, Cross Cancer Institute, Edmonton T6G 2R7, Alberta, Canada
| | - Jennifer Dufour
- Department of Oncology, University of Alberta, Cross Cancer Institute, Edmonton T6G 2R7, Alberta, Canada
| | - Darryl Glubrecht
- Department of Oncology, University of Alberta, Cross Cancer Institute, Edmonton T6G 2R7, Alberta, Canada
| | - Cody Bergman
- Department of Oncology, University of Alberta, Cross Cancer Institute, Edmonton T6G 2R7, Alberta, Canada
| | - Emerson Soares Bernardes
- Radiopharmacy Center, Nuclear and Energy Research Institute (IPEN / CNEN - SP), CEP 05508-000 São Paulo, SP, Brazil
| | - Frank Wuest
- Department of Oncology, University of Alberta, Cross Cancer Institute, Edmonton T6G 2R7, Alberta, Canada.
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Narva SI, Seppänen MP, Raiko JRH, Forsback SJ, Orte KJ, Virtanen JM, Hynninen J, Hietanen S. Imaging of Tumor Hypoxia With 18F-EF5 PET/MRI in Cervical Cancer. Clin Nucl Med 2021; 46:952-957. [PMID: 34619699 DOI: 10.1097/rlu.0000000000003914] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
PURPOSE OF THE REPORT The aim of this study was to evaluate the distribution of hypoxia using 18F-EF5 as a hypoxia tracer in cervical cancer patients with PET/MRI. We investigated the association between this 18F-EF5-PET tracer and the immunohistochemical expression of endogenous hypoxia markers: HIF1α, CAIX, and GLUT1. PATIENTS AND METHODS Nine patients with biopsy-proven primary squamous cell cervix carcinoma (FIGO 2018 radiological stages IB1-IIIC2r) were imaged with dual tracers 18F-EF5 and 18F-FDG using PET/MRI (Int J Gynaecol Obstet. 2019;145:129-135). 18F-EF5 images were analyzed by calculating the tumor-to-muscle ratio to determine the hypoxic tissue (T/M ratio >1.5) and further hypoxic subvolume (HSV) and percentage hypoxic area. These 18F-EF5 hypoxic parameters were correlated with the size and localization of tumors in 18F-FDG PET/MRI and the results of hypoxia immunohistochemistry. RESULTS All primary tumors were clearly 18F-FDG and 18F-EF5 PET positive and heterogeneously hypoxic with multiple 18F-EF5-avid areas in locally advanced cancer and single areas in clinically stage I tumors. The location of hypoxia was detected mainly in the periphery of tumor. Hypoxia parameters 18F-EF5 max T/M ratio and HSV in primary tumors correlated independently with the advanced stage (P = 0.036 and P = 0.040, respectively), and HSV correlated with the tumor size (P = 0.027). The location of hypoxia in 18F-EF5 imaging was confirmed with a higher hypoxic marker expression HIF1α and CAIX in tumor fresh biopsies. CONCLUSIONS The 18F-EF5 imaging has promising potential in detecting areas of tumor hypoxia in cervical cancer.
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Ajenjo J, Destro G, Cornelissen B, Gouverneur V. Closing the gap between 19F and 18F chemistry. EJNMMI Radiopharm Chem 2021; 6:33. [PMID: 34564781 PMCID: PMC8464544 DOI: 10.1186/s41181-021-00143-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Accepted: 08/03/2021] [Indexed: 11/10/2022] Open
Abstract
Positron emission tomography (PET) has become an invaluable tool for drug discovery and diagnosis. The positron-emitting radionuclide fluorine-18 is frequently used in PET radiopharmaceuticals due to its advantageous characteristics; hence, methods streamlining access to 18F-labelled radiotracers can make a direct impact in medicine. For many years, access to 18F-labelled radiotracers was limited by the paucity of methodologies available, and the poor diversity of precursors amenable to 18F-incorporation. During the last two decades, 18F-radiochemistry has progressed at a fast pace with the appearance of numerous methodologies for late-stage 18F-incorporation onto complex molecules from a range of readily available precursors including those that do not require pre-functionalisation. Key to these advances is the inclusion of new activation modes to facilitate 18F-incorporation. Specifically, new advances in late-stage 19F-fluorination under transition metal catalysis, photoredox catalysis, and organocatalysis combined with the availability of novel 18F-labelled fluorination reagents have enabled the invention of novel processes for 18F-incorporation onto complex (bio)molecules. This review describes these major breakthroughs with a focus on methodologies for C-18F bond formation. This reinvigorated interest in 18F-radiochemistry that we have witnessed in recent years has made a direct impact on 19F-chemistry with many laboratories refocusing their efforts on the development of methods using nucleophilic fluoride instead of fluorination reagents derived from molecular fluorine gas.
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Affiliation(s)
- Javier Ajenjo
- Medical Research Council Oxford Institute for Radiation Oncology, University of Oxford, Oxford, OX3 7DQ, UK
| | - Gianluca Destro
- Medical Research Council Oxford Institute for Radiation Oncology, University of Oxford, Oxford, OX3 7DQ, UK
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford, OX1 3TA, UK
| | - Bart Cornelissen
- Medical Research Council Oxford Institute for Radiation Oncology, University of Oxford, Oxford, OX3 7DQ, UK
| | - Véronique Gouverneur
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford, OX1 3TA, UK.
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The feasibility of [ 18F]EF5-PET/CT to image hypoxia in ovarian tumors: a clinical study. EJNMMI Res 2020; 10:103. [PMID: 32910291 PMCID: PMC7483702 DOI: 10.1186/s13550-020-00689-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Accepted: 08/13/2020] [Indexed: 12/14/2022] Open
Abstract
Rationale Evaluation of the feasibility of [18F]EF5-PET/CT scan in identifying hypoxic lesions in ovarian tumors in prospective clinical setting. Methods Fifteen patients with a suspected malignant ovarian tumor were scanned with [18F]EF5 and [18F]FDG-PET/CT preoperatively. The distribution of [18F]EF5-uptake, total intraabdominal metabolic tumor volume (TMTV), and hypoxic subvolume (HSV) were assessed. Results [18F]EF5-PET/CT suggested hypoxia in 47% (7/15) patients. The median HSV was 87 cm3 (31% of TMTV). The [18F]EF5-uptake was detected in primary tumors and in four patients also in intra-abdominal metastases. The [18F]EF5-uptake in cancer tissue was low compared to physiological excretory pathways, complicating the interpretation of PET/CT images. Conclusions [18F]EF5-PET/CT is not feasible in ovarian cancer imaging in clinical setting due to physiological intra-abdominal [18F]EF5-accumulation. However, it may be useful when used complementarily to FDG-PET/CT.
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Ermert J, Benešová M, Hugenberg V, Gupta V, Spahn I, Pietzsch HJ, Liolios C, Kopka K. Radiopharmaceutical Sciences. Clin Nucl Med 2020. [DOI: 10.1007/978-3-030-39457-8_2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Silvoniemi A, Suilamo S, Laitinen T, Forsback S, Löyttyniemi E, Vaittinen S, Saunavaara V, Solin O, Grönroos TJ, Minn H. Repeatability of tumour hypoxia imaging using [ 18F]EF5 PET/CT in head and neck cancer. Eur J Nucl Med Mol Imaging 2017; 45:161-169. [PMID: 29075831 PMCID: PMC5745570 DOI: 10.1007/s00259-017-3857-3] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Accepted: 10/09/2017] [Indexed: 11/30/2022]
Abstract
Purpose Hypoxia contributes to radiotherapy resistance and more aggressive behaviour of several types of cancer. This study was designed to evaluate the repeatability of intratumour uptake of the hypoxia tracer [18F]EF5 in paired PET/CT scans. Methods Ten patients with newly diagnosed head and neck cancer (HNC) received three static PET/CT scans before chemoradiotherapy: two with [18F]EF5 a median of 7 days apart and one with [18F]FDG. Metabolically active primary tumour volumes were defined in [18F]FDG images and transferred to co-registered [18F]EF5 images for repeatability analysis. A tumour-to-muscle uptake ratio (TMR) of 1.5 at 3 h from injection of [18F]EF5 was used as a threshold representing hypoxic tissue. Results In 10 paired [18F]EF5 PET/CT image sets, SUVmean, SUVmax, and TMR showed a good correlation with the intraclass correlation coefficients of 0.81, 0.85, and 0.87, respectively. The relative coefficients of repeatability for these parameters were 15%, 17%, and 10%, respectively. Fractional hypoxic volumes of the tumours in the repeated scans had a high correlation using the Spearman rank correlation test (r = 0.94). In a voxel-by-voxel TMR analysis between the repeated scans, the mean of Pearson correlation coefficients of individual patients was 0.65. The mean (± SD) difference of TMR in the pooled data set was 0.03 ± 0.20. Conclusion Pretreatment [18F]EF5 PET/CT within one week shows high repeatability and is feasible for the guiding of hypoxia-targeted treatment interventions in HNC.
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Affiliation(s)
- Antti Silvoniemi
- Turku PET Centre, University of Turku, P.O. BOX 52, FI-20521, Turku, Finland. .,Department of Otorhinolaryngology - Head and Neck Surgery, Turku University Hospital, P.O. BOX 52, FI-20521, Turku, Finland.
| | - Sami Suilamo
- Department of Oncology and Radiotherapy, Turku University Hospital, P.O. BOX 52, FI-20521, Turku, Finland.,Department of Medical Physics, Turku University Hospital, P.O. BOX 52, FI-20521, Turku, Finland
| | - Timo Laitinen
- Turku PET Centre, University of Turku, P.O. BOX 52, FI-20521, Turku, Finland
| | - Sarita Forsback
- Turku PET Centre, University of Turku, P.O. BOX 52, FI-20521, Turku, Finland
| | | | - Samuli Vaittinen
- Department of Pathology, Turku University Hospital, P.O. BOX 52, FI-20521, Turku, Finland
| | - Virva Saunavaara
- Turku PET Centre, University of Turku, P.O. BOX 52, FI-20521, Turku, Finland.,Department of Medical Physics, Turku University Hospital, P.O. BOX 52, FI-20521, Turku, Finland
| | - Olof Solin
- Turku PET Centre, University of Turku, P.O. BOX 52, FI-20521, Turku, Finland
| | - Tove J Grönroos
- Turku PET Centre, University of Turku, P.O. BOX 52, FI-20521, Turku, Finland.,Department of Oncology and Radiotherapy, Turku University Hospital, P.O. BOX 52, FI-20521, Turku, Finland
| | - Heikki Minn
- Turku PET Centre, University of Turku, P.O. BOX 52, FI-20521, Turku, Finland.,Department of Oncology and Radiotherapy, Turku University Hospital, P.O. BOX 52, FI-20521, Turku, Finland
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Chitneni SK, Bida GT, Zalutsky MR, Dewhirst MW. Reply: Pharmacokinetic and Pharmacodynamic Modifiers of EF5 Uptake and Binding. J Nucl Med 2015; 56:653-4. [PMID: 25745087 DOI: 10.2967/jnumed.115.154054] [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] Open
Affiliation(s)
| | - Gerald T Bida
- Duke University Medical Center Box 3808Durham, NC 27710 E-mail:
| | | | - Mark W Dewhirst
- Duke University Medical Center Box 3808Durham, NC 27710 E-mail:
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Silvoniemi A, Silén J, Forsback S, Löyttyniemi E, Schrey AR, Solin O, Grénman R, Minn H, Grönroos TJ. Evaluation of repeated [(18)F]EF5 PET/CT scans and tumor growth rate in experimental head and neck carcinomas. EJNMMI Res 2014; 4:65. [PMID: 25977879 PMCID: PMC4412195 DOI: 10.1186/s13550-014-0065-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Accepted: 11/11/2014] [Indexed: 01/07/2023] Open
Abstract
Background Tumor hypoxia is linked to invasion and metastasis but whether this associates with tumor growth rate is not well understood. We aimed to study the relationship between hypoxia evaluated with the positron emission tomography (PET) tracer [18F]EF5 and tumor growth. Our second goal was to assess the variability in the uptake of [18F]EF5 in tumor between two scans. Methods Four human head and neck squamous cell carcinoma (UT-SCC) cell lines were xenografted in flank or neck of nude mice, and tumor size was closely monitored over the study period. The tumors were clearly visible when the first [18F]EF5 scan was acquired. After an exponential growth phase, the tumors were imaged again with [18F]EF5 and also with 18F-fluorodeoxyglucose ([18F]FDG). Results There was a clear correlation between the percentage of tumor growth rate per day and the [18F]EF5 uptake in the latter scan (r = 0.766, p = 0.01). The uptake of [18F]EF5 in the first scan and the uptake of [18F]FDG did not significantly correlate with the tumor growth rate. We also observed considerable variations in the uptake of [18F]EF5 between the two scans. Conclusions The uptake of [18F]EF5 in the late phase of exponential tumor growth is associated with the tumor growth rate in mice bearing HNC xenografts.
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Affiliation(s)
- Antti Silvoniemi
- Turku PET Centre, Medicity Research Laboratory, University of Turku, Tykistökatu 6A, Turku, FI-20520, Finland ; Department of Otorhinolaryngology - Head and Neck Surgery, Turku University Hospital, Turku, FI-20521, Finland
| | - Jonna Silén
- Turku PET Centre, Medicity Research Laboratory, University of Turku, Tykistökatu 6A, Turku, FI-20520, Finland
| | - Sarita Forsback
- Turku PET Centre, Medicity Research Laboratory, University of Turku, Tykistökatu 6A, Turku, FI-20520, Finland
| | - Eliisa Löyttyniemi
- Department of Biostatistics, University of Turku, Lemminkäisenkatu 1, Turku, FI-20520, Finland
| | - Aleksi R Schrey
- Department of Otorhinolaryngology - Head and Neck Surgery, Turku University Hospital, Turku, FI-20521, Finland
| | - Olof Solin
- Turku PET Centre, Medicity Research Laboratory, University of Turku, Tykistökatu 6A, Turku, FI-20520, Finland
| | - Reidar Grénman
- Department of Otorhinolaryngology - Head and Neck Surgery, Turku University Hospital, Turku, FI-20521, Finland
| | - Heikki Minn
- Turku PET Centre, Medicity Research Laboratory, University of Turku, Tykistökatu 6A, Turku, FI-20520, Finland ; Department of Oncology and Radiotherapy, Turku University Hospital, Turku, FI-20521, Finland
| | - Tove J Grönroos
- Turku PET Centre, Medicity Research Laboratory, University of Turku, Tykistökatu 6A, Turku, FI-20520, Finland ; Department of Oncology and Radiotherapy, Turku University Hospital, Turku, FI-20521, Finland
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Wuest M, Wuest F. Positron emission tomography radiotracers for imaging hypoxia. J Labelled Comp Radiopharm 2014; 56:244-50. [PMID: 24285331 DOI: 10.1002/jlcr.2997] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2012] [Revised: 07/27/2012] [Accepted: 11/06/2012] [Indexed: 11/11/2022]
Abstract
Localized hypoxia, the physiological hallmark of many clinical pathologies, is the consequence of acute or chronic ischemia in the affected region or tissue. The versatility, sensitivity, quantitative nature, and increasing availability of positron emission tomography (PET) make it the preclinical and clinical method of choice for functional imaging of tissue hypoxia at the molecular level. The progress and current status of radiotracers for hypoxia-specific PET imaging are reviewed in this article including references mainly focused on radiochemistry and also relevant to molecular imaging of hypoxia in preclinical and clinical studies.
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Affiliation(s)
- Melinda Wuest
- Department of Oncology, University of Alberta, Edmonton, AB, T6G 1Z2, Canada
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Komar G, Lehtiö K, Seppänen M, Eskola O, Levola H, Lindholm P, Sipilä H, Seppälä J, Grénman R, Solin O, Minn H. Prognostic value of tumour blood flow, [¹⁸F]EF5 and [¹⁸F]FDG PET/CT imaging in patients with head and neck cancer treated with radiochemotherapy. Eur J Nucl Med Mol Imaging 2014; 41:2042-50. [PMID: 24898846 DOI: 10.1007/s00259-014-2818-3] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2013] [Accepted: 05/19/2014] [Indexed: 12/22/2022]
Abstract
PURPOSE In order to improve the treatment of squamous cell carcinoma of the head and neck, precise information on the treated tumour's biology is required and the prognostic importance of different biological parameters needs to be determined. The aim of our study was to determine the predictive value of pretreatment PET/CT imaging using [(18)F]FDG, a new hypoxia tracer [(18)F]EF5 and the perfusion tracer [(15)O]H₂O in patients with squamous cell cancer of the head and neck treated with radiochemotherapy. METHODS The study group comprised 22 patients with confirmed squamous cell carcinoma of the head and neck who underwent a PET/CT scan using the above tracers before any treatment. Patients were later treated with a combination of radiochemotherapy and surgery. Parametric blood flow was calculated from dynamic [(15)O]H₂O PET images using a one-tissue compartment model. [(18)F]FDG images were analysed by calculating standardized uptake values (SUV) and metabolically active tumour volumes (MATV). [(18)F]EF5 images were analysed by calculating tumour-to-muscle uptake ratios (T/M ratio). A T/M ratio of 1.5 was considered a significant threshold and used to determine tumour hypoxic subvolumes (HS) and hypoxic fraction area. The findings were finally correlated with the pretreatment clinical findings (overall stage and TNM stage) as well as the outcome following radiochemotherapy in terms of local control and overall patient survival. RESULTS Tumour stage and T-classification did not show any significant differences in comparison to the patients' metabolic and functional characteristics measured on PET. Using the Cox proportional hazards model, a shorter overall survival was associated with MATV (p = 0.008, HR = 1.108), maximum [(18)F]EF5 T/M ratio (p = 0.0145, HR = 4.084) and tumour HS (p = 0.0047, HR = 1.112). None of the PET parameters showed a significant effect on patient survival in the log-rank test, although [(18)F]EF5 maximum T/M ratio was the closest (p = 0.109). By contrast, tumour blood flow was not correlated with any of the clinical endpoints. There were no statistically significant correlations among [(18)F]FDG SUVmax, [(18)F]EF5 T/M ratio and blood flow. CONCLUSION Our study in a limited number of patients confirmed the importance of MATV in the prognosis of locally advanced squamous cell carcinoma of the head and neck. It is of interest that high uptake of the hypoxia tracer [(18)F]EF5 showed a stronger correlation with a poor clinical outcome than [(18)F]FDG uptake. This confirms the importance of hypoxia in treatment outcome and suggests that [(18)F]EF5 may act as a surrogate marker of radioresistance.
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Affiliation(s)
- Gaber Komar
- Turku PET Centre, Kiinamyllynkatu 4-8, 20521, Turku, Finland,
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Silén J, Högel H, Kivinen K, Silvoniemi A, Forsback S, Löyttyniemi E, Solin O, Grénman R, Minn H, Jaakkola PM, Grönroos TJ. Uptake of [ 18F]EF5 as a Tracer for Hypoxic and Aggressive Phenotype in Experimental Head and Neck Squamous Cell Carcinoma. Transl Oncol 2014; 7:S1936-5233(14)00047-3. [PMID: 24862538 PMCID: PMC4145394 DOI: 10.1016/j.tranon.2014.04.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Revised: 03/17/2014] [Accepted: 03/19/2014] [Indexed: 11/30/2022] Open
Abstract
PURPOSE This study aims to investigate whether the uptake of 2-(2-nitro-1H-imidazol-1-yl)-N-(2,2,3,3,3-pentafluoropropyl)-acetamide ([18F]EF5) and 2-deoxy-2-[18F]fluoro-d-glucose ([18F]FDG) is associated with a hypoxia-driven adverse phenotype in head and neck squamous cell carcinoma cell lines and tumor xenografts. METHODS Xenografts were imaged in vivo, and tumor sections were stained for hypoxia-inducible factor 1α (Hif-1α), carbonic anhydrase IX (CA IX), and glucose transporter 1 (Glut-1). Tracer uptakes and the expression of Hif-1α were determined in cell lines under 1% hypoxia. RESULTS High [18F]EF5 uptake was seen in xenografts expressing high levels of CA IX, Glut-1, and Hif-1α, whereas low [18F]EF5 uptake was detected in xenografts expressing low amounts of CA IX and Hif-1α. The uptake of [18F]EF5 between cell lines varied extensively under normoxic conditions. A clear correlation was found between the expression of Hif-1α and the uptake of [18F]FDG during hypoxia. CONCLUSIONS The UT-SCC cell lines studied differed with respect to their hypoxic phenotypes, and these variations were detectable with [18F]EF5. Acute hypoxia increases [18F]FDG uptake in vitro, whereas a high [18F]EF5 uptake reflects a more complex phenotype associated with hypoxia and an aggressive growth pattern.
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Affiliation(s)
- Jonna Silén
- MediCity Research Laboratory, Turku PET Centre, University of Turku, Turku, Finland; Department of Oncology and Radiotherapy, Turku University Hospital, Turku, Finland
| | - Heidi Högel
- Turku Centre of Biotechnology, University of Turku, Turku, Finland
| | - Katri Kivinen
- Department of Pathology, University of Turku, Turku, Finland
| | - Antti Silvoniemi
- MediCity Research Laboratory, Turku PET Centre, University of Turku, Turku, Finland; Department of Otorhinolaryngology, Turku University Hospital, Turku, Finland
| | - Sarita Forsback
- MediCity Research Laboratory, Turku PET Centre, University of Turku, Turku, Finland
| | | | - Olof Solin
- MediCity Research Laboratory, Turku PET Centre, University of Turku, Turku, Finland
| | - Reidar Grénman
- Department of Otorhinolaryngology, Turku University Hospital, Turku, Finland
| | - Heikki Minn
- MediCity Research Laboratory, Turku PET Centre, University of Turku, Turku, Finland; Department of Oncology and Radiotherapy, Turku University Hospital, Turku, Finland
| | - Panu M Jaakkola
- Department of Oncology and Radiotherapy, Turku University Hospital, Turku, Finland; Turku Centre of Biotechnology, University of Turku, Turku, Finland
| | - Tove J Grönroos
- MediCity Research Laboratory, Turku PET Centre, University of Turku, Turku, Finland; Department of Oncology and Radiotherapy, Turku University Hospital, Turku, Finland.
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Chitneni SK, Bida GT, Zalutsky MR, Dewhirst MW. Comparison of the Hypoxia PET Tracer (18)F-EF5 to Immunohistochemical Marker EF5 in 3 Different Human Tumor Xenograft Models. J Nucl Med 2014; 55:1192-7. [PMID: 24854792 DOI: 10.2967/jnumed.114.137448] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Accepted: 04/07/2014] [Indexed: 12/16/2022] Open
Abstract
UNLABELLED The availability of (18)F-labeled and unlabeled 2-(2-nitro-1H-imidazol-1-yl)-N-(2,2,3,3,3-pentafluoropropyl)-acetamide (EF5) allows for a comparative assessment of tumor hypoxia by PET and immunohistochemistry; however, the combined use of these 2 approaches has not been fully assessed in vivo. The aim of this study was to evaluate (18)F-EF5 tumor uptake versus EF5 binding and hypoxia as determined from immunohistochemistry at both macroscopic and microregional levels. METHODS Three tumor models-PC3, HCT116, and H460-were evaluated. Tumor-bearing animals were coinjected with (18)F-EF5 and EF5 (30 mg/kg), and PET imaging was performed at 2.5 h after injection. After PET imaging and 2 min after Hoechst 33342 injection, the tumors were excised and evaluated for (18)F-EF5 distribution by autoradiography and EF5 binding by immunohistochemistry. Additionally, the effects of nonradioactive EF5 (30 mg/kg) on the hypoxia-imaging characteristics of (18)F-EF5 were evaluated by comparing the PET data for H460 tumors with those from animals injected with (18)F-EF5 alone. RESULTS The uptake of (18)F-EF5 in hypoxic tumor regions and the spatial relationship between (18)F-EF5 uptake and EF5 binding varied among tumors. H460 tumors showed higher tumor-to-muscle contrast in PET imaging; however, the distribution and uptake of the tracer was less specific for hypoxia in H460 than in HCT116 and PC3 tumors. Correlation analyses revealed that the highest spatial correlation between (18)F-EF5 uptake and EF5 binding was in PC3 tumors (r = 0.73 ± 0.02) followed by HCT116 (r = 0.60 ± 0.06) and H460 (r = 0.53 ± 0.10). Uptake and binding of (18)F-EF5 and EF5 correlated negatively with Hoechst 33342 perfusion marker distribution in the 3 tumor models. Image contrast and heterogeneous uptake of (18)F-EF5 in H460 tumors was significantly higher when the radiotracer was used alone versus in combination with unlabeled EF5 (tumor-to-muscle ratio of 2.51 ± 0.33 vs. 1.71 ± 0.17, P < 0.001). CONCLUSION The uptake and hypoxia selectivity of (18)F-EF5 varied among tumor models when animals also received nonradioactive EF5. Combined use of radioactive and nonradioactive EF5 for independent assessment of tumor hypoxia by PET and immunohistochemistry methods is promising; however, the EF5 drug concentrations that are required for immunohistochemistry assays may affect the uptake of (18)F-EF5 in hypoxic cells in certain tumor types as observed in H460 in this study.
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Affiliation(s)
- Satish K Chitneni
- Department of Radiology, Duke University Medical Center, Durham, North Carolina; and
| | - Gerald T Bida
- Department of Radiology, Duke University Medical Center, Durham, North Carolina; and
| | - Michael R Zalutsky
- Department of Radiology, Duke University Medical Center, Durham, North Carolina; and Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina
| | - Mark W Dewhirst
- Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina
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Horsman MR, Mortensen LS, Petersen JB, Busk M, Overgaard J. Imaging hypoxia to improve radiotherapy outcome. Nat Rev Clin Oncol 2012; 9:674-87. [DOI: 10.1038/nrclinonc.2012.171] [Citation(s) in RCA: 422] [Impact Index Per Article: 35.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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15
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Chitneni SK, Bida GT, Dewhirst MW, Zalutsky MR. A simplified synthesis of the hypoxia imaging agent 2-(2-Nitro-1H-imidazol-1-yl)-N-(2,2,3,3,3-[(18)F]pentafluoropropyl)-acetamide ([18F]EF5). Nucl Med Biol 2012; 39:1012-8. [PMID: 22727821 PMCID: PMC3478693 DOI: 10.1016/j.nucmedbio.2012.05.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2011] [Revised: 04/12/2012] [Accepted: 05/04/2012] [Indexed: 12/27/2022]
Abstract
INTRODUCTION [(18)F]EF5 is a validated marker for PET imaging of tumor hypoxia. It is prepared by reacting a trifluoroallyl precursor with carrier-added [(18)F]F(2) gas in trifluoroacetic acid (TFA) solvent. We report here an improved radiosynthesis and purification of [(18)F]EF5 by utilizing an electroformed nickel (Ni) target for [(18)F]F(2) production, and Oasis® HLB cartridges for on-line solid phase extraction of [(18)F]EF5 prior to HPLC purification. METHODS [(18)F]F(2) was produced by deuteron bombardment of neon plus F(2) in an Ni target, and bubbled through the radiolabelling precursor solution. Purification was achieved by extracting the contents of the crude reaction mixture onto Oasis HLB cartridges, and subsequently eluted onto a semi-preparative HPLC column for further separation. Purified [(18)F]EF5 was evaluated in small animal PET studies using HCT116 tumor xenografts in nude mice. RESULTS The electroformed Ni target enabled recovery of >75% of the radioactivity from the cyclotron target, resulting in 16.2 ± 2.2 GBq (438 ± 58 mCi) of [(18)F]F(2) available for the synthesis. Use of Oasis cartridges yielded a less complex mixture for purification. On average, 1140 ± 200 MBq (30.8 ± 5.4 mCi) of [(18)F]EF5 were collected at EOS. Small animal PET imaging studies showed specific retention of [(18)F]EF5 in tumors, with tumor-to-muscle ratios of 2.7 ± 0.3 at about 160 min after injection. CONCLUSION A simple procedure has been developed for the routine synthesis of [(18)F]EF5 in amounts and purity required for clinical studies. This new method avoids the need for TFA evaporation and also enables facile automation of the synthesis using commercially available radiosynthesis modules.
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Affiliation(s)
- Satish K. Chitneni
- Department of Radiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Gerald T. Bida
- Department of Radiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Mark W. Dewhirst
- Department of Radiation Oncology, Duke University Medical Center, Durham, NC 27710, USA
| | - Michael R. Zalutsky
- Department of Radiology, Duke University Medical Center, Durham, NC 27710, USA
- Department of Radiation Oncology, Duke University Medical Center, Durham, NC 27710, USA
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Abstract
In the past 25 y, a large amount of clinical experience with hypoxia PET tracers has accumulated. This article discusses recent improvements in image acquisition protocols and tracer pharmacology that have resulted in improved understanding of the underlying physiologic processes. The widespread clinical adoption of hypoxia PET tracers will depend largely on their utility in treatment prescription and in outcome monitoring. The establishment and validation of hypoxia-directed treatment protocols are still under development, and it is envisaged that the design and use of future hypoxia PET tracers will develop as part of this process.
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Affiliation(s)
- Sean Carlin
- Radiochemistry and Imaging Sciences Service, Department of Radiology, Memorial Sloan-Kettering Cancer Center, New York, NY, USA.
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