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Bahadorzadeh B, Faghihi R, Sina S, Aghaz A, Rahmim A, Reza Ay M. Design and implementation of continuous bed motion (CBM) in Xtrim preclinical PET scanner for whole-body Imaging: MC simulation and experimental measurements. Phys Med 2024; 123:103395. [PMID: 38843650 DOI: 10.1016/j.ejmp.2024.103395] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 05/09/2024] [Accepted: 06/01/2024] [Indexed: 07/13/2024] Open
Abstract
PURPOSE Preclinical PET scanners often have limited axial field-of-view for whole-body (WB) scanning of the small-animal. Step-and-shoot(S&S) acquisition mode requires multiple bed positions (BPs) to cover the scan length. Alternatively, in Continuous Bed Motion(CBM) mode, data acquisition is performed while the bed is continuously moving. In this study, to reduce acquisition time and enhance image quality, the CBM acquisition protocol was optimized and implemented on the Xtrim-PET preclinical scanner for WB imaging. METHODS The over-scan percentage(OS%) in CBM mode was optimized by Monte Carlo simulation. Bed movement speed was optimized considering ranges from 0.1 to 2.0 mm s-1, and absolute system sensitivities with the optimal OS% were calculated. The performance of the scanner in CBM mode was measured, and compared with S&S mode based on the NEMA-NU4 standard. RESULTS The optimal trade-off between absolute sensitivity and uniformity of sensitivity profile was achieved at OS-50 %. In comparison to S&S mode with maximum ring differences (MRD) of 9 and 23, the calculated equivalent speeds in CBM(OS-50 %) mode were 0.3 and 0.14 mm s-1, respectively. In terms of data acquisition with equal sensitivity in both CBM(OS-50 %) and S&S(MRD-9) modes, the total scan time in CBM mode decreased by 25.9 %, 47.7 %, 54.7 %, and 58.2 % for scan lengths of 1 to 4 BPs, respectively. CONCLUSION The CBM mode enhances WB PET scans for small-animals, offering rapid data acquisition, high system sensitivity, and uniform axial sensitivity, leading to improved image quality. Its efficiency and customizable scan length and bed speed make it a superior alternative.
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Affiliation(s)
- Bahador Bahadorzadeh
- Nuclear Engineering Department, School of Mechanical Engineering, Shiraz University, Shiraz, Iran; Research Center for Molecular and Cellular Imaging (RCMCI), Advanced Medical Technologies and Equipment Institute (AMTEI), Tehran University of Medical Sciences, Tehran, Iran
| | - Reza Faghihi
- Nuclear Engineering Department, School of Mechanical Engineering, Shiraz University, Shiraz, Iran; Radiation Research Center (RRC), Shiraz University, Shiraz, Iran.
| | - Sedigheh Sina
- Nuclear Engineering Department, School of Mechanical Engineering, Shiraz University, Shiraz, Iran; Radiation Research Center (RRC), Shiraz University, Shiraz, Iran
| | - Ahdiyeh Aghaz
- Radiation Application Research School, Nuclear Science and Technology Research Institute, Tehran, Iran
| | - Arman Rahmim
- Departments of Radiology and Physics Vancouver, The University of British Columbia, Vancouver, Canada; Department of Integrative Oncology, BC Cancer Research Institute, Vancouver, Canada
| | - Mohammad Reza Ay
- Research Center for Molecular and Cellular Imaging (RCMCI), Advanced Medical Technologies and Equipment Institute (AMTEI), Tehran University of Medical Sciences, Tehran, Iran; Department of Medical Physics and Biomedical Engineering, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
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2
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Azarafrouz F, Farhangian M, Chavoshinezhad S, Dargahi S, Nassiri-Asl M, Dargahi L. Interferon beta attenuates recognition memory impairment and improves brain glucose uptake in a rat model of Alzheimer's disease: Involvement of mitochondrial biogenesis and PI3K pathway. Neuropeptides 2022; 95:102262. [PMID: 35709657 DOI: 10.1016/j.npep.2022.102262] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 05/10/2022] [Accepted: 05/30/2022] [Indexed: 11/15/2022]
Abstract
Interferon beta (IFNβ) is a cytokine with anti-apoptotic and anti-inflammatory properties, and its beneficial effects on Alzheimer's disease (AD) have been recently shown. The alterations in cerebral glucose uptake are closely linked to memory deficit and AD progression. The current study was designed to determine if IFNβ can improve recognition memory and brain glucose uptake in a rat model of AD. The lentiviruses expressing mutant human amyloid precursor protein were injected bilaterally to the rat hippocampus. From day 23 after virus injection, rats were intranasally treated with recombinant IFNβ protein (68,000 IU/rat) every other day until day 50. Recognition memory performance was evaluated by novel object recognition test on days 46-49. The 18F-2- fluoro-deoxy-d-glucose positron emission tomography (18F-FDG-PET) was used to determine changes in brain glucose metabolism on day 50. The expression of the PI3K/Akt pathway components, neurotrophins and mitochondrial biogenesis factors were also measured by qPCR in the hippocampus. Our results showed that IFNβ treatment improves recognition memory performance in parallel with increased glucose uptake and neuronal survival in the hippocampus of the AD rats. The neuroprotective effect of IFNβ could be attributed, at least partly, to activation of PI3K-Akt-mTOR signaling pathway, increased expression of NGF, and mitochondrial biogenesis. Taken together, our findings suggest the therapeutic potential of IFNβ for AD.
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Affiliation(s)
- Forouzan Azarafrouz
- Neuroscience Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mohsen Farhangian
- Neuroscience Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Sara Chavoshinezhad
- Cellular and Molecular Research Center, Research Institute for Health Development, Kurdistan University of Medical Sciences, Sanandaj, Iran.
| | - Saina Dargahi
- Student Research Committee, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Marjan Nassiri-Asl
- Department of Pharmacology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran; Neurobiology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Leila Dargahi
- Neuroscience Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
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Ribeiro FM, Correia PMM, Santos AC, Veloso JFCA. A guideline proposal for mice preparation and care in 18F-FDG PET imaging. EJNMMI Res 2022; 12:49. [PMID: 35962869 PMCID: PMC9375789 DOI: 10.1186/s13550-022-00921-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Accepted: 07/31/2022] [Indexed: 11/28/2022] Open
Abstract
The experimental outcomes of small-animal positron emission tomography (PET) imaging with 18F-labelled fluorodeoxyglucose (18F-FDG) can be particularly compromised by animal preparation and care. Several works intend to improve research reporting and amplify the quality and reliability of published research. Though these works provide valuable information to plan and conduct animal studies, manuscripts describe different methodologies—standardization does not exist. Consequently, the variation in details reported can explain the difference in the experimental results found in the literature. Additionally, the resources and guidelines defining protocols for small-animal imaging are scarce, making it difficult for researchers to obtain and compare accurate and reproducible data. Considering the selection of suitable procedures key to ensure animal welfare and research improvement, this paper aims to prepare the way for a future guideline on mice preparation and care for PET imaging with 18F-FDG. For this purpose, a global standard protocol was created based on recommendations and good practices described in relevant literature.
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Affiliation(s)
- F M Ribeiro
- Institute for Nanostructures, Nanomodelling and Nanofabrication (i3N), Department of Physics, University of Aveiro (DFis-UA), 3810-193, Aveiro, Portugal.
| | - P M M Correia
- Institute for Nanostructures, Nanomodelling and Nanofabrication (i3N), Department of Physics, University of Aveiro (DFis-UA), 3810-193, Aveiro, Portugal
| | - A C Santos
- Institute for Clinical and Biomedical Research (iCBR), Faculty of Medicine of the University of Coimbra (FMUC), Area of Environment Genetics and Oncobiology (CIMAGO), Center for Innovative Biomedicine and Biotechnology (CIBB), 3000-548, Coimbra, Portugal
| | - J F C A Veloso
- Institute for Nanostructures, Nanomodelling and Nanofabrication (i3N), Department of Physics, University of Aveiro (DFis-UA), 3810-193, Aveiro, Portugal
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4
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Fooladi M, Shirazi A, Sheikhzadeh P, Amirrashedi M, Ghahramani F, Cheki M, Khoobi M. Investigating the attenuating effect of telmisartan against radiation-induced intestinal injury using 18F-FDG micro-PET imaging. Int J Radiat Biol 2022; 99:446-458. [PMID: 35930426 DOI: 10.1080/09553002.2022.2110295] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
BACKGROUND AND OBJECTIVE This study was aimed to investigate the ability of 18F-Fluro-deoxy-glucose (18F-FDG)-based micro-positron emission tomography (microPET) imaging to evaluate the efficacy of telmisartan, a highly selective angiotensin II receptor antagonist (ARA), in intestinal tissue recovery process after in vivo irradiation. METHODS Male Balb/c mice were randomly divided into four groups of control, telmisartan, irradiation, and telmisartan + irradiation. A solution of telmisartan in phosphate-buffered saline (PBS) was administered orally at 12 mg/kg body weight for seven consecutive days prior to whole body exposing to a single sub-lethal dose of 5 Gy X-rays. The mice were imaged using 18F-FDG microPET at 9 and 30 days post-irradiation. The 18F-FDG uptake in jejunum was determined according to the mean standardized uptake value (SUVmean) index. Tissues were also processed in similar time points for histological analysis. RESULTS The 18F-FDG microPET imaging confirmed the efficacy of telmisartan as a potent attenuating agent for ionizing radiation-induced injury of intestine in mice model. The results were also in line with the histological analysis indicating that pretreatment with telmisartan reduced damage to the villi, crypts, and intestinal mucosa compared with irradiated and non-treated group from day 9 to 30 after irradiation. CONCLUSION The results revealed that 18F-FDG microPET imaging could be a good candidate to replace time-consuming and invasive biological techniques for screening of radioprotective agents. These findings were also confirmed by histological examinations which indicated that telmisartan can effectively attenuates radiation injury caused by ionizing-irradiation.
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Affiliation(s)
- Masoomeh Fooladi
- Department of Medical Physics and Biomedical Engineering, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Alireza Shirazi
- Department of Medical Physics and Biomedical Engineering, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Peyman Sheikhzadeh
- Department of Nuclear Medicine, Imam Khomeini Hospital Complex, Tehran University of Medical Sciences, Tehran, Iran
| | - Mahsa Amirrashedi
- Department of Medical Physics and Biomedical Engineering, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran.,Research Center for Molecular and Cellular Imaging, Tehran University of Medical Sciences, Tehran, Iran
| | - Fatemeh Ghahramani
- Radiotherapy-Oncology Center, Yas Hospital, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Mohsen Cheki
- Department of Medical Imaging and Radiation Sciences, Faculty of Paramedicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Mehdi Khoobi
- Biomaterials Group, Pharmaceutical Sciences Research Center, The Institute of Pharmaceutical Sciences (TIPS), Tehran University of Medical Sciences, Tehran, Iran.,Department of Radiopharmacy, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran
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Performance Evaluation of a PET of 7T Bruker Micro-PET/MR Based on NEMA NU 4-2008 Standards. ELECTRONICS 2022. [DOI: 10.3390/electronics11142194] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Purpose: This study aimed to measure the performance evaluation of the Bruker sequential micro-positron emission tomography/magnetic resonance imaging (PET/MRI) scanner by following National Electrical Manufacturers Association (NEMA) NU 4-2008 standards’ protocol. The system consists of a high-performance silicon photomultiplier (SiPM) advanced technology detector and a continuous lutetium-yttrium oxyorthosilicate (LYSO) crystal. Methods: A 22Na (sodium-22) point source was utilized to assess the spatial resolution and system sensitivity, and the Micro-PET scatter phantom measurements were conducted to measure count rate measurements and scatter fractions (SF). A mouse-like Micro-PET image quality (IQ) phantom was utilized as a model to analyze the uniformity, recovery coefficient (RC), and spillover ratio (SOR). A small animal PET/MRI imaging study was performed in a rat. Results: We calculated the spatial resolutions of filtered back-projection (FBP), and used 3D-MLEM to reconstruct PET images at the axial center and ¼ of the axial field of view (FOV) in axial, radial, and tangential directions. The best observed spatial resolutions in both reconstructed images were obtained in the tangential direction, and the values were 0.80 mm in 3D-MLEM and 0.94 mm in FBP. The peak noise equivalent count rate (NECR) in the 358–664 keV energy window was 477.30 kcps at 95.83 MBq and 774.45 kcps at 103.6 MBq for rat and mouse-sized scatter phantoms, respectively. The rat and mouse-sized phantoms scatter fractions (SF) were 14.2% and 6.9%, respectively. Conclusions: According to our results, the performance characteristics of the scanner are high sensitivity, good spatial resolution, low scatter fraction, and good IQ, indicating that it is suitable for preclinical imaging studies.
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Khateri P, Lustermann W, Ritzer C, Tsoumpas C, Dissertori G. NEMA characterization of the SAFIR prototype PET insert. EJNMMI Phys 2022; 9:42. [PMID: 35695989 PMCID: PMC9192892 DOI: 10.1186/s40658-022-00454-2] [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: 04/26/2021] [Accepted: 03/28/2022] [Indexed: 11/29/2022] Open
Abstract
Background The SAFIR prototype insert is a preclinical Positron Emission Tomography (PET) scanner built to acquire dynamic images simultaneously with a 7 T Bruker Magnetic Resonance Imaging (MRI) scanner. The insert is designed to perform with an excellent coincidence resolving time of 194 ps Full Width Half Maximum (FWHM) and an energy resolution of 13.8% FWHM. These properties enable it to acquire precise quantitative images at activities as high as 500 MBq suitable for studying fast biological processes within short time frames (< 5 s). In this study, the performance of the SAFIR prototype insert is evaluated according to the NEMA NU 4-2008 standard while the insert is inside the MRI without acquiring MRI data. Results Applying an energy window of 391–601 keV and a coincidence time window of 500 ps the following results are achieved. The average spatial resolution at 5 mm radial offset is 2.6 mm FWHM when using the Filtered Backprojection 3D Reprojection (FBP3DRP) reconstruction method, improving to 1.2 mm when using the Maximum Likelihood Expectation Maximization (MLEM) method. The peak sensitivity at the center of the scanner is 1.06%. The Noise Equivalent count Rate (NECR) is 799 kcps at the highest measured activity of 537 MBq for the mouse phantom and 121 kcps at the highest measured activity of 624 MBq for the rat phantom. The NECR peak is not yet reached for any of the measurements. The scatter fractions are 10.9% and 17.8% for the mouse and rat phantoms, respectively. The uniform region of the image quality phantom has a 3.0% STD, with a 4.6% deviation from the expected number of counts per voxel. The spill-over ratios for the water and air chambers are 0.18 and 0.17, respectively. Conclusions The results satisfy all the requirements initially considered for the insert, proving that the SAFIR prototype insert can obtain dynamic images of small rodents at high activities (\documentclass[12pt]{minimal}
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\begin{document}$$\sim$$\end{document}∼ 500 MBq) with a high sensitivity and an excellent count-rate performance.
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Affiliation(s)
- Parisa Khateri
- Institute for Particle Physics and Astrophysics, ETH Zürich, Zürich, Switzerland.
| | - Werner Lustermann
- Institute for Particle Physics and Astrophysics, ETH Zürich, Zürich, Switzerland
| | - Christian Ritzer
- Institute for Particle Physics and Astrophysics, ETH Zürich, Zürich, Switzerland
| | - Charalampos Tsoumpas
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, Groningen, The Netherlands
| | - Günther Dissertori
- Institute for Particle Physics and Astrophysics, ETH Zürich, Zürich, Switzerland
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7
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Shamaeizadeh N, Varshosaz J, Mirian M, Aliomrani M. Glutathione targeted tragacanthic acid-chitosan as a non-viral vector for brain delivery of miRNA-219a-5P: An in vitro/in vivo study. Int J Biol Macromol 2022; 200:543-556. [DOI: 10.1016/j.ijbiomac.2022.01.100] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Revised: 01/04/2022] [Accepted: 01/15/2022] [Indexed: 12/25/2022]
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8
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Fysikopoulos E, Rouchota M, Georgiou M, Sfyris C, Cheimarios N, Sarpaki S, Kostopoulos S, Glotsos D, Larimer B, Hunter C, Lapi S, Houson H, Massicano AVF, Sorace A, Lamprou E, Loudos G. β-eye: A benchtop system for in vivo molecular screening of labeled compounds. Appl Radiat Isot 2021; 180:110034. [PMID: 34894480 DOI: 10.1016/j.apradiso.2021.110034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 10/26/2021] [Accepted: 11/16/2021] [Indexed: 11/17/2022]
Abstract
Preclinical nuclear molecular imaging speeds up the mean time from synthesis to market, in drug development process. Commercial imaging systems have in general high cost, require high-cost service contracts, special facilities and trained staff. In the current work, we present β-eye, a benchtop system for in vivo molecular screening of labeled compounds with Positron Emission Tomography (PET) isotopes. The developed system is based on a dual-head geometry, offering simplicity and decreased cost. The goal of the design is to provide 2D, real-time radionuclide images of mice, allowing the recording of fast frames and thus perform fast kinetic studies, with spatial resolution of ∼2 mm. Performance evaluation demonstrates the ability of β-eye to provide quantitative results for injected activities lower than 1.5 MBq, which is adequate for pharmacodynamic studies in small mice.
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Affiliation(s)
- E Fysikopoulos
- BIOEMTECH, Lefkippos Attica Technology Park - N.C.S.R Demokritos, Greece; Biomedical Engineering Department, University of West Attica, Athens, Greece.
| | - M Rouchota
- BIOEMTECH, Lefkippos Attica Technology Park - N.C.S.R Demokritos, Greece; Biomedical Engineering Department, University of West Attica, Athens, Greece
| | - M Georgiou
- BIOEMTECH, Lefkippos Attica Technology Park - N.C.S.R Demokritos, Greece
| | - C Sfyris
- BIOEMTECH, Lefkippos Attica Technology Park - N.C.S.R Demokritos, Greece
| | - N Cheimarios
- BIOEMTECH, Lefkippos Attica Technology Park - N.C.S.R Demokritos, Greece
| | - S Sarpaki
- BIOEMTECH, Lefkippos Attica Technology Park - N.C.S.R Demokritos, Greece
| | - S Kostopoulos
- Biomedical Engineering Department, University of West Attica, Athens, Greece
| | - D Glotsos
- Biomedical Engineering Department, University of West Attica, Athens, Greece
| | - B Larimer
- Small Animal Imaging Facility, Department of Radiology, The University of Alabama at Birmingham, United States of America
| | - C Hunter
- Small Animal Imaging Facility, Department of Radiology, The University of Alabama at Birmingham, United States of America
| | - S Lapi
- Small Animal Imaging Facility, Department of Radiology, The University of Alabama at Birmingham, United States of America
| | - H Houson
- Small Animal Imaging Facility, Department of Radiology, The University of Alabama at Birmingham, United States of America
| | - A V F Massicano
- Small Animal Imaging Facility, Department of Radiology, The University of Alabama at Birmingham, United States of America
| | - A Sorace
- Small Animal Imaging Facility, Department of Radiology, The University of Alabama at Birmingham, United States of America
| | - E Lamprou
- BIOEMTECH, Lefkippos Attica Technology Park - N.C.S.R Demokritos, Greece
| | - G Loudos
- BIOEMTECH, Lefkippos Attica Technology Park - N.C.S.R Demokritos, Greece
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Amirrashedi M, Sarkar S, Mamizadeh H, Ghadiri H, Ghafarian P, Zaidi H, Ay MR. Leveraging deep neural networks to improve numerical and perceptual image quality in low-dose preclinical PET imaging. Comput Med Imaging Graph 2021; 94:102010. [PMID: 34784505 DOI: 10.1016/j.compmedimag.2021.102010] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 10/25/2021] [Accepted: 10/26/2021] [Indexed: 01/24/2023]
Abstract
The amount of radiotracer injected into laboratory animals is still the most daunting challenge facing translational PET studies. Since low-dose imaging is characterized by a higher level of noise, the quality of the reconstructed images leaves much to be desired. Being the most ubiquitous techniques in denoising applications, edge-aware denoising filters, and reconstruction-based techniques have drawn significant attention in low-count applications. However, for the last few years, much of the credit has gone to deep-learning (DL) methods, which provide more robust solutions to handle various conditions. Albeit being extensively explored in clinical studies, to the best of our knowledge, there is a lack of studies exploring the feasibility of DL-based image denoising in low-count small animal PET imaging. Therefore, herein, we investigated different DL frameworks to map low-dose small animal PET images to their full-dose equivalent with quality and visual similarity on a par with those of standard acquisition. The performance of the DL model was also compared to other well-established filters, including Gaussian smoothing, nonlocal means, and anisotropic diffusion. Visual inspection and quantitative assessment based on quality metrics proved the superior performance of the DL methods in low-count small animal PET studies, paving the way for a more detailed exploration of DL-assisted algorithms in this domain.
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Affiliation(s)
- Mahsa Amirrashedi
- Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences, Tehran, Iran; Research Center for Molecular and Cellular Imaging, Tehran University of Medical Sciences, Tehran, Iran.
| | - Saeed Sarkar
- Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences, Tehran, Iran; Research Center for Molecular and Cellular Imaging, Tehran University of Medical Sciences, Tehran, Iran.
| | - Hojjat Mamizadeh
- Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences, Tehran, Iran; Research Center for Molecular and Cellular Imaging, Tehran University of Medical Sciences, Tehran, Iran.
| | - Hossein Ghadiri
- Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences, Tehran, Iran; Research Center for Molecular and Cellular Imaging, Tehran University of Medical Sciences, Tehran, Iran.
| | - Pardis Ghafarian
- Chronic Respiratory Diseases Research Center, National Research Institute of Tuberculosis and Lung Diseases (NRITLD), Shahid Beheshti University of Medical Sciences, Tehran, Iran; PET/CT and Cyclotron Center, Masih Daneshvari Hospital, Shahid Beheshti University of Medical, Tehran, Iran.
| | - Habib Zaidi
- Division of Nuclear Medicine and Molecular Imaging, Geneva University Hospital, Geneva CH-1211, Switzerland; Geneva University Neurocenter, Geneva University, Geneva, Switzerland; Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, Netherlands; Department of Nuclear Medicine, University of Southern Denmark, Odense, Denmark.
| | - Mohammad Reza Ay
- Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences, Tehran, Iran; Research Center for Molecular and Cellular Imaging, Tehran University of Medical Sciences, Tehran, Iran.
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Liu Q, Li C, Liu J, Krish K, Fu X, Zhao J, Chen JC. Technical Note: Performance evaluation of a small-animal PET/CT system based on NEMA NU 4-2008 standards. Med Phys 2021; 48:5272-5282. [PMID: 34252215 DOI: 10.1002/mp.15088] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 04/01/2021] [Accepted: 06/22/2021] [Indexed: 11/06/2022] Open
Abstract
PURPOSE The MetisTM PET/CT is a self-developed, silicon photomultiplier (SiPM) detector-based, rodent PET/CT system. The objective of this study was to evaluate the performance of the system using the National Electrical Manufacturers Association (NEMA) NU 4-2008 standard protocol. METHODS Energy resolution, spatial resolution, sensitivity, scatter fraction (SF), noise-equivalent count rate (NECR), and image quality (IQ) characteristics were measured. A micro Derenzo phantom experiment was performed to evaluate the spatial resolution using three-dimensional ordered-subsets expectation maximization (3D-OSEM) and maximum likelihood expectation maximization (MLEM) reconstructed images. In addition, the CT imaging agent Ioverol 350 was mixed with fluorine-18 (18 F)-fluorodeoxyglucose (FDG) and then injected into the micro Derenzo phantom to evaluate the PET/CT imaging. In vivo PET/CT imaging studies were also conducted in a healthy mouse and rat using 18 F-FDG. RESULTS The mean energy resolution of the system was 15.3%. The tangential resolution was 0.82 mm full-width half-maximum (FWHM) at the center of the field of the view (FOV), and the radial and axial resolution were generally lower than 2.0 mm FWHM. The spatial resolution was significantly improved when using 3D-OSEM, especially the axial FWHM could be improved by up to about 57%. The system absolute sensitivity was 7.7% and 6.8% for an energy window of 200-750 and 350-750 keV respectively. The scatter fraction was 8.2% and 12.1% for the mouse- and rat-like phantom respectively. The peak NECR was 1343.72 kcps at 69 MBq and 640.32 kcps at 53 MBq for the mouse- and rat-like phantom respectively. The 1-mm fillable rod in the IQ phantom can be clearly observed. We can identify the 0.6-mm aperture of the micro Derenzo phantom image clearly using 3D-OSEM (10 subsets, 5 iterations). We also performed the fusion of the PET and CT images of the mouse and the brain imaging of the rat. CONCLUSIONS The results show that the system has the characteristics of high-resolution, high-sensitivity, and excellent IQ and is suitable for rodent imaging-based research.
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Affiliation(s)
- Qiong Liu
- School of Medical Imaging, Xuzhou Medical University, Jiangsu, China
| | - Chaofan Li
- School of Medical Information and Engineering, Xuzhou Medical University, Jiangsu, China
| | - Jiguo Liu
- Shandong Madic Technology Co., Ltd., Shandong, China
| | - Kishore Krish
- Department of Biomedical Imaging and Radiological Sciences, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Xinlei Fu
- Shandong Madic Technology Co., Ltd., Shandong, China
| | - Jie Zhao
- School of Medical Imaging, Xuzhou Medical University, Jiangsu, China
| | - Jyh-Cheng Chen
- School of Medical Imaging, Xuzhou Medical University, Jiangsu, China.,Department of Biomedical Imaging and Radiological Sciences, National Yang Ming Chiao Tung University, Taipei, Taiwan.,Department of Medical Imaging and Radiological Technology, Yuanpei University of Medical Technology, Hsinchu, Taiwan
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Yang Q, Wang X, Kuang Z, Zhang C, Yang Y, Du J. Evaluation of Two SiPM Arrays for Depth-Encoding PET Detectors Based on Dual-Ended Readout. IEEE TRANSACTIONS ON RADIATION AND PLASMA MEDICAL SCIENCES 2021. [DOI: 10.1109/trpms.2020.3008710] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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12
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Gaudin É, Thibaudeau C, Arpin L, Leroux JD, Toussaint M, Beaudoin JF, Cadorette J, Paillé M, Pepin CM, Koua K, Bouchard J, Viscogliosi N, Paulin C, Fontaine R, Lecomte R. Performance evaluation of the mouse version of the LabPET II PET scanner. Phys Med Biol 2021; 66:065019. [PMID: 33412542 DOI: 10.1088/1361-6560/abd952] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The LabPET II is a new positron emission tomography technology platform designed to achieve submillimetric spatial resolution imaging using fully pixelated avalanche photodiodes-based detectors and highly integrated parallel front-end processing electronics. The detector was designed as a generic building block to develop devices for preclinical imaging of small to mid-sized animals and for clinical imaging of the human brain. The aim of this work is to assess the physical characteristics and imaging performance of the mouse version of LabPET II scanner following the NEMA NU4-2008 standard and using high resolution phantoms and in vivo imaging applications. A reconstructed spatial resolution of 0.78 mm (0.5 μ l) is measured close to the center of the radial field of view. With an energy window of 350 650 keV, the system absolute sensitivity is 1.2% and its maximum noise equivalent count rate reaches 61.1 kcps at 117 MBq. Submillimetric spatial resolution is achieved in a hot spot phantom and tiny bone structures were resolved with unprecedented contrast in the mouse. These results provide convincing evidence of the capabilities of the LabPET II technology for biomolecular imaging in preclinical research.
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Affiliation(s)
- Émilie Gaudin
- Sherbrooke Molecular Imaging Center and Department of Nuclear Medicine and Radiobiology, Université de Sherbrooke, Sherbrooke, QC, Canada
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Yoshida E, Akamatsu G, Tashima H, Kamada K, Yoshikawa A, Yamaya T. First imaging demonstration of a crosshair light-sharing PET detector. Phys Med Biol 2021; 66:065013. [PMID: 33607635 DOI: 10.1088/1361-6560/abe839] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The crosshair light-sharing (CLS) PET detector is our original depth-of-interaction (DOI) detector, which is based on a single-ended readout scheme with quadrisected crystals comparable in size to a photo-sensor. In this work, we developed 32 CLS PET detectors, each of which consisted of a multi-pixel photon counter (MPPC) array and gadolinium fine aluminum garnet (GFAG) crystals, and we developed a benchtop prototype of a small animal size PET. Each GFAG crystal was 1.45 × 1.45 × 15 mm3. The MPPC had a surface area of 3.0 × 3.0 mm2. The benchtop prototype had two detector rings of 16 detector blocks. The ring diameter and axial field-of-view were 14.2 cm and 4.9 cm, respectively. The data acquisition system used was the PETsys silicon photomultiplier readout system. The continuous DOI information was binned into three DOI layers by applying a look-up-table to a 2D position histogram. Also, energy and timing information was corrected using DOI information. After the calibration procedure, the energy resolution and the coincidence time resolution were 14.6% and 531 ps, respectively. Imaging test results of a small rod phantom obtained by an iterative reconstruction method showed clear separation of 1.6 mm rods with the help of DOI information.
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Affiliation(s)
- Eiji Yoshida
- National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
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Courteau A, McGrath J, Walker PM, Pegg R, Martin G, Garipov R, Doughty P, Cochet A, Brunotte F, Vrigneaud JM. Performance Evaluation and Compatibility Studies of a Compact Preclinical Scanner for Simultaneous PET/MR Imaging at 7 Tesla. IEEE TRANSACTIONS ON MEDICAL IMAGING 2021; 40:205-217. [PMID: 32956042 DOI: 10.1109/tmi.2020.3024722] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
We present the design and performance of a new compact preclinical system combining positron emission tomography (PET) and magnetic resonance imaging (MRI) for simultaneous scans. The PET contains sixteen SiPM-based detector heads arranged in two octagons and covers an axial field of view (FOV) of 102.5 mm. Depth of interaction effects and detector's temperature variations are compensated by the system. The PET is integrated in a dry magnet operating at 7 T. PET and MRI characteristics were assessed complying with international standards and interferences between both subsystems during simultaneous scans were addressed. For the rat size phantom, the peak noise equivalent count rates (NECR) were 96.4 kcps at 30.2 MBq and 132.3 kcps at 28.4 MBq respectively with and without RF coil. For mouse, the peak NECR was 300.0 kcps at 34.5 MBq and 426.9 kcps at 34.3 MBq respectively with and without coil. At the axial centre of the FOV, spatial resolutions expressed as full width at half maximum / full width at tenth maximum (FWHM/FWTM) ranged from 1.69/3.19 mm to 2.39/4.87 mm. The peak absolute sensitivity obtained with a 250-750 keV energy window was 7.5% with coil and 7.9% without coil. Spill over ratios of the NEMA NU4-2008 image quality (NEMA-IQ) phantom ranged from 0.25 to 0.96 and the percentage of non-uniformity was 5.7%. The image count versus activity was linear up to 40 MBq. The principal magnetic field variation was 0.03 ppm/mm over 40 mm. The qualitative and quantitative aspects of data were preserved during simultaneous scans.
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Sanaat A, Ashrafi-Belgabad A, Zaidi H. Polaroid-PET: a PET scanner with detectors fitted with Polaroid for filtering unpolarized optical photons-a Monte Carlo simulation study. Phys Med Biol 2020; 65:235044. [PMID: 33263320 DOI: 10.1088/1361-6560/abaeb8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
We propose and evaluate the performance of an improved preclinical positron emission tomography (PET) scanner design, referred to as Polaroid-PET, consisting of a detector equipped with a layer of horizontal Polaroid to filter scintillation photons with vertical polarization. This makes it possible to improve the spatial resolution of PET scanners based on monolithic crystals. First, a detector module based on a lutetium-yttrium orthosilicate monolithic crystal with 10 mm thickness and silicon photomultipliers (SiPMs) was implemented in the GEANT4 Monte Carlo toolkit. Subsequently, a layer of Polaroid was inserted between the crystal and the SiPMs. Two preclinical PET scanners based on ten detector modules with and without Polaroid were simulated. The performance of the proposed detector modules and corresponding PET scanner for the two configurations (with and without Polaroid) was assessed using standard performance parameters, including spatial resolution, sensitivity, optical photon ratio detected for positioning, and image quality. The detector module fitted with Polaroid led to higher spatial resolution (1.05 mm FWHM) in comparison with a detector without Polaroid (1.30 mm FHWM) for a point source located at the center of the detector module. From 100% of optical photons produced in the scintillator crystal, 65% and 66% were used for positioning in the detectors without and with Polaroid, respectively. Polaroid-PET resulted in higher axial spatial resolution (0.83 mm FWHM) compared to the scanner without Polaroid (1.01 mm FWHM) for a point source at the center of the field of view (CFOV). The absolute sensitivity at the CFOV was 4.37% and 4.31% for regular and Polaroid-PET, respectively. Planar images of a grid phantom demonstrated the potential of the detector with a Polaroid in distinguishing point sources located at close distances. Our results indicated that Polaroid-PET may improve spatial resolution by filtering the reflected optical photons according to their polarization state, while retaining the high sensitivity expected with monolithic crystal detector blocks.
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Affiliation(s)
- Amirhossein Sanaat
- Division of Nuclear Medicine and Molecular Imaging, Geneva University Hospital, Geneva 1211, Switzerland
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Abstract
In the light of ever-increasing demands for PET scanner with better resolvability, higher sensitivity and wide accessibility for noninvasive screening of small structures and physiological processes in laboratory rodents, several dedicated PET scanners were developed and evaluated. Understanding conceptual design constraints pros and cons of different configurations and impact of the major components will be helpful to further establish the crucial role of these miniaturized systems in a broad spectrum of modern research. Hence, a comprehensive review of preclinical PET scanners developed till early 2020 with particular emphasis on innovations in instrumentation and geometrical designs is provided.
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Affiliation(s)
- Mahsa Amirrashedi
- Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences, Tehran, Iran; Research Center for Molecular and Cellular Imaging, Tehran University of Medical Sciences, Tehran, Iran
| | - Habib Zaidi
- Division of Nuclear Medicine and Molecular Imaging, Geneva University Hospital, Geneva CH-1211, Switzerland; Geneva University Neurocenter, Geneva University, Geneva CH-1205, Switzerland; Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen 9700 RB, Netherlands; Department of Nuclear Medicine, University of Southern Denmark, Odense 500, Denmark
| | - Mohammad Reza Ay
- Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences, Tehran, Iran; Research Center for Molecular and Cellular Imaging, Tehran University of Medical Sciences, Tehran, Iran.
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Depth of Interaction Estimation in a Preclinical PET Scanner Equipped with Monolithic Crystals Coupled to SiPMs Using a Deep Neural Network. APPLIED SCIENCES-BASEL 2020. [DOI: 10.3390/app10144753] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The scintillation light distribution produced by photodetectors in positron emission tomography (PET) provides the depth of interaction (DOI) information required for high-resolution imaging. The goal of positioning techniques is to reverse the photodetector signal’s pattern map to the coordinates of the incident photon energy position. By considering the DOI information, monolithic crystals offer good spatial, energy, and timing resolution along with high sensitivity. In this work, a supervised deep neural network was used for the approximation of DOI and to assess through Monte Carlo (MC) simulations the performance on a small-animal PET scanner consisting of ten 50 × 50 × 10 mm3 continuous Lutetium-Yttrium Oxyorthosilicate doped with Cerium (LYSO: Ce) crystals and 12 × 12 silicon photomultiplier (SiPM) arrays. The scintillation position was predicted by a multilayer perceptron neural network with 256 units and 4 layers whose inputs were the number of fired pixels on the SiPM plane and the total deposited energy. A GEANT4 MC code was used to generate training and test datasets by altering the photons’ incident position, energy, and direction, as well as readout of the photodetector output. The calculated spatial resolutions in the X-Y plane and along the Z-axis were 0.96 and 1.02 mm, respectively. Our results demonstrated that using a multilayer perceptron (MLP)-based positioning algorithm in the detector modules, constituting the PET scanner, enhances the spatial resolution by approximately 18% while the absolute sensitivity remains constant. The proposed algorithm proved its ability to predict the DOI for depth under 7 mm with an error below 8.7%.
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Sanaat A, Arabi H, Reza Ay M, Zaidi H. Novel preclinical PET geometrical concept using a monolithic scintillator crystal offering concurrent enhancement in spatial resolution and detection sensitivity: a simulation study. ACTA ACUST UNITED AC 2020; 65:045013. [DOI: 10.1088/1361-6560/ab63ef] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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