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Volpe A, Lyashchenko SK, Ponomarev V. Nuclear-Based Labeling of Cellular Immunotherapies: A Simple Protocol for Preclinical Use. Mol Imaging Biol 2024; 26:555-568. [PMID: 38958882 PMCID: PMC11281953 DOI: 10.1007/s11307-024-01923-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Revised: 05/10/2024] [Accepted: 05/18/2024] [Indexed: 07/04/2024]
Abstract
Labeling and tracking existing and emerging cell-based immunotherapies using nuclear imaging is widely used to guide the preclinical phases of development and testing of existing and new emerging off-the-shelf cell-based immunotherapies. In fact, advancing our knowledge about their mechanism of action and limitations could provide preclinical support and justification for moving towards clinical experimentation of newly generated products and expedite their approval by the Food and Drug Administration (FDA).Here we provide the reader with a ready to use protocol describing the labeling methodologies and practical procedures to render different candidate cell therapies in vivo traceable by nuclear-based imaging. The protocol includes sufficient practical details to aid researchers at all career stages and from different fields in familiarizing with the described concepts and incorporating them into their work.
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Affiliation(s)
- Alessia Volpe
- Department of Radiology, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY, 10065, USA
| | - Serge K Lyashchenko
- Department of Radiology, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY, 10065, USA
| | - Vladimir Ponomarev
- Department of Radiology, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY, 10065, USA.
- Center for Cell Engineering, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY, 10065, USA.
- Molecular Pharmacology and Chemistry Program, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY, 10065, USA.
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2
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Vrachliotis A, Gaitanis A, Protonotarios NE, Kastis GA, Costaridou L. Noninvasive Quantification of Glucose Metabolism in Mice Myocardium Using the Spline Reconstruction Technique. J Imaging 2024; 10:170. [PMID: 39057741 PMCID: PMC11278115 DOI: 10.3390/jimaging10070170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2024] [Revised: 06/25/2024] [Accepted: 07/12/2024] [Indexed: 07/28/2024] Open
Abstract
The spline reconstruction technique (SRT) is a fast algorithm based on a novel numerical implementation of an analytic representation of the inverse Radon transform. The purpose of this study was to compare the SRT, filtered back-projection (FBP), and the Tera-Tomo 3D algorithm for various iteration numbers, using small-animal dynamic PET data obtained from a Mediso nanoScan® PET/CT scanner. For this purpose, Patlak graphical kinetic analysis was employed to noninvasively quantify the myocardial metabolic rate of glucose (MRGlu) in seven male C57BL/6 mice (n=7). All analytic reconstructions were performed via software for tomographic image reconstruction. The analysis of all PET-reconstructed images was conducted with PMOD software (version 3.506, PMOD Technologies LLC, Fällanden, Switzerland) using the inferior vena cava as the image-derived input function. Statistical significance was determined by employing the one-way analysis of variance test. The results revealed that the differences between the values of MRGlu obtained via SRT versus FBP, and the variants of he Tera-Tomo 3D algorithm were not statistically significant (p > 0.05). Overall, the SRT appears to perform similarly to the other algorithms investigated, providing a valid alternative analytic method for preclinical dynamic PET studies.
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Affiliation(s)
- Alexandros Vrachliotis
- Department of Medical Physics, School of Medicine, University of Patras, 26504 Patras, Greece; (A.V.); (L.C.)
- Clinical, Experimental Surgery & Translational Research, Biomedical Research Foundation (BRFAA), Academy of Athens, 4 Soranou Ephessiou, 11527 Athens, Greece;
| | - Anastasios Gaitanis
- Clinical, Experimental Surgery & Translational Research, Biomedical Research Foundation (BRFAA), Academy of Athens, 4 Soranou Ephessiou, 11527 Athens, Greece;
| | - Nicholas E. Protonotarios
- Mathematics Research Center, Academy of Athens, 11527 Athens, Greece;
- Institute of Nuclear & Radiological Sciences & Technology, Energy & Safety, National Center for Scientific Research “Demokritos”, 15341 Athens, Greece
| | - George A. Kastis
- Mathematics Research Center, Academy of Athens, 11527 Athens, Greece;
- Institute of Nuclear & Radiological Sciences & Technology, Energy & Safety, National Center for Scientific Research “Demokritos”, 15341 Athens, Greece
| | - Lena Costaridou
- Department of Medical Physics, School of Medicine, University of Patras, 26504 Patras, Greece; (A.V.); (L.C.)
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Reconstruction of Preclinical PET Images via Chebyshev Polynomial Approximation of the Sinogram. APPLIED SCIENCES-BASEL 2022. [DOI: 10.3390/app12073335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Over the last decades, there has been an increasing interest in dedicated preclinical imaging modalities for research in biomedicine. Especially in the case of positron emission tomography (PET), reconstructed images provide useful information of the morphology and function of an internal organ. PET data, stored as sinograms, involve the Radon transform of the image under investigation. The analytical approach to PET image reconstruction incorporates the derivative of the Hilbert transform of the sinogram. In this direction, in the present work we present a novel numerical algorithm for the inversion of the Radon transform based on Chebyshev polynomials of the first kind. By employing these polynomials, the computation of the derivative of the Hilbert transform of the sinogram is significantly simplified. Extending the mathematical setting of previous research based on Chebyshev polynomials, we are able to efficiently apply our new Chebyshev inversion scheme for the case of analytic preclinical PET image reconstruction. We evaluated our reconstruction algorithm on projection data from a small-animal image quality (IQ) simulated phantom study, in accordance with the NEMA NU 4-2008 standards protocol. In particular, we quantified our reconstructions via the image quality metrics of percentage standard deviation, recovery coefficient, and spill-over ratio. The projection data employed were acquired for three different Poisson noise levels: 100% (NL1), 50% (NL2), and 20% (NL3) of the total counts, respectively. In the uniform region of the IQ phantom, Chebyshev reconstructions were consistently improved over filtered backprojection (FBP), in terms of percentage standard deviation (up to 29% lower, depending on the noise level). For all rods, we measured the contrast-to-noise-ratio, indicating an improvement of up to 68% depending on the noise level. In order to compare our reconstruction method with FBP, at equal noise levels, plots of recovery coefficient and spill-over ratio as functions of the percentage standard deviation were generated, after smoothing the NL3 reconstructions with three different Gaussian filters. When post-smoothing was applied, Chebyshev demonstrated recovery coefficient values up to 14% and 42% higher, for rods 1–3 mm and 4–5 mm, respectively, compared to FBP, depending on the smoothing sigma values. Our results indicate that our Chebyshev-based analytic reconstruction method may provide PET reconstructions that are comparable to FBP, thus yielding a good alternative to standard analytic preclinical PET reconstruction methods.
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Evaluation of [18F]tetrafluoroborate as a Potential PET Imaging Agent in a Sodium Iodide Symporter-Transfected Cell Line A549 and Endogenous NIS-Expressing Cell Lines MKN45 and K1. Mol Imaging 2022; 2022:2679260. [PMID: 35330799 PMCID: PMC8923191 DOI: 10.1155/2022/2679260] [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: 11/12/2021] [Accepted: 02/02/2022] [Indexed: 12/24/2022] Open
Abstract
[18F]tetrafluoroborate (TFB) has been introduced as the 18F-labeled PET imaging probe for the human sodium iodide symporter (NIS). Noninvasive NIS imaging using [18F]TFB has received much interest in recent years for evaluating various NIS-expressing tumors. Cancers are a global concern with enormous implications; therefore, improving diagnostic methods for accurate detection of cancer is extremely important. Our aim was to investigate the PET imaging capabilities of [18F]TFB in NIS-transfected lung cell line A549 and endogenous NIS-expressing tumor cells, such as thyroid cancer K1 and gastric cancer MKN45, and broaden its application in the medical field. Western blot and flow cytometry were used to assess the NIS expression level. Radioactivity counts of [18F]TFB, in vitro, in the three tumor cells were substantially higher than those in the KI inhibition group in the uptake experiment. In vivo PET imaging clearly delineated the three tumors based on the specific accumulation of [18F]TFB in a mouse model. Ex vivo biodistribution investigation showed high [18F]TFB absorption in the tumor location, which was consistent with the PET imaging results. These results support the use of NIS-transfected lung cell line A549 and NIS-expressing tumor cells MKN45 and K1, to investigate probing capabilities of [18F]TFB. We also demonstrate, for the first time, the feasibility of [18F]TFB in diagnosing stomach cancer. In conclusion, this study illustrates the promising future of [18F]TFB for tumor diagnosis and NIS reporter imaging.
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Fedrigo R, Kadrmas DJ, Edem PE, Fougner L, Klyuzhin IS, Petric MP, Bénard F, Rahmim A, Uribe C. Quantitative evaluation of PSMA PET imaging using a realistic anthropomorphic phantom and shell-less radioactive epoxy lesions. EJNMMI Phys 2022; 9:2. [PMID: 35032234 PMCID: PMC8761183 DOI: 10.1186/s40658-021-00429-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Accepted: 12/20/2021] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND Positron emission tomography (PET) with prostate specific membrane antigen (PSMA) have shown superior performance in detecting metastatic prostate cancers. Relative to [18F]fluorodeoxyglucose ([18F]FDG) PET images, PSMA PET images tend to visualize significantly higher-contrast focal lesions. We aim to evaluate segmentation and reconstruction algorithms in this emerging context. Specifically, Bayesian or maximum a posteriori (MAP) image reconstruction, compared to standard ordered subsets expectation maximization (OSEM) reconstruction, has received significant interest for its potential to reach convergence with minimal noise amplifications. However, few phantom studies have evaluated the quantitative accuracy of such reconstructions for high contrast, small lesions (sub-10 mm) that are typically observed in PSMA images. In this study, we cast 3 mm-16-mm spheres using epoxy resin infused with a long half-life positron emitter (sodium-22; 22Na) to simulate prostate cancer metastasis. The anthropomorphic Probe-IQ phantom, which features a liver, bladder, lungs, and ureters, was used to model relevant anatomy. Dynamic PET acquisitions were acquired and images were reconstructed with OSEM (varying subsets and iterations) and BSREM (varying β parameters), and the effects on lesion quantitation were evaluated. RESULTS The 22Na lesions were scanned against an aqueous solution containing fluorine-18 (18F) as the background. Regions-of-interest were drawn with MIM Software using 40% fixed threshold (40% FT) and a gradient segmentation algorithm (MIM's PET Edge+). Recovery coefficients (RCs) (max, mean, peak, and newly defined "apex"), metabolic tumour volume (MTV), and total tumour uptake (TTU) were calculated for each sphere. SUVpeak and SUVapex had the most consistent RCs for different lesion-to-background ratios and reconstruction parameters. The gradient-based segmentation algorithm was more accurate than 40% FT for determining MTV and TTU, particularly for lesions [Formula: see text] 6 mm in diameter (R2 = 0.979-0.996 vs. R2 = 0.115-0.527, respectively). CONCLUSION An anthropomorphic phantom was used to evaluate quantitation for PSMA PET imaging of metastatic prostate cancer lesions. BSREM with β = 200-400 and OSEM with 2-5 iterations resulted in the most accurate and robust measurements of SUVmean, MTV, and TTU for imaging conditions in 18F-PSMA PET/CT images. SUVapex, a hybrid metric of SUVmax and SUVpeak, was proposed for robust, accurate, and segmentation-free quantitation of lesions for PSMA PET.
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Affiliation(s)
- Roberto Fedrigo
- Department of Integrative Oncology, BC Cancer Research Institute, 675 W 10th Avenue, Vancouver, BC, V5Z1L3, Canada
- Department of Physics and Astronomy, University of British Columbia, 325-6224 Agricultural Road, Vancouver, BC, V6T1Z1, Canada
| | - Dan J Kadrmas
- Department of Radiology and Imaging Sciences, University of Utah, 201 Presidents' Cir, Salt Lake City, UT, 84112, USA
| | - Patricia E Edem
- Functional Imaging, BC Cancer, 600 W 10th Avenue, Vancouver, BC, V5Z4E6, Canada
| | - Lauren Fougner
- Functional Imaging, BC Cancer, 600 W 10th Avenue, Vancouver, BC, V5Z4E6, Canada
| | - Ivan S Klyuzhin
- Department of Integrative Oncology, BC Cancer Research Institute, 675 W 10th Avenue, Vancouver, BC, V5Z1L3, Canada
- Department of Physics and Astronomy, University of British Columbia, 325-6224 Agricultural Road, Vancouver, BC, V6T1Z1, Canada
| | - M Peter Petric
- Functional Imaging, BC Cancer, 600 W 10th Avenue, Vancouver, BC, V5Z4E6, Canada
| | - François Bénard
- Department of Integrative Oncology, BC Cancer Research Institute, 675 W 10th Avenue, Vancouver, BC, V5Z1L3, Canada
- Department of Physics and Astronomy, University of British Columbia, 325-6224 Agricultural Road, Vancouver, BC, V6T1Z1, Canada
- Department of Molecular Oncology, BC Cancer Research Institute, 675 W 10th Avenue, Vancouver, BC, V5Z1L3, Canada
| | - Arman Rahmim
- Department of Integrative Oncology, BC Cancer Research Institute, 675 W 10th Avenue, Vancouver, BC, V5Z1L3, Canada
- Department of Physics and Astronomy, University of British Columbia, 325-6224 Agricultural Road, Vancouver, BC, V6T1Z1, Canada
- Department of Radiology, University of British Columbia, 675 W 10th Avenue, Vancouver, BC, V5Z1L3, Canada
| | - Carlos Uribe
- Functional Imaging, BC Cancer, 600 W 10th Avenue, Vancouver, BC, V5Z4E6, Canada.
- Department of Radiology, University of British Columbia, 675 W 10th Avenue, Vancouver, BC, V5Z1L3, Canada.
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Xiao Z, Puré E. Imaging of T-cell Responses in the Context of Cancer Immunotherapy. Cancer Immunol Res 2021; 9:490-502. [PMID: 33941536 DOI: 10.1158/2326-6066.cir-20-0678] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 11/18/2020] [Accepted: 02/18/2021] [Indexed: 12/16/2022]
Abstract
Immunotherapy, which promotes the induction of cytotoxic T lymphocytes and enhances their infiltration into and function within tumors, is a rapidly expanding and evolving approach to treating cancer. However, many of the critical denominators for inducing effective anticancer immune responses remain unknown. Efforts are underway to develop comprehensive ex vivo assessments of the immune landscape of patients prior to and during response to immunotherapy. An important complementary approach to these efforts involves the development of noninvasive imaging approaches to detect immune targets, assess delivery of immune-based therapeutics, and evaluate responses to immunotherapy. Herein, we review the merits and limitations of various noninvasive imaging modalities (MRI, PET, and single-photon emission tomography) and discuss candidate targets for cellular and molecular imaging for visualization of T-cell responses at various stages along the cancer-immunity cycle in the context of immunotherapy. We also discuss the potential use of these imaging strategies in monitoring treatment responses and predicting prognosis for patients treated with immunotherapy.
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Affiliation(s)
- Zebin Xiao
- Department of Biomedical Sciences, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Ellen Puré
- Department of Biomedical Sciences, University of Pennsylvania, Philadelphia, Pennsylvania.
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Johnson LC, Guerraty MA, Moore SC, Metzler SD. Quantification of defect contrast in microSPECT imaging of a myocardial phantom. Phys Med Biol 2020; 65:175001. [PMID: 32369789 DOI: 10.1088/1361-6560/ab9065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Ischemic heart disease remains a significant public health concern, accentuating the importance of basic research and therapeutic studies of small animals in which myocardial changes can be reproducibly detected and quantified. Few or no studies have investigated the performance of microSPECT in quantifying myocardial lesions. We utilized three versions of a multi-compartment phantom containing two left ventricular myocardial compartments (one uniform and one with a transmural 'cold' defect), a ventricular blood pool, and a background compartment, where each version had a different myocardial wall thickness (0.75, 1.0 and 1.25 mm). Each compartment was imaged separately while acquiring list-mode data. The separate compartment data were manipulated into a single data set with a known defect contrast, blood-pool and background activity. Data were processed with background-free defect-contrast values of 0 (no defect), -0.25, -0.5, -0.75, and -1.0 (all defect), three ratios of blood-pool to myocardial activity, 0 (no blood pool activity), 0.1, and 0.2 (20% of the activity in the healthy myocardial compartment), and three ratios of uniform background 0 (no background activity), 0.1 and 0.2, relative to the healthy myocardial compartment. For each wall thickness, defect contrast, blood-pool, and background activity combination, 25 list-mode noise realizations were generated and reconstructed. Volumes of interest were drawn and used to determine mean contrast recovery coefficients (CRCs) over the noise ensembles. We developed a slope-analysis procedure to estimate a single CRC over all contrast levels, with resulting CRC values (for no blood-pool and no background) of 0.848, 0.946, and 0.834 for the 0.75, 1.0, and 1.25 mm wall thicknesses, respectively. We also determined and validated a reprocessing method to calculate an ideal CRC. This work demonstrates the quantitative abilities of microSPECT for myocardial-defect imaging utilizing CRC and establishes a framework for evaluating defect-imaging capabilities in other systems.
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Affiliation(s)
- Lindsay C Johnson
- Department of Radiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States of America
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Iafrate M, Fruhwirth GO. How Non-invasive in vivo Cell Tracking Supports the Development and Translation of Cancer Immunotherapies. Front Physiol 2020; 11:154. [PMID: 32327996 PMCID: PMC7152671 DOI: 10.3389/fphys.2020.00154] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 02/12/2020] [Indexed: 12/26/2022] Open
Abstract
Immunotherapy is a relatively new treatment regimen for cancer, and it is based on the modulation of the immune system to battle cancer. Immunotherapies can be classified as either molecular or cell-based immunotherapies, and both types have demonstrated promising results in a growing number of cancers. Indeed, several immunotherapies representing both classes are already approved for clinical use in oncology. While spectacular treatment successes have been reported, particularly for so-called immune checkpoint inhibitors and certain cell-based immunotherapies, they have also been accompanied by a variety of severe, sometimes life-threatening side effects. Furthermore, not all patients respond to immunotherapy. Hence, there is the need for more research to render these promising therapeutics more efficacious, more widely applicable, and safer to use. Whole-body in vivo imaging technologies that can interrogate cancers and/or immunotherapies are highly beneficial tools for immunotherapy development and translation to the clinic. In this review, we explain how in vivo imaging can aid the development of molecular and cell-based anti-cancer immunotherapies. We describe the principles of imaging host T-cells and adoptively transferred therapeutic T-cells as well as the value of traceable cancer cell models in immunotherapy development. Our emphasis is on in vivo cell tracking methodology, including important aspects and caveats specific to immunotherapies. We discuss a variety of associated experimental design aspects including parameters such as cell type, observation times/intervals, and detection sensitivity. The focus is on non-invasive 3D cell tracking on the whole-body level including aspects relevant for both preclinical experimentation and clinical translatability of the underlying methodologies.
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Affiliation(s)
| | - Gilbert O. Fruhwirth
- Imaging Therapy and Cancer Group, Department of Imaging Chemistry and Biology, School of Biomedical Engineering & Imaging Sciences, King’s College London, London, United Kingdom
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Krekorian M, Fruhwirth GO, Srinivas M, Figdor CG, Heskamp S, Witney TH, Aarntzen EH. Imaging of T-cells and their responses during anti-cancer immunotherapy. Theranostics 2019; 9:7924-7947. [PMID: 31656546 PMCID: PMC6814447 DOI: 10.7150/thno.37924] [Citation(s) in RCA: 68] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Accepted: 09/30/2019] [Indexed: 12/23/2022] Open
Abstract
Immunotherapy has proven to be an effective approach in a growing number of cancers. Despite durable clinical responses achieved with antibodies targeting immune checkpoint molecules, many patients do not respond. The common denominator for immunotherapies that have successfully been introduced in the clinic is their potential to induce or enhance infiltration of cytotoxic T-cells into the tumour. However, in clinical research the molecules, cells and processes involved in effective responses during immunotherapy remain largely obscure. Therefore, in vivo imaging technologies that interrogate T-cell responses in patients represent a powerful tool to boost further development of immunotherapy. This review comprises a comprehensive analysis of the in vivo imaging technologies that allow the characterisation of T-cell responses induced by anti-cancer immunotherapy, with emphasis on technologies that are clinically available or have high translational potential. Throughout we discuss their respective strengths and weaknesses, providing arguments for selecting the optimal imaging options for future research and patient management.
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Affiliation(s)
- Massis Krekorian
- Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences, Radboud university medical center, Nijmegen, The Netherlands
- Department of Radiology and Nuclear Medicine, Radboud university medical center, Nijmegen, The Netherlands
| | - Gilbert O. Fruhwirth
- Department of Imaging Chemistry and Biology, School of Biomedical Engineering and Imaging Sciences, Kings' College London, London, United Kingdom
| | - Mangala Srinivas
- Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences, Radboud university medical center, Nijmegen, The Netherlands
| | - Carl G. Figdor
- Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences, Radboud university medical center, Nijmegen, The Netherlands
| | - Sandra Heskamp
- Department of Radiology and Nuclear Medicine, Radboud university medical center, Nijmegen, The Netherlands
| | - Timothy H. Witney
- Department of Imaging Chemistry and Biology, School of Biomedical Engineering and Imaging Sciences, Kings' College London, London, United Kingdom
| | - Erik H.J.G. Aarntzen
- Department of Radiology and Nuclear Medicine, Radboud university medical center, Nijmegen, The Netherlands
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Forgacs A, Kallos-Balogh P, Nagy F, Krizsan AK, Garai I, Tron L, Dahlbom M, Balkay L. Activity painting: PET images of freely defined activity distributions applying a novel phantom technique. PLoS One 2019; 14:e0207658. [PMID: 30682024 PMCID: PMC6347296 DOI: 10.1371/journal.pone.0207658] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Accepted: 11/04/2018] [Indexed: 12/18/2022] Open
Abstract
The aim of this work was to develop a novel phantom that supports the construction of highly reproducible phantoms with arbitrary activity distributions for PET imaging. It could offer a methodology for answering questions related to texture measurements in PET imaging. The basic idea is to move a point source on a 3-D trajectory in the field of view, while continuously acquiring data. The reconstruction results in a 3-D activity concentration map according to the pathway of the point source. A 22Na calibration point source was attached to a high precision robotic arm system, where the 3-D movement was software controlled. 3-D activity distributions of a homogeneous cube, a sphere, a spherical shell and a heart shape were simulated. These distributions were used to measure uniformity and to characterize reproducibility. Two potential applications using the lesion simulation method are presented: evaluation in changes of textural properties related to the position in the PET field of view; scanner comparison based on visual and quantitative evaluation of texture features. A lesion with volume of 50x50x50 mm3 can be simulated during approximately 1 hour. The reproducibility of the movement was found to be >99%. The coefficients of variation of the voxels within a simulated homogeneous cube was 2.34%. Based on 5 consecutive and independent measurements of a 36 mm diameter hot sphere, the coefficient of variation of the mean activity concentration was 0.68%. We obtained up to 18% differences within the values of investigated textural indexes, when measuring a lesion in different radial positions of the PET field of view. In comparison of two different human PET scanners the percentage differences between heterogeneity parameters were in the range of 5-55%. After harmonizing the voxel sizes this range reduced to 2-16%. The general activity distributions provided by the two different vendor show high similarity visually. For the demonstration of the flexibility of this method, the same pattern was also simulated on a small animal PET scanner giving similar results, both quantitatively and visually. 3-D motion of a point source in the PET field of view is capable to create an irregular shaped activity distribution with high reproducibility.
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Affiliation(s)
- Attila Forgacs
- Scanomed Nuclear Medicine Center, Debrecen, Hungary
- Division of Nuclear Medicine, Department of Medical Imaging, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Piroska Kallos-Balogh
- Division of Nuclear Medicine, Department of Medical Imaging, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Ferenc Nagy
- Scanomed Nuclear Medicine Center, Debrecen, Hungary
| | | | - Ildiko Garai
- Scanomed Nuclear Medicine Center, Debrecen, Hungary
- Division of Nuclear Medicine, Department of Medical Imaging, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Lajos Tron
- Division of Nuclear Medicine, Department of Medical Imaging, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Magnus Dahlbom
- Ahmanson Translational Imaging Division, University of California at Los Angeles, United States of America
| | - Laszlo Balkay
- Division of Nuclear Medicine, Department of Medical Imaging, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
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11
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Volpe A, Kurtys E, Fruhwirth GO. Cousins at work: How combining medical with optical imaging enhances in vivo cell tracking. Int J Biochem Cell Biol 2018; 102:40-50. [PMID: 29960079 PMCID: PMC6593261 DOI: 10.1016/j.biocel.2018.06.008] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 06/25/2018] [Accepted: 06/26/2018] [Indexed: 12/11/2022]
Abstract
Microscopy and medical imaging are related in their exploitation of electromagnetic waves, but were developed to satisfy differing needs, namely to observe small objects or to look inside subjects/objects, respectively. Together, these techniques can help elucidate complex biological processes and better understand health and disease. A current major challenge is to delineate mechanisms governing cell migration and tissue invasion in organismal development, the immune system and in human diseases such as cancer where the spatiotemporal tracking of small cell numbers in live animal models is extremely challenging. Multi-modal multi-scale in vivo cell tracking integrates medical and optical imaging. Fuelled by basic research in cancer biology and cell-based therapeutics, it has been enabled by technological advances providing enhanced resolution, sensitivity and multiplexing capabilities. Here, we review which imaging modalities have been successfully used for in vivo cell tracking and how this challenging task has benefitted from combining macroscopic with microscopic techniques.
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Affiliation(s)
- Alessia Volpe
- Department of Imaging Chemistry and Biology, School of Biomedical Engineering and Imaging Sciences, King's College London, SE1 7EH, London, UK
| | - Ewelina Kurtys
- Department of Imaging Chemistry and Biology, School of Biomedical Engineering and Imaging Sciences, King's College London, SE1 7EH, London, UK
| | - Gilbert O Fruhwirth
- Department of Imaging Chemistry and Biology, School of Biomedical Engineering and Imaging Sciences, King's College London, SE1 7EH, London, UK.
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12
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Volpe A, Man F, Lim L, Khoshnevisan A, Blower J, Blower PJ, Fruhwirth GO. Radionuclide-fluorescence Reporter Gene Imaging to Track Tumor Progression in Rodent Tumor Models. J Vis Exp 2018:57088. [PMID: 29608157 PMCID: PMC5931757 DOI: 10.3791/57088] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Metastasis is responsible for most cancer deaths. Despite extensive research, the mechanistic understanding of the complex processes governing metastasis remains incomplete. In vivo models are paramount for metastasis research, but require refinement. Tracking spontaneous metastasis by non-invasive in vivo imaging is now possible, but remains challenging as it requires long-time observation and high sensitivity. We describe a longitudinal combined radionuclide and fluorescence whole-body in vivo imaging approach for tracking tumor progression and spontaneous metastasis. This reporter gene methodology employs the sodium iodide symporter (NIS) fused to a fluorescent protein (FP). Cancer cells are engineered to stably express NIS-FP followed by selection based on fluorescence-activated cell sorting. Corresponding tumor models are established in mice. NIS-FP expressing cancer cells are tracked non-invasively in vivo at the whole-body level by positron emission tomography (PET) using the NIS radiotracer [18F]BF4-. PET is currently the most sensitive in vivo imaging technology available at this scale and enables reliable and absolute quantification. Current methods either rely on large cohorts of animals that are euthanized for metastasis assessment at varying time points, or rely on barely quantifiable 2D imaging. The advantages of the described method are: (i) highly sensitive non-invasive in vivo 3D PET imaging and quantification, (ii) automated PET tracer production, (iii) a significant reduction in required animal numbers due to repeat imaging options, (iv) the acquisition of paired data from subsequent imaging sessions providing better statistical data, and (v) the intrinsic option for ex vivo confirmation of cancer cells in tissues by fluorescence microscopy or cytometry. In this protocol, we describe all steps required for routine NIS-FP-afforded non-invasive in vivo cancer cell tracking using PET/CT and ex vivo confirmation of in vivo results. This protocol has applications beyond cancer research whenever in vivo localization, expansion and long-time monitoring of a cell population is of interest.
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Affiliation(s)
- Alessia Volpe
- Department of Imaging Chemistry and Biology, School of Biomedical Engineering and Imaging Sciences, King's College London
| | - Francis Man
- Department of Imaging Chemistry and Biology, School of Biomedical Engineering and Imaging Sciences, King's College London
| | - Lindsay Lim
- Department of Imaging Chemistry and Biology, School of Biomedical Engineering and Imaging Sciences, King's College London
| | - Alex Khoshnevisan
- Department of Imaging Chemistry and Biology, School of Biomedical Engineering and Imaging Sciences, King's College London
| | - Julia Blower
- Department of Imaging Chemistry and Biology, School of Biomedical Engineering and Imaging Sciences, King's College London
| | - Philip J Blower
- Department of Imaging Chemistry and Biology, School of Biomedical Engineering and Imaging Sciences, King's College London
| | - Gilbert O Fruhwirth
- Department of Imaging Chemistry and Biology, School of Biomedical Engineering and Imaging Sciences, King's College London;
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13
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Jonasson LS, Axelsson J, Riklund K, Boraxbekk CJ. Simulating effects of brain atrophy in longitudinal PET imaging with an anthropomorphic brain phantom. Phys Med Biol 2017; 62:5213-5227. [PMID: 28561014 DOI: 10.1088/1361-6560/aa6e1b] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
In longitudinal positron emission tomography (PET), the presence of volumetric changes over time can lead to an overestimation or underestimation of the true changes in the quantified PET signal due to the partial volume effect (PVE) introduced by the limited spatial resolution of existing PET cameras and reconstruction algorithms. Here, a 3D-printed anthropomorphic brain phantom with attachable striata in three sizes was designed to enable controlled volumetric changes. Using a method to eliminate the non-radioactive plastic wall, and manipulating BP levels by adding different number of events from list-mode acquisitions, we investigated the artificial volume dependence of BP due to PVE, and potential bias arising from varying BP. Comparing multiple reconstruction algorithms we found that a high-resolution ordered-subsets maximization algorithm with spatially variant point-spread function resolution modeling provided the most accurate data. For striatum, the BP changed by 0.08% for every 1% volume change, but for smaller volumes such as the posterior caudate the artificial change in BP was as high as 0.7% per 1% volume change. A simple gross correction for striatal volume is unsatisfactory, as the amplitude of the PVE on the BP differs depending on where in the striatum the change occurred. Therefore, to correctly interpret age-related longitudinal changes in the BP, we must account for volumetric changes also within a structure, rather than across the whole volume. The present 3D-printing technology, combined with the wall removal method, can be implemented to gain knowledge about the predictable bias introduced by the PVE differences in uptake regions of varying shape.
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Affiliation(s)
- L S Jonasson
- Department of Radiation Sciences, Diagnostic Radiology, Umeå University, Umeå, Sweden. Umeå Center for Functional Brain Imaging, Umeå University, Umeå, Sweden. Center for Demographic and Aging Research, Umeå University, Umeå Sweden
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14
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Diocou S, Volpe A, Jauregui-Osoro M, Boudjemeline M, Chuamsaamarkkee K, Man F, Blower PJ, Ng T, Mullen GED, Fruhwirth GO. [ 18F]tetrafluoroborate-PET/CT enables sensitive tumor and metastasis in vivo imaging in a sodium iodide symporter-expressing tumor model. Sci Rep 2017; 7:946. [PMID: 28424464 PMCID: PMC5430436 DOI: 10.1038/s41598-017-01044-4] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Accepted: 03/22/2017] [Indexed: 12/22/2022] Open
Abstract
Cancer cell metastasis is responsible for most cancer deaths. Non-invasive in vivo cancer cell tracking in spontaneously metastasizing tumor models still poses a challenge requiring highest sensitivity and excellent contrast. The goal of this study was to evaluate if the recently introduced PET radiotracer [18F]tetrafluoroborate ([18F]BF4-) is useful for sensitive and specific metastasis detection in an orthotopic xenograft breast cancer model expressing the human sodium iodide symporter (NIS) as a reporter. In vivo imaging was complemented by ex vivo fluorescence microscopy and γ-counting of harvested tissues. Radionuclide imaging with [18F]BF4- (PET/CT) was compared to the conventional tracer [123I]iodide (sequential SPECT/CT). We found that [18F]BF4- was superior due to better pharmacokinetics, i.e. faster tumor uptake and faster and more complete clearance from circulation. [18F]BF4--PET was also highly specific as in all detected tissues cancer cell presence was confirmed microscopically. Undetected comparable tissues were similarly found to be free of metastasis. Metastasis detection by routine metabolic imaging with [18F]FDG-PET failed due to low standard uptake values and low contrast caused by adjacent metabolically active organs in this model. [18F]BF4--PET combined with NIS expressing disease models is particularly useful whenever preclinical in vivo cell tracking is of interest.
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Affiliation(s)
- S Diocou
- King's College London, Imaging Chemistry and Biology, Division of Imaging Sciences and Biomedical Engineering, 4th Floor Lambeth Wing, St. Thomas' Hospital, London, SE1 7EH, UK
| | - A Volpe
- King's College London, Imaging Chemistry and Biology, Division of Imaging Sciences and Biomedical Engineering, 4th Floor Lambeth Wing, St. Thomas' Hospital, London, SE1 7EH, UK
| | - M Jauregui-Osoro
- King's College London, Imaging Chemistry and Biology, Division of Imaging Sciences and Biomedical Engineering, 4th Floor Lambeth Wing, St. Thomas' Hospital, London, SE1 7EH, UK
| | - M Boudjemeline
- King's College London, Imaging Chemistry and Biology, Division of Imaging Sciences and Biomedical Engineering, 4th Floor Lambeth Wing, St. Thomas' Hospital, London, SE1 7EH, UK
| | - K Chuamsaamarkkee
- King's College London, Imaging Chemistry and Biology, Division of Imaging Sciences and Biomedical Engineering, 4th Floor Lambeth Wing, St. Thomas' Hospital, London, SE1 7EH, UK
| | - F Man
- King's College London, Imaging Chemistry and Biology, Division of Imaging Sciences and Biomedical Engineering, 4th Floor Lambeth Wing, St. Thomas' Hospital, London, SE1 7EH, UK
| | - P J Blower
- King's College London, Imaging Chemistry and Biology, Division of Imaging Sciences and Biomedical Engineering, 4th Floor Lambeth Wing, St. Thomas' Hospital, London, SE1 7EH, UK
| | - T Ng
- King's College London, The Richard Dimbleby Department of Cancer Research, Randall Division of Molecular Biophysics and Cancer Division, Guy's Campus, London, SE1 1UL, UK
- UCL, Cancer Institute, Paul O'Gorman Building, London, WC1E 6BT, UK
| | - G E D Mullen
- King's College London, Imaging Chemistry and Biology, Division of Imaging Sciences and Biomedical Engineering, 4th Floor Lambeth Wing, St. Thomas' Hospital, London, SE1 7EH, UK.
| | - G O Fruhwirth
- King's College London, Imaging Chemistry and Biology, Division of Imaging Sciences and Biomedical Engineering, 4th Floor Lambeth Wing, St. Thomas' Hospital, London, SE1 7EH, UK.
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15
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Krizsan AK, Lajtos I, Dahlbom M, Daver F, Emri M, Kis SA, Opposits G, Pohubi L, Potari N, Hegyesi G, Kalinka G, Gal J, Imrek J, Nagy F, Valastyan I, Kiraly B, Molnar J, Sanfilippo D, Balkay L. A Promising Future: Comparable Imaging Capability of MRI-Compatible Silicon Photomultiplier and Conventional Photosensor Preclinical PET Systems. J Nucl Med 2015; 56:1948-53. [PMID: 26449836 DOI: 10.2967/jnumed.115.157677] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Accepted: 08/12/2015] [Indexed: 11/16/2022] Open
Abstract
UNLABELLED We recently completed construction of a small-animal PET system-the MiniPET-3-that uses state-of-the-art silicon photomultiplier (SiPM) photosensors, making possible dual-modality imaging with MRI. In this article, we compare the MiniPET-3 with the MiniPET-2, a system with the same crystal geometry but conventional photomultiplier tubes (PMTs). METHODS The standard measurements proposed by the National Electrical Manufacturers Association NU 4 protocols were performed on both systems. These measurements included spatial resolution, system sensitivity, energy resolution, counting rate performance, scatter fraction, spillover ratio for air and water, recovery coefficient, and image uniformity. The energy windows were set to 350-650 keV on the MiniPET-2 and 360-662 keV on the MiniPET-3. RESULTS Spatial resolution was approximately 17% better on average for the MiniPET-3 than the MiniPET-2. The systems performed similarly in terms of peak absolute sensitivity (∼1.37%), spillover ratio for air (∼0.15), spillover ratio for water (∼0.25), and recovery coefficient (∼0.33, 0.59, 0.81, 0.89, and 0.94). Uniformity was 5.59% for the MiniPET-2 and 6.49% for the MiniPET-3. Minor differences were found in scatter fraction. With the ratlike phantom, the peak noise-equivalent counting rate was 14 kcps on the MiniPET-2 but 24 kcps on the MiniPET-3. However, with the mouselike phantom, these values were 55 and 91 kcps, respectively. The optimal coincidence time window was 6 ns for the MiniPET-2 and 8 ns for the MiniPET-3. CONCLUSION Images obtained with the SiPM-based MiniPET-3 small-animal PET system are similar in quality to those obtained with the conventional PMT-based MiniPET-2.
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Affiliation(s)
- Aron K Krizsan
- Department of Nuclear Medicine, Medical Center, University of Debrecen, Debrecen, Hungary
| | - Imre Lajtos
- Department of Nuclear Medicine, Medical Center, University of Debrecen, Debrecen, Hungary
| | - Magnus Dahlbom
- Ahmanson Biological Imaging Center, Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at University of California, Los Angeles, California
| | - Freddie Daver
- Alfred Mann Institute for Biomedical Engineering, University of Southern California, Los Angeles, California
| | - Miklos Emri
- Department of Nuclear Medicine, Medical Center, University of Debrecen, Debrecen, Hungary
| | - Sandor A Kis
- Department of Nuclear Medicine, Medical Center, University of Debrecen, Debrecen, Hungary
| | - Gabor Opposits
- Department of Nuclear Medicine, Medical Center, University of Debrecen, Debrecen, Hungary
| | - Laszlo Pohubi
- Department of Nuclear Medicine, Medical Center, University of Debrecen, Debrecen, Hungary
| | - Norbert Potari
- Department of Nuclear Medicine, Medical Center, University of Debrecen, Debrecen, Hungary
| | - Gyula Hegyesi
- Institute for Nuclear Research, Hungarian Academy of Sciences, Debrecen, Hungary; and
| | - Gabor Kalinka
- Institute for Nuclear Research, Hungarian Academy of Sciences, Debrecen, Hungary; and
| | - Janos Gal
- Institute for Nuclear Research, Hungarian Academy of Sciences, Debrecen, Hungary; and
| | - Jozsef Imrek
- Institute for Nuclear Research, Hungarian Academy of Sciences, Debrecen, Hungary; and
| | - Ferenc Nagy
- Institute for Nuclear Research, Hungarian Academy of Sciences, Debrecen, Hungary; and
| | - Ivan Valastyan
- Institute for Nuclear Research, Hungarian Academy of Sciences, Debrecen, Hungary; and
| | - Beata Kiraly
- Institute for Nuclear Research, Hungarian Academy of Sciences, Debrecen, Hungary; and
| | - Jozsef Molnar
- Institute for Nuclear Research, Hungarian Academy of Sciences, Debrecen, Hungary; and
| | | | - Laszlo Balkay
- Department of Nuclear Medicine, Medical Center, University of Debrecen, Debrecen, Hungary
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