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Assessment of mouse-specific pharmacokinetics in kidneys based on 131I activity measurements using micro-SPECT. EJNMMI Phys 2022; 9:13. [PMID: 35195790 PMCID: PMC8866625 DOI: 10.1186/s40658-022-00443-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Accepted: 02/10/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND In order to acquire accurate drug pharmacokinetic information, which is required for tissue dosimetry, micro-SPECT must be quantitative to allow for an accurate assessment of radioligand activity in the relevant tissue. This study investigates the feasibility of deriving accurate mouse-specific time-integrated drug pharmacokinetic data in mouse kidneys from activity measurements using micro-SPECT. METHODS An animal experiment was carried out to evaluate the accuracy of 131I activity quantification in mouse kidneys (mean tissue volume of 0.140 mL) using a micro-SPECT system against conventional ex vivo gamma counting (GC) in a NaI(Tl) detector. The imaging setting investigated was that of the mouse biodistribution of a 131I-labelled single-domain antibody fragment (sdAb), currently being investigated for targeted radionuclide therapy of HER2-expressing cancer. SPECT imaging of 131I 365-keV photons was done with a VECTor/CT system (MILabs, Netherlands) using a high-energy mouse collimator with 1.6-mm-diameter pinholes. For both activity quantification techniques, the pharmacokinetic profile of the radioligand from approximately 1-73 h p.i. was derived and the time-integrated activity coefficient per gram of tissue (ã/M) was estimated. Additionally, SPECT activity recovery coefficients were determined in a phantom setting. RESULTS SPECT activities underestimate the reference activities by an amount that is dependent on the 131I activity concentration in the kidney, and thus on the time point of the pharmacokinetic profile. This underestimation is around - 12% at 1.5 h (2.89 MBq mL-1 mean reference activity concentration), - 13% at 6.6 h (149 kBq mL-1), - 40% at 24 h (17.6 kBq mL-1) and - 46% at 73 h (5.2 kBq mL-1) p.i. The ã/M value estimated from SPECT activities is, nevertheless, within - 14% from the reference (GC) ã/M value. Furthermore, better quantitative accuracy (within 2% from GC) in the SPECT ã/M value is achieved when SPECT activities are compensated for partial recovery with a phantom-based recovery coefficient of 0.85. CONCLUSION The SPECT imaging system used, together with a robust activity quantification methodology, allows an accurate estimation of time-integrated pharmacokinetic information of the 131I-labelled sdAb in mouse kidneys. This opens the possibility to perform mouse-specific kidney-tissue dosimetry based on pharmacokinetic data acquired in vivo on the same mice used in nephrotoxicity studies.
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Kiraga Ł, Kucharzewska P, Paisey S, Cheda Ł, Domańska A, Rogulski Z, Rygiel TP, Boffi A, Król M. Nuclear imaging for immune cell tracking in vivo – Comparison of various cell labeling methods and their application. Coord Chem Rev 2021. [DOI: 10.1016/j.ccr.2021.214008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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Beekman FJ, Kamphuis C, Koustoulidou S, Ramakers RM, Goorden MC. Positron range-free and multi-isotope tomography of positron emitters. Phys Med Biol 2021; 66:065011. [PMID: 33578400 DOI: 10.1088/1361-6560/abe5fc] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Despite improvements in small animal PET instruments, many tracers cannot be imaged at sufficiently high resolutions due to positron range, while multi-tracer PET is hampered by the fact that all annihilation photons have equal energies. Here we realize multi-isotope and sub-mm resolution PET of isotopes with several mm positron range by utilizing prompt gamma photons that are commonly neglected. A PET-SPECT-CT scanner (VECTor/CT, MILabs, The Netherlands) equipped with a high-energy cluster-pinhole collimator was used to image 124I and a mix of 124I and 18F in phantoms and mice. In addition to positrons (mean range 3.4 mm) 124I emits large amounts of 603 keV prompt gammas that-aided by excellent energy discrimination of NaI-were selected to reconstruct 124I images that are unaffected by positron range. Photons detected in the 511 keV window were used to reconstruct 18F images. Images were reconstructed iteratively using an energy dependent matrix for each isotope. Correction of 18F images for contamination with 124I annihilation photons was performed by Monte Carlo based range modelling and scaling of the 124I prompt gamma image before subtracting it from the 18F image. Additionally, prompt gamma imaging was tested for 89Zr that emits very high-energy prompts (909 keV). In Derenzo resolution phantoms 0.75 mm rods were clearly discernable for 124I, 89Zr and for simultaneously acquired 124I and 18F imaging. Image quantification in phantoms with reservoirs filled with both 124I and 18F showed excellent separation of isotopes and high quantitative accuracy. Mouse imaging showed uptake of 124I in tiny thyroid parts and simultaneously injected 18F-NaF in bone structures. The ability to obtain PET images at sub-mm resolution both for isotopes with several mm positron range and for multi-isotope PET adds to many other unique capabilities of VECTor's clustered pinhole imaging, including simultaneous sub-mm PET-SPECT and theranostic high energy SPECT.
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Affiliation(s)
- F J Beekman
- Department of Radiation Science and Technology, Delft University of Technology, Mekelweg 15, 2629 JB Delft, The Netherlands. MILabs B.V., Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands. Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, The Netherlands
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Nguyen MP, Goorden MC, Beekman FJ. EXIRAD-HE: multi-pinhole high-resolution ex vivo imaging of high-energy isotopes. ACTA ACUST UNITED AC 2020; 65:225029. [DOI: 10.1088/1361-6560/abbb77] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Goorden MC, Kamphuis C, Ramakers RM, Beekman FJ. Accelerated image reconstruction by a combined dual-matrix dual-voxel approach. ACTA ACUST UNITED AC 2020; 65:105014. [DOI: 10.1088/1361-6560/ab82e9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Metzler SD, Moore SC. Analytic Determination of Rectangular-Pinhole Sensitivity With Penetration. IEEE TRANSACTIONS ON MEDICAL IMAGING 2020; 39:833-843. [PMID: 31425068 PMCID: PMC7241287 DOI: 10.1109/tmi.2019.2936187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Modern small-animal SPECT systems use multiple pinhole collimators per detector to increase sensitivity while still maintaining high resolution. This resolution is a combination of aperture resolution combined with detector resolution, which is mitigated by magnification. Higher magnification results in better resolution, but fewer apertures per detector. When multiple pinhole collimators project onto the same detector, those with a rectangular field of view (FOV) can be packed more tightly than those with a circular FOV. In addition, a rectangular aperture can be used to obtain different resolution-sensitivity tradeoffs in the two orthogonal directions. Thus, these rectangular-pinhole collimators can have independent FOVs and independent resolution values in the two directions of the rectangular aperture. Previous work has determined the amount of penetration for circular pinholes (i.e., circular apertures with circular FOVs), where the pinhole walls were modeled as cones. In this work, a formula for the penetrative sensitivity for rectangular apertures with a rectangular FOV is determined. The formula was validated using numerical calculations for various combinations of acceptance angles, aperture sizes, linear attenuation coefficients, and incidence angles.
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Abstract
Molecular imaging enables both spatial and temporal understanding of the complex biologic systems underlying carcinogenesis and malignant spread. Single-photon emission tomography (SPECT) is a versatile nuclear imaging-based technique with ideal properties to study these processes in vivo in small animal models, as well as to identify potential drug candidates and characterize their antitumor action and potential adverse effects. Small animal SPECT and SPECT-CT (single-photon emission tomography combined with computer tomography) systems continue to evolve, as do the numerous SPECT radiopharmaceutical agents, allowing unprecedented sensitivity and quantitative molecular imaging capabilities. Several of these advances, their specific applications in oncology as well as new areas of exploration are highlighted in this chapter.
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Affiliation(s)
- Benjamin L Franc
- Department of Radiology, Stanford University School of Medicine, 300 Pasteur Drive, H2232, MC 5281, Stanford, CA, 94305-5105, USA.
| | - Youngho Seo
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, USA
| | - Robert Flavell
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, USA
| | - Carina Mari Aparici
- Department of Radiology, Stanford University School of Medicine, 300 Pasteur Drive, H2232, MC 5281, Stanford, CA, 94305-5105, USA
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Asmi H, Bentayeb F, Bouzekraoui Y, Bonutti F. Evaluation of Acceptance Angle in Iodine-131 Single Photon Emission Computed Tomography Imaging with Monte Carlo Simulation. Indian J Nucl Med 2019; 34:24-26. [PMID: 30713374 PMCID: PMC6352644 DOI: 10.4103/ijnm.ijnm_109_18] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Introduction In iodine-131 (I-131) imaging, the image quality is degraded by scatter and penetration in a collimator. In this work, we assessed the penetrated and the scattered photon fractions in the photopeak energy window using Monte Carlo Simulation code. Materials and Methods The Siemens Medical System equipped with high-energy collimator was simulated. We evaluated the acceptance angle values on geometric, penetration, and scatter components in a separate file. Binary images in a data file are obtained and each one of them was imported in software ImageJ. Full-width at half-maximum (FWHM) and sensitivity were calculated and compared. Results The simulation data show that for the acceptance angle value equal to 4.845°, the geometric, scatter, and penetration components were 93.20%, 4.13%, and 2.67%, respectively. Moreover, the resolution is improved (FWHM = 7.21 mm, full width at tenth maximum = 12.36 mm) for a point source at 12 cm from the detector. Conclusion The small acceptance angle has a major impact on the image quality in I-131 single photon emission computed tomography.
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Affiliation(s)
- Hicham Asmi
- Department of Physics, LPHE, Modeling and Simulations, Faculty of Science, Mohammed V University, Rabat, Morocco
| | - Farida Bentayeb
- Department of Physics, LPHE, Modeling and Simulations, Faculty of Science, Mohammed V University, Rabat, Morocco
| | - Youssef Bouzekraoui
- Department of Physics, LPHE, Modeling and Simulations, Faculty of Science, Mohammed V University, Rabat, Morocco
| | - Faustino Bonutti
- Department of Medical Physics, Academic Hospital of Udine, Udine, Italy
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Esquinas PL, Rodríguez-Rodríguez C, Esposito TVF, Harboe J, Bergamo M, Celler A, Saatchi K, Sossi V, Häfeli UO. Dual SPECT imaging of 111In and 67Ga to simultaneously determine in vivo the pharmacokinetics of different radiopharmaceuticals: a quantitative tool in pre-clinical research. ACTA ACUST UNITED AC 2018; 63:235029. [DOI: 10.1088/1361-6560/aaef63] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Chen Y, Vastenhouw B, Wu C, Goorden MC, Beekman FJ. Optimized image acquisition for dopamine transporter imaging with ultra-high resolution clinical pinhole SPECT. ACTA ACUST UNITED AC 2018; 63:225002. [DOI: 10.1088/1361-6560/aae76c] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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Heo D, Ku M, Kim JH, Yang J, Suh JS. Aptamer-Modified Magnetic Nanosensitizer for In Vivo MR Imaging of HER2-Expressing Cancer. NANOSCALE RESEARCH LETTERS 2018; 13:288. [PMID: 30229394 PMCID: PMC6143495 DOI: 10.1186/s11671-018-2682-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/10/2017] [Accepted: 08/21/2018] [Indexed: 06/08/2023]
Abstract
The aim of this study was the development of a human epidermal growth factor receptor 2 (HER2)-targetable contrast agent for magnetic resonance imaging (MRI) with a high magnetic sensitivity. An anti-HER2 aptamer-modified magnetic nanosensitizer (AptHER2-MNS) was prepared by conjugation with 5'-thiol-modified aptamers and maleimidylated magnetic nanocrystals (MNCs). The physicochemical characteristics and targeting ability of AptHER2-MNS were confirmed, and the binding affinity (Kd) onto HER2 protein of AptHER2-MNS was 0.57 ± 0.26 nM. In vivo MRI contrast enhancement ability was also verified at HER2+ cancer cell (NIH3T6.7)-xenograft mouse models (n = 3) at 3T clinical MRI instrument. The control experiment was carried out using non-labeled MNCs. The results indicated that up to 150% contrast enhancement was achieved at the tumor region in the T2-weighted MR images after the injection of the AptHER2-MNS agent in mice that received the NIH3T6.7 cells.
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Affiliation(s)
- Dan Heo
- Department of Radiology, Yonsei University College of Medicine, Seoul, 03722 Republic of Korea
| | - Minhee Ku
- Department of Radiology, Yonsei University College of Medicine, Seoul, 03722 Republic of Korea
- Systems Molecular Radiology at Yonsei, Seoul, 03722 Republic of Korea
| | - Jung-Hoon Kim
- Department of Radiology, Yonsei University College of Medicine, Seoul, 03722 Republic of Korea
- Systems Molecular Radiology at Yonsei, Seoul, 03722 Republic of Korea
- Brain Korea 21 plus Project for Medical Science, Yonsei University College of Medicine, Seoul, 03722 Republic of Korea
| | - Jaemoon Yang
- Department of Radiology, Yonsei University College of Medicine, Seoul, 03722 Republic of Korea
- Systems Molecular Radiology at Yonsei, Seoul, 03722 Republic of Korea
- Brain Korea 21 plus Project for Medical Science, Yonsei University College of Medicine, Seoul, 03722 Republic of Korea
- YUHS-KRIBB Medical Convergence Research Center, Yonsei University, Seoul, 03722 Republic of Korea
- Severance Biomedical Science Institute, Seoul, 03722 Republic of Korea
| | - Jin-Suck Suh
- Department of Radiology, Yonsei University College of Medicine, Seoul, 03722 Republic of Korea
- Brain Korea 21 plus Project for Medical Science, Yonsei University College of Medicine, Seoul, 03722 Republic of Korea
- YUHS-KRIBB Medical Convergence Research Center, Yonsei University, Seoul, 03722 Republic of Korea
- Severance Biomedical Science Institute, Seoul, 03722 Republic of Korea
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Patient-Derived Xenograft Models for Endometrial Cancer Research. Int J Mol Sci 2018; 19:ijms19082431. [PMID: 30126113 PMCID: PMC6121639 DOI: 10.3390/ijms19082431] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2018] [Revised: 08/03/2018] [Accepted: 08/13/2018] [Indexed: 12/21/2022] Open
Abstract
Endometrial cancer (EC) is the most common malignancy of the genital tract among women in developed countries. Recently, a molecular classification of EC has been performed providing a system that, in conjunction with histological observations, reliably improves EC classification and enhances patient management. Patient-derived xenograft models (PDX) represent nowadays a promising tool for translational research, since they closely resemble patient tumour features and retain molecular and histological features. In EC, PDX models have already been used, mainly as an individualized approach to evaluate the efficacy of novel therapies and to identify treatment-response biomarkers; however, their uses in more global or holistic approaches are still missing. As a collaborative effort within the ENITEC network, here we describe one of the most extensive EC PDX cohorts developed from primary tumour and metastasis covering all EC subtypes. Our models are histologically and molecularly characterized and represent an excellent reservoir of EC tumour samples for translational research. This review compiles the information on current methods of EC PDX generation and their utility and provides new perspectives for the exploitation of these valuable tools in order to increase the success ratio for translating results to clinical practice.
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Microdosing, isotopic labeling, radiotracers and metabolomics: relevance in drug discovery, development and safety. Bioanalysis 2017; 9:1913-1933. [PMID: 29171759 DOI: 10.4155/bio-2017-0137] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
This review discusses the use of stable (13C, 2D) or radioactive isotopes (14C, 11C, 18F, 131I, 64Cu, 68Ga) incorporated into the molecular structure of new drug entities for the purpose of pharmacokinetic or -dynamic studies. Metabolite in safety testing requires the administration of pharmacologically active doses. In such studies, radiotracers find application mainly in preclinical animal investigations, whereby LC-MS/MS is used to identify metabolite structure and drug-related effects. In contrast, first-in-human metabolite studies have to be carried out at nonpharmacological doses not exceeding 100 μg (microdose), which is generally too low for metabolite detection by LC-MS/MS. This short-coming can be overcome by specific radio- or isotopic labeling of the drug of interest and measurements using accelerator mass spectroscopy, single-photon emission computed tomography and positron emission tomography. Such combined radioisotope-based approaches permit Phase 0, first-in-human metabolite study.
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Esquinas PL, Rodríguez-Rodríguez C, Carlos De La Vega J, Bokharaei M, Saatchi K, Shirmohammad M, Häfeli UO, Sossi V, Celler A. 188Re image performance assessment using small animal multi-pinhole SPECT/PET/CT system. Phys Med 2017; 33:26-37. [DOI: 10.1016/j.ejmp.2016.11.105] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Revised: 10/10/2016] [Accepted: 11/14/2016] [Indexed: 02/08/2023] Open
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Longitudinal imaging of the ageing mouse. Mech Ageing Dev 2016; 160:93-116. [PMID: 27530773 DOI: 10.1016/j.mad.2016.08.001] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Revised: 07/30/2016] [Accepted: 08/04/2016] [Indexed: 12/13/2022]
Abstract
Several non-invasive imaging techniques are used to investigate the effect of pathologies and treatments over time in mouse models. Each preclinical in vivo technique provides longitudinal and quantitative measurements of changes in tissues and organs, which are fundamental for the evaluation of alterations in phenotype due to pathologies, interventions and treatments. However, it is still unclear how these imaging modalities can be used to study ageing with mice models. Almost all age related pathologies in mice such as osteoporosis, arthritis, diabetes, cancer, thrombi, dementia, to name a few, can be imaged in vivo by at least one longitudinal imaging modality. These measurements are the basis for quantification of treatment effects in the development phase of a novel treatment prior to its clinical testing. Furthermore, the non-invasive nature of such investigations allows the assessment of different tissue and organ phenotypes in the same animal and over time, providing the opportunity to study the dysfunction of multiple tissues associated with the ageing process. This review paper aims to provide an overview of the applications of the most commonly used in vivo imaging modalities used in mouse studies: micro-computed-tomography, preclinical magnetic-resonance-imaging, preclinical positron-emission-tomography, preclinical single photon emission computed tomography, ultrasound, intravital microscopy, and whole body optical imaging.
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