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Zan K, Duan Y, Zhao M, Li H, Cui X, Chai L, Cheng Z. Performance of the Iterative OSEM and HYPER Algorithm for Total-body PET at SUVmax with a Low 18F-FDG Activity, a Short Acquisition Time and Small Lesions. Curr Med Imaging 2024:CMIR-EPUB-139356. [PMID: 38532604 DOI: 10.2174/0115734056274225240109112413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2023] [Revised: 12/16/2023] [Accepted: 12/30/2023] [Indexed: 03/28/2024]
Abstract
OBJECTIVE The primary objective of this comparative investigation was to examine the qualitative attributes of image reconstructions utilizing two distinct algorithms, namely OSEM and HYPER Iterative, in total-body 18F- FDG PET/CT under various acquisition durations and injection activities. METHODS An initial assessment was executed using a NEMA phantom to compare image quality engendered by OSEM and HYPER Iterative algorithms. Parameters such as BV, COV, and CRC were meticulously evaluated. Subsequently, a prospective cohort study was conducted on 50 patients, employing both reconstruction algorithms. The study was compartmentalized into distinct acquisition time and dosage groups. Lesions were further categorized into three size-based groups. Quantifiable metrics including SD of noise, SUVmax, SNR, and TBR were computed. Additionally, the differences in values, namely ΔSUVmax, ΔTBR, %ΔSUVmax, %ΔSD, and %ΔSNR, between OSEM and HYPER Iterative algorithms were also calculated. RESULTS The HYPER Iterative algorithm showed reduced BV and COV compared to OSEM in the phantom study, with constant acquisition time. In the clinical study, lesion SUVmax, TBR, and SNR were significantly elevated in images reconstructed using the HYPER Iterative algorithm in comparison to those generated by OSEM (p < 0.001). Furthermore, an amplified increase in SUVmax was predominantly discernible in lesions with dimensions less than 10 mm. Metrics such as %ΔSNR and %ΔSD in HYPER Iterative exhibited improvements correlating with reduced acquisition times and dosages, wherein a more pronounced degree of enhancement was observable in both ΔSUVmax and ΔTBR. CONCLUSION The HYPER Iterative algorithm significantly improves SUVmax and reduces noise level, with particular efficacy in lesions measuring ≤ 10 mm and under conditions of abbreviated acquisition times and lower dosages.
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Affiliation(s)
- Keyu Zan
- Department of Nuclear Medicine, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Jinan, China
| | - Yanhua Duan
- Department of Nuclear Medicine, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Jinan, China
| | - Minjie Zhao
- Department of Nuclear Medicine, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Jinan, China
| | - Hui Li
- Department of Nuclear Medicine, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Jinan, China
| | - Xiao Cui
- Department of Nuclear Medicine, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Jinan, China
| | - Leiying Chai
- Department of Nuclear Medicine, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Jinan, China
| | - Zhaoping Cheng
- Department of Nuclear Medicine, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Jinan, China
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Singh MK, Agarwal KK, Vishwakarma M, Patel H. Technical NEMA NU2-2018 Performance Assessment of Time-of-Flight-Integrated Digital PET-CT System. World J Nucl Med 2024; 23:10-16. [PMID: 38595839 PMCID: PMC11001449 DOI: 10.1055/s-0044-1778709] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/11/2024] Open
Abstract
Aim The objective of this study includes the NEMA (National Electrical Manufacturer Association) NU2-2018 performance evaluation of the uMIvista PET-CT (positron emission tomography-computed tomography) system. Methods The latest NEMA NU2-2018 guidelines have been followed for the evaluation of performance parameters of this PET-CT scanner: axial, tangential, and radial spatial resolution, sensitivity, counting losses, scatter, randomness, random and counting loss correction, image quality, time and energy resolution, image uniformity, and image registration alignment post installation of country first uMIvista PET-CT. Results The measured NEMA sensitivity of the uMIvista PET scanner was 12.053 cps/kBq. The spatial resolutions of the PET were measured as tangential, radial, and transaxial spatial resolutions at 10 mm, with 3.01 mm, 2.95 mm, and 2.93 mm, respectively; at 100 mm, with 3.17 mm, 3.42 mm, and 3.05 mm, respectively; and at 200 mm, with 3.65 mm, 4.54 mm, and 3.17 mm, respectively, at full-width half-maximum (FWHM); while at full-width tenths-maximum (FWTM), the values at 10 mm were 5.79 mm, 5.57 mm, and 5.69 mm, respectively, and at 100 mm were 5.59 mm, 5.96 mm, and 5.91 mm, respectively. The measured time-of-flight (TOF) timing resolution was 302.294 ps and the measured energy resolution was 11.76% with FWHM and FWTM. Conclusion The NEMA NU2-2018 performances of this TOF-integrated digital PET-CT system are extremely good in all parameters.
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Affiliation(s)
- Manoj Kumar Singh
- Medikabazaar, Technopolis Knowledge Park, Mumbai, Maharashtra, India
| | | | | | - Hemant Patel
- Gujarat Imaging Centre, Ahmedabad, Gujarat, India
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Hinz C, Jahnke S, Metzner R, Pflugfelder D, Scheins J, Streun M, Koller R. Setup and characterisation according to NEMA NU 4 of the phenoPET scanner, a PET system dedicated for plant sciences. Phys Med Biol 2024; 69:055019. [PMID: 38271724 DOI: 10.1088/1361-6560/ad22a2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Accepted: 01/25/2024] [Indexed: 01/27/2024]
Abstract
Objective.ThephenoPET system is a plant dedicated positron emission tomography (PET) scanner consisting of fully digital photo multipliers with lutetium-yttrium oxyorthosilicate crystals and located inside a custom climate chamber. Here, we present the setup ofphenoPET, its data processing and image reconstruction together with its performance.Approach.The performance characterization follows the national electrical manufacturers association (NEMA) standard for small animal PET systems with a number of adoptions due to the vertical oriented bore of a PET for plant sciences. In addition temperature stability and spatial resolution with a hot rod phantom are addressed.Main results.The spatial resolution for a22Na point source at a radial distance of 5 mm to the center of the field-of-view (FOV) is 1.45 mm, 0.82 mm and 1.88 mm with filtered back projection in radial, tangential and axial direction, respectively. A hot rod phantom with18F gives a spatial resolution of up to 1.6 mm. The peak noise-equivalent count rates are 550 kcps @ 35.08 MBq, 308 kcps @ 33 MBq and 45 kcps @ 40.60 MBq for the mouse, rat and monkey size scatter phantoms, respectively. The scatter fractions for these phantoms are 12.63%, 22.64% and 55.90%. We observe a peak sensitivity of up to 3.6% and a total sensitivity of up toSA,tot= 2.17%. For the NEMA image quality phantom we observe a uniformity of %STD= 4.22% with ordinary Poisson maximum likelihood expectation-maximization with 52 iterations. Here, recovery coefficients of 0.12, 0.64, 0.89, 0.93 and 0.91 for 1 mm, 2 mm, 3 mm, 4 mm and 5 mm rods are obtained and spill-over ratios of 0.08 and 0.14 for the water-filled and air-filled inserts, respectively.Significance.ThephenoPET and its laboratory are now in routine operation for the administration of [11C]CO2and non-invasive measurement of transport and allocation of11C-labelled photoassimilates in plants.
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Affiliation(s)
- Carsten Hinz
- IBG-2: Plant Sciences, Forschungszentrum Jülich GmbH, Wilhelm-Johnen-Str., D-52425 Jülich, Germany
| | - Siegfried Jahnke
- IBG-2: Plant Sciences, Forschungszentrum Jülich GmbH, Wilhelm-Johnen-Str., D-52425 Jülich, Germany
- Biodiversity, Faculty of Biology, University of Duisburg-Essen, Universitätsstr. 5, D-45141 Essen, Germany
| | - Ralf Metzner
- IBG-2: Plant Sciences, Forschungszentrum Jülich GmbH, Wilhelm-Johnen-Str., D-52425 Jülich, Germany
| | - Daniel Pflugfelder
- IBG-2: Plant Sciences, Forschungszentrum Jülich GmbH, Wilhelm-Johnen-Str., D-52425 Jülich, Germany
| | - Jürgen Scheins
- INM-4: Medical Imaging Physics, Forschungszentrum Jülich GmbH, Wilhelm-Johnen-Str., D-52425 Jülich, Germany
| | - Matthias Streun
- ZEA-2: Electronic Systems, Forschungszentrum Jülich GmbH, Wilhelm-Johnen-Str., D-52425 Jülich, Germany
| | - Robert Koller
- IBG-2: Plant Sciences, Forschungszentrum Jülich GmbH, Wilhelm-Johnen-Str., D-52425 Jülich, Germany
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Li G, Ma W, Li X, Yang W, Quan Z, Ma T, Wang J, Wang Y, Kang F, Wang J. Performance Evaluation of the uMI Panorama PET/CT System in Accordance with the National Electrical Manufacturers Association NU 2-2018 Standard. J Nucl Med 2024:jnumed.123.265929. [PMID: 38388513 DOI: 10.2967/jnumed.123.265929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Accepted: 01/11/2024] [Indexed: 02/24/2024] Open
Abstract
The uMI Panorama is a novel PET/CT system using silicon photomultiplier and application-specific integrated circuit technologies and providing exceptional spatial and time-of-flight (TOF) resolutions. The objective of this study was to assess the physical performance of the uMI Panorama in accordance with the National Electrical Manufacturers Association (NEMA) NU 2-2018 standard. Methods: Spatial resolution, sensitivity, count rate performance, accuracy, image quality, and TOF resolution were evaluated in accordance with the guidelines outlined in the NEMA NU 2-2018 standard. Energy resolution was determined using the same dataset acquired for the count rate performance evaluation. Images from a Hoffman brain phantom, a mini-Derenzo phantom, and 3 patient studies were evaluated to demonstrate system performance. Results: The transaxial spatial resolution at full width at half maximum was measured as 2.88 mm with a 1-cm offset from the center axial field of view. The sensitivity at the center axial field of view was 20.1 kcps/MBq. At an activity concentration of 73.0 kBq/mL, the peak noise-equivalent count rate (NECR) reached 576 kcps with a scatter fraction of approximately 33.2%. For activity concentrations at or below the peak NECR, the maximum relative count rate error among all slices remained consistently below 3%. When assessed using the NEMA image quality phantom, overall image contrast recovery ranged from 63.2% to 88.4%, whereas background variability ranged from 4.2% to 1.1%. TOF resolution was 189 ps at 5.3 kBq/mL and was consistently lower than 200 ps for activity concentrations at or below the peak NECR. The patient studies demonstrated that scans at 2 min/bed produced images characterized by low noise and high contrast. Clear delineation of nuclei, spinal cords, and other substructures of the brain was observed in the brain PET images. Conclusion: uMI Panorama, the world's first commercial PET system with sub-200-ps TOF resolution, demonstrated fine spatial and fast TOF resolutions, robust count rate performance, and high quantification accuracy across a wide range of activity levels. This advanced technology offers enhanced diagnostic capability for detecting small and low-contrast lesions while showing promising potential under high-count-rate imaging scenarios.
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Affiliation(s)
- Guiyu Li
- Department of Nuclear Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Wenhui Ma
- Department of Nuclear Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Xiang Li
- Department of Nuclear Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Weidong Yang
- Department of Nuclear Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Zhiyong Quan
- Department of Nuclear Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Taoqi Ma
- Department of Nuclear Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Junling Wang
- Department of Nuclear Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Yunya Wang
- Department of Nuclear Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Fei Kang
- Department of Nuclear Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Jing Wang
- Department of Nuclear Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an, China
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Merlet A, Presles B, Su KH, Salvadori J, Sayah F, Jozi H, Cochet A, Vrigneaud JM. Validation of a discovery MI 4-ring model according to the NEMA NU 2-2018 standards: from Monte Carlo simulations to clinical-like reconstructions. EJNMMI Phys 2024; 11:13. [PMID: 38294624 DOI: 10.1186/s40658-024-00616-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Accepted: 01/15/2024] [Indexed: 02/01/2024] Open
Abstract
BACKGROUND We propose a comprehensive evaluation of a Discovery MI 4-ring (DMI) model, using a Monte Carlo simulator (GATE) and a clinical reconstruction software package (PET toolbox). The following performance characteristics were compared with actual measurements according to NEMA NU 2-2018 guidelines: system sensitivity, count losses and scatter fraction (SF), coincidence time resolution (CTR), spatial resolution (SR), and image quality (IQ). For SR and IQ tests, reconstruction of time-of-flight (TOF) simulated data was performed using the manufacturer's reconstruction software. RESULTS Simulated prompt, random, true, scatter and noise equivalent count rates closely matched the experimental rates with maximum relative differences of 1.6%, 5.3%, 7.8%, 6.6%, and 16.5%, respectively, in a clinical range of less than 10 kBq/mL. A 3.6% maximum relative difference was found between experimental and simulated sensitivities. The simulated spatial resolution was better than the experimental one. Simulated image quality metrics were relatively close to the experimental results. CONCLUSIONS The current model is able to reproduce the behaviour of the DMI count rates in the clinical range and generate clinical-like images with a reasonable match in terms of contrast and noise.
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Affiliation(s)
- Antoine Merlet
- Imagerie et Vision artificielle, ImViA EA 7535, University of Burgundy, Dijon, France
| | - Benoît Presles
- Institut de Chimie Moléculaire de l'Université de Bourgogne (ICMUB), UMR CNRS 6302, University of Burgundy, Dijon, France
| | | | - Julien Salvadori
- ICANS, Institut de cancérologie Strasbourg Europe, Strasbourg, France
| | - Farzam Sayah
- Department of Nuclear Medicine, Georges-François Leclerc Cancer Centre, Dijon, France
| | - Hanieh Jozi
- Department of Nuclear Medicine, Georges-François Leclerc Cancer Centre, Dijon, France
| | - Alexandre Cochet
- Institut de Chimie Moléculaire de l'Université de Bourgogne (ICMUB), UMR CNRS 6302, University of Burgundy, Dijon, France
- Department of Nuclear Medicine, Georges-François Leclerc Cancer Centre, Dijon, France
| | - Jean-Marc Vrigneaud
- Institut de Chimie Moléculaire de l'Université de Bourgogne (ICMUB), UMR CNRS 6302, University of Burgundy, Dijon, France.
- Department of Nuclear Medicine, Georges-François Leclerc Cancer Centre, Dijon, France.
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Yamagishi S, Miwa K, Kamitaki S, Anraku K, Sato S, Yamao T, Kubo H, Miyaji N, Oguchi K. Performance Characteristics of a New-Generation Digital Bismuth Germanium Oxide PET/CT System, Omni Legend 32, According to NEMA NU 2-2018 Standards. J Nucl Med 2023; 64:1990-1997. [PMID: 37857503 DOI: 10.2967/jnumed.123.266140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 09/27/2023] [Indexed: 10/21/2023] Open
Abstract
The Omni Legend 32 PET/CT system features silicon photomultiplier (SiPM)-based detectors with bismuth germanium oxide crystals and a 32-cm axial field of view (FOV). The present study aimed to determine the performance characteristics of the Omni Legend 32 PET/CT system according to National Electrical Manufacturers Association (NEMA) NU 2-2018 standards. Methods: The PET component of this system comprises 22 detector modules; each module contains 24 detector blocks with 72 bismuth germanium oxide crystals with a volume of 4.1 × 4.1 × 30 mm coupled to 18 SiPM devices with a 6 × 6 mm area, resulting in an axial FOV of 32 cm. The spatial resolution, sensitivity, count rate performance, and image quality delivered by PET were evaluated using the NEMA NU 2-2018 standard. PET images of 2 patients were evaluated to get a visual first impression of the Omni Legend 32 PET/CT system together with Precision DL. Results: The average spatial resolution at 1, 10, and 20 cm from the central axis was 4.3, 5.3, and 6.2 mm, respectively, for filtered backprojection and 3.7, 4.3, and 5.1 mm, respectively, for ordered-subset expectation maximization. The NEMA sensitivity was 47.30 and 47.05 cps/kBq at the axial center of the FOV and at a 10-cm radial offset, respectively. The scatter fraction, count rate accuracy, and peak noise-equivalent count rates were 35.4%, 1.7%, and 501.7 kcps, respectively, at 15.7 kBq/mL. Contrast recovery for the NEMA body phantom from the smallest to the largest sphere ranged from 61.3% to 93.0%, with a background variability of 5.4%-11.7% and a lung error of 5.1% for Q.Clear (β-value, 50). Good patient image quality was obtained with the Omni Legend 32. Conclusion: The Omni Legend 32 has class-leading sensitivity and count rates within the category of whole-body PET systems while maintaining spatial resolution broadly comparable to that of other current SiPM-based PET/CT systems. This combination of properties results in a very good image quality.
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Affiliation(s)
- Shin Yamagishi
- Center of Radiology and Diagnostic Imaging, Aizawa Hospital, Nagano, Japan; and
| | - Kenta Miwa
- Department of Radiological Sciences, School of Health Sciences, Fukushima Medical University, Fukushima, Japan
| | - Shun Kamitaki
- Center of Radiology and Diagnostic Imaging, Aizawa Hospital, Nagano, Japan; and
| | - Kouichi Anraku
- Center of Radiology and Diagnostic Imaging, Aizawa Hospital, Nagano, Japan; and
| | - Shun Sato
- Center of Radiology and Diagnostic Imaging, Aizawa Hospital, Nagano, Japan; and
| | - Tensho Yamao
- Department of Radiological Sciences, School of Health Sciences, Fukushima Medical University, Fukushima, Japan
| | - Hitoshi Kubo
- Department of Radiological Sciences, School of Health Sciences, Fukushima Medical University, Fukushima, Japan
| | - Noriaki Miyaji
- Department of Radiological Sciences, School of Health Sciences, Fukushima Medical University, Fukushima, Japan
| | - Kazuhiro Oguchi
- Center of Radiology and Diagnostic Imaging, Aizawa Hospital, Nagano, Japan; and
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Rezaei H, Sheikhzadeh P, Ghafarian P, Zaidi H, Ay MR. Accurate modeling and performance evaluation of a total-body pet scanner using Monte Carlo simulations. Med Phys 2023; 50:6815-6827. [PMID: 37665768 DOI: 10.1002/mp.16707] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 08/22/2023] [Accepted: 08/22/2023] [Indexed: 09/06/2023] Open
Abstract
BACKGROUND The limited axial field-of-view (FOV) of conventional clinical positron emission tomography (PET) scanners (∼15 to 26 cm) allows detecting only 1% of all coincidence photons, hence limiting significantly their sensitivity. To overcome this limitation, the EXPLORER consortium developed the world's first total-body PET/CT scanner that significantly increased the sensitivity, thus enabling to decrease the scan duration or injected dose. PURPOSE The purpose of this study is to perform and validate Monte Carlo simulations of the uEXPLORER PET scanner, which can be used to devise novel conceptual designs and geometrical configurations through obtaining features that are difficult to obtain experimentally. METHODS The total-body uEXPLORER PET scanner was modeled using GATE Monte Carlo (MC) platform. The model was validated through comparison with experimental measurements of various performance parameters, including spatial resolution, sensitivity, count rate performance, and image quality, according to NEMA-NU2 2018 standards. Furthermore, the effects of the time coincidence window and maximum ring difference on the count rate and noise equivalent count rate (NECR) were evaluated. RESULTS Overall, the validation study showed that there was a good agreement between the simulation and experimental results. The differences between the simulated and experimental total sensitivity for the NEMA and extended phantoms at the center of the FOV were 2.3% and 0.0%, respectively. The difference in peak NECR was 9.9% for the NEMA phantom and 1.0% for the extended phantom. The average bias between the simulated and experimental results of the full-width-at-half maximum (FWHM) for six different positions and three directions was 0.12 mm. The simulations showed that using a variable coincidence time window based on the maximum ring difference can reduce the effect of random coincidences and improve the NECR compared to a constant time coincidence window. The NECR corresponding to 252-ring difference was 2.11 Mcps, which is larger than the NECR corresponding to 336-ring difference (2.04 Mcps). CONCLUSION The developed MC model of the uEXPLORER PET scanner was validated against experimental measurements and can be used for further assessment and design optimization of the scanner.
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Affiliation(s)
- Hadi Rezaei
- Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Science, Tehran, Iran
- Research Center for Molecular and Cellular Imaging (RCMCI), Advanced Medical Technologies and Equipment Institute (AMTEI), Tehran University of Medical Sciences (TUMS), Tehran, Iran
| | - Peyman Sheikhzadeh
- Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Science, Tehran, Iran
- Department of Nuclear Medicine, Imam Khomeini Hospital Complex, 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 Sciences, Tehran, Iran
| | - Habib Zaidi
- Division of Nuclear Medicine and Molecular Imaging, Geneva University Hospital, Geneva, 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 Science, Tehran, Iran
- Research Center for Molecular and Cellular Imaging (RCMCI), Advanced Medical Technologies and Equipment Institute (AMTEI), Tehran University of Medical Sciences (TUMS), Tehran, Iran
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Singh MK, Mohan P, Mahajan H, Kaushik C. Technical and clinical assessment of latest technology SiPM integrated digital PETCT scanner. Radiography (Lond) 2023; 29:705-711. [PMID: 37187068 DOI: 10.1016/j.radi.2023.04.020] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 04/05/2023] [Accepted: 04/26/2023] [Indexed: 05/17/2023]
Abstract
OBJECTIVE The aim of this study was to conduct a technical and clinical evaluation of a Silicon Photomultiplier (SiPM) integrated digital Positron Emission Tomography - Computed Tomography (PETCT) Scanner using National Electrical Manufacturers Association (NEMA) NU 2- 2018 standards. METHODS System sensitivity was measured by using a NEMA sensitivity phantom. Scatter fraction, count-rate performance, accuracy of count loss, and timing resolution were all computed. Clinical images were acquired and image quality was assessed and compared with published studies. RESULTS At 1 cm, tangential, radial, and axial spatial resolutions were 3.02 mm, 3.02 mm, and 2.73 mm at full width half maximum (FWHM), respectively. Sensitivity at centre and 10 cm was 10.359 cps/kBq and 9.741 cps/kBq, respectively. The timing resolution was measured at 372 ps. CONCLUSION The digital PETCT exhibits a high-spatial resolution and a superior timing resolution, which advances the diagnostic ability to detect small lesions and boosts the diagnostic confidence. IMPLICATIONS FOR PRACTICE Increases clinical relevance by improving the ability to detect and differentiate tiny or low-contrast lesions without compromising radiopharmaceutical dose or overall scan time.
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Affiliation(s)
- M K Singh
- Medikabazaar, Technopolis Knowledge Park, Mumbai, 400093, India
| | - P Mohan
- Mahajan Imaging, Hauz Khas Enclave, New Delhi, 110016, India
| | - H Mahajan
- Mahajan Imaging, Hauz Khas Enclave, New Delhi, 110016, India
| | - C Kaushik
- School of Health and Society, University of Salford, Manchester, M5 4WT, United Kingdom.
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Pommranz CM, Schmidt FP, Mannheim JG, Diebold SJ, Tenzer C, Santangelo A, Pichler BJ. Design and performance simulation studies of a breast PET insert integrable into a clinical whole-body PET/MRI scanner. Phys Med Biol 2023; 68. [PMID: 36753773 DOI: 10.1088/1361-6560/acba77] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Accepted: 02/08/2023] [Indexed: 02/10/2023]
Abstract
Objective. Three different breast positron emission tomography (PET) insert geometries are proposed for integration into an existing magnetic resonance imaging (MRI) breast coil (Breast Biopsy Coil, NORAS MRI products) to be used inside a whole-body PET/MRI scanner (Biograph mMR, Siemens Healthineers) to enhance the sensitivity and spatial resolution of imaging inside the breast.Approach. Monte Carlo simulations were performed to predict and compare the performance characteristics of the three geometries in terms of the sensitivity, spatial resolution, scatter fraction, and noise equivalent count rate (NECR). In addition, the background single count rate due to organ uptake in a clinical scan scenario was predicted using a realistic anthropomorphic phantom.Main results. In the center of the field of view (cFOV), absolute sensitivities of 3.1%, 2.7%, and 2.2% were found for Geometry A (detectors arranged in two cylinders), Geometry B (detectors arranged in two partial cylinders), and Geometry C (detectors arranged in two half cylinders combined with two plates), respectively. The full width at half maximum spatial resolution was determined to be 1.7 mm (Geometry A), 1.8 mm (Geometry B) and 2.0 mm (Geometry C) at 5 mm from the cFOV. Designs with multiple scintillation-crystal layers capable of determining the depth of interaction (DOI) strongly improved the spatial resolution at larger distances from the transaxial cFOV. The system scatter fractions were 33.1% (Geometries A and B) and 32.3% (Geometry C). The peak NECRs occurred at source activities of 300 MBq (Geometry A), 310 MBq (Geometry B) and 340 MBq (Geometry C). The background single-event count rates were 17.1 × 106cps (Geometry A), 15.3 × 106cps (Geometry B) and 14.8 × 106cps (Geometry C). Geometry A in the three-layer DOI variant exhibited the best PET performance characteristics but could be challenging to manufacture. Geometry C had the lowest impact on the spatial resolution and the lowest sensitivity among the investigated geometries.Significance. Geometry B in the two-layer DOI variant represented an effective compromise between the PET performance and manufacturing difficulty and was found to be a promising candidate for the future breast PET insert.
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Affiliation(s)
- C M Pommranz
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University Tuebingen, Roentgenweg 13, D-72076 Tuebingen, Germany.,Institute for Astronomy and Astrophysics, Eberhard Karls University Tuebingen, Sand 1, D-72076 Tuebingen, Germany
| | - F P Schmidt
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University Tuebingen, Roentgenweg 13, D-72076 Tuebingen, Germany.,Department of Nuclear Medicine and Clinical Molecular Imaging, University Hospital Tuebingen, Otfried-Mueller-Strasse 14, D-72076 Tuebingen, Germany
| | - J G Mannheim
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University Tuebingen, Roentgenweg 13, D-72076 Tuebingen, Germany.,Cluster of Excellence iFIT (EXC 2180) Image Guided and Functionally Instructed Tumor Therapies, University of Tuebingen, Tuebingen, Germany
| | - S J Diebold
- Institute for Astronomy and Astrophysics, Eberhard Karls University Tuebingen, Sand 1, D-72076 Tuebingen, Germany
| | - C Tenzer
- Institute for Astronomy and Astrophysics, Eberhard Karls University Tuebingen, Sand 1, D-72076 Tuebingen, Germany
| | - A Santangelo
- Institute for Astronomy and Astrophysics, Eberhard Karls University Tuebingen, Sand 1, D-72076 Tuebingen, Germany
| | - B J Pichler
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University Tuebingen, Roentgenweg 13, D-72076 Tuebingen, Germany.,Cluster of Excellence iFIT (EXC 2180) Image Guided and Functionally Instructed Tumor Therapies, University of Tuebingen, Tuebingen, Germany
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10
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Zeimpekis KG, Mercolli L, Conti M, Sari H, Prenosil G, Shi K, Rominger A. Phantom-based evaluation of yttrium-90 datasets using biograph vision quadra. Eur J Nucl Med Mol Imaging 2023; 50:1168-82. [PMID: 36504278 DOI: 10.1007/s00259-022-06074-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2022] [Accepted: 12/04/2022] [Indexed: 12/14/2022]
Abstract
PURPOSE The image quality characteristics of two NEMA phantoms with yttrium-90 (90Y) were evaluated on a long axial field-of-view (AFOV) PET/CT. The purpose was to identify the optimized reconstruction setup for the imaging of patients with hepatocellular carcinoma after 90Y radioembolization. METHODS Two NEMA phantoms were used, where one had a 1:10 sphere to background activity concentration ratio and the second had cold background. Reconstruction parameters used are as follows: iterations 2 to 8, Gaussian filter 2- to 6-mm full-width-at-half-maximum, reconstruction matrices 440 × 440 and 220 × 220, high sensitivity (HS), and ultra-high sensitivity (UHS) modes. 50-, 40-, 30-, 20-, 10-, and 5-min acquisitions were reconstructed. The measurements included recovery coefficients (RC), signal-to-noise ratio (SNR), background variability, and lung error which measures the residual error in the corrections. Patient data were reconstructed with 20-, 10-, 5-, and 1-min time frames and evaluated in terms of SNR. RESULTS The RC for the hot phantom was 0.36, 0.45, 0.53, 0.63, 0.68, and 0.84 for the spheres with diameters of 10, 13, 17, 22, 28, and 37 mm, respectively, for UHS 2 iterations, a 220 × 220 matrix, and 50-min acquisition. The RC values did not differ with acquisition times down to 20 min. The SNR was the highest for 2 iterations, measured 11.7, 16.6, 17.6, 19.4, 21.9, and 27.7 while the background variability was the lowest (27.59, 27.08, 27.36, 26.44, 30.11, and 33.51%). The lung error was 18%. For the patient dataset, the SNR was 19%, 20%, 24%, and 31% higher for 2 iterations compared to 4 iterations for 20-, 10-, 5-, and 1-min time frames, respectively. CONCLUSIONS This study evaluates the NEMA image quality of a long AFOV PET/CT scanner with 90Y. It provides high RC for the smallest sphere compared to other standard AFOV scanners at shorter scan times. The maximum patient SNR was for 2 iterations, 20 min, while 5 min delivers images with acceptable SNR.
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11
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Morimoto-Ishikawa D, Hanaoka K, Watanabe S, Yamada T, Yamakawa Y, Minagawa S, Takenouchi S, Ohtani A, Mizuta T, Kaida H, Ishii K. Evaluation of the performance of a high-resolution time-of-flight PET system dedicated to the head and breast according to NEMA NU 2-2012 standard. EJNMMI Phys 2022; 9:88. [PMID: 36525103 PMCID: PMC9758266 DOI: 10.1186/s40658-022-00518-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Accepted: 12/06/2022] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND This study evaluated the physical performance of a positron emission tomography (PET) system dedicated to the head and breast according to the National Electrical Manufacturers Association (NEMA) NU2-2012 standard. METHODS The spatial resolution, sensitivity, scatter fraction, count rate characteristics, corrections for count losses and randoms, and image quality of the system were determined. All measurements were performed according to the NEMA NU2-2012 acquisition protocols, but image quality was assessed using a brain-sized phantom. Furthermore, scans of the three-dimensional (3D) Hoffmann brain phantom and mini-Derenzo phantom were acquired to allow visual evaluation of the imaging performance for small structures. RESULTS The tangential, radial, and axial full width at half maximum (FWHM) at a 10-mm offset in half the axial field of view were measured as 2.3, 2.5, and 2.9 mm, respectively. The average system sensitivity at the center of the field of view and at a 10-cm radial offset was 7.18 and 8.65 cps/kBq, respectively. The peak noise-equivalent counting rate was 35.2 kcps at 4.8 kBq/ml. The corresponding scatter fraction at the peak noise-equivalent counting rate was 46.8%. The peak true rate and scatter fraction at 8.6 kBq/ml were 127.8 kcps and 54.3%, respectively. The percent contrast value for a 10-mm sphere was approximately 50%. On the 3D Hoffman brain phantom image, the structures of the thin layers composing the phantom were visualized on the sagittal and coronal images. On the mini-Derenzo phantom, each of the 1.6-mm rods was clearly visualized. CONCLUSION Taken together, these results indicate that the head- and breast-dedicated PET system has high resolution and is well suited for clinical PET imaging.
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Affiliation(s)
- Daisuke Morimoto-Ishikawa
- grid.413111.70000 0004 0466 7515Division of Positron Emission Tomography, Institute of Advanced Clinical Medicine, Kindai University Hospital, 377-2 Ohno-Higashi, Osakasayama, Osaka 589-8511 Japan
| | - Kohei Hanaoka
- grid.413111.70000 0004 0466 7515Division of Positron Emission Tomography, Institute of Advanced Clinical Medicine, Kindai University Hospital, 377-2 Ohno-Higashi, Osakasayama, Osaka 589-8511 Japan
| | - Shota Watanabe
- grid.413111.70000 0004 0466 7515Division of Positron Emission Tomography, Institute of Advanced Clinical Medicine, Kindai University Hospital, 377-2 Ohno-Higashi, Osakasayama, Osaka 589-8511 Japan
| | - Takahiro Yamada
- grid.413111.70000 0004 0466 7515Division of Positron Emission Tomography, Institute of Advanced Clinical Medicine, Kindai University Hospital, 377-2 Ohno-Higashi, Osakasayama, Osaka 589-8511 Japan
| | - Yoshiyuki Yamakawa
- grid.274249.e0000 0004 0571 0853Medical Systems Division, Shimadzu Corporation, Kyoto, Japan
| | - Suzuka Minagawa
- grid.274249.e0000 0004 0571 0853Medical Systems Division, Shimadzu Corporation, Kyoto, Japan
| | - Shiho Takenouchi
- grid.274249.e0000 0004 0571 0853Medical Systems Division, Shimadzu Corporation, Kyoto, Japan
| | - Atsushi Ohtani
- grid.274249.e0000 0004 0571 0853Medical Systems Division, Shimadzu Corporation, Kyoto, Japan
| | - Tetsuro Mizuta
- grid.274249.e0000 0004 0571 0853Medical Systems Division, Shimadzu Corporation, Kyoto, Japan
| | - Hayato Kaida
- grid.413111.70000 0004 0466 7515Division of Positron Emission Tomography, Institute of Advanced Clinical Medicine, Kindai University Hospital, 377-2 Ohno-Higashi, Osakasayama, Osaka 589-8511 Japan ,grid.258622.90000 0004 1936 9967Department of Radiology, Kindai University Faculty of Medicine, Osakasayama, Japan
| | - Kazunari Ishii
- grid.413111.70000 0004 0466 7515Division of Positron Emission Tomography, Institute of Advanced Clinical Medicine, Kindai University Hospital, 377-2 Ohno-Higashi, Osakasayama, Osaka 589-8511 Japan ,grid.258622.90000 0004 1936 9967Department of Radiology, Kindai University Faculty of Medicine, Osakasayama, Japan
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12
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Emvalomenos G, Trajanovska S, Pham BTT, Doughty P, Burnet J, Smith I, Garipov R, Gregoire MC, Sunn N, McGrath J, Meikle SR. Performance evaluation of a PET insert for preclinical MRI in stand-alone PET and simultaneous PET-MRI modes. EJNMMI Phys 2021; 8:68. [PMID: 34626239 PMCID: PMC8502182 DOI: 10.1186/s40658-021-00415-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Accepted: 09/20/2021] [Indexed: 11/10/2022] Open
Abstract
Background This study aimed to evaluate the performance of a preclinical PET insert in three configurations: as a stand-alone unit outside the MRI bore, inside the bore of a cryogen-free 3T MRI and, finally, while performing simultaneous PET/MRI studies. Methods The PET insert consists of two rings of six detectors, each detector comprising 8 × 12 SiPMs reading out dual offset layers of pixelated LYSO crystals with a 1.4-mm pitch. The inner diameter is 60 mm, transaxial field of view (FoV) 40 mm and axial FoV 98 mm. Evaluation was based on NEMA NU 4-2008 guidelines with appropriate modifications. Spatial resolution and sensitivity were measured inside and outside the MR bore. Image quality, count rate and quantitative performance were measured in all three configurations. The effect of temperature stability on PET sensitivity during fast spin echo sequences was also evaluated. B0 field homogeneity and T1 and T2 relaxation times were measured using a water-filled phantom, with and without simultaneous PET operation. Finally, PET and MRI scans of a mouse injected with 10 MBq [18F]NaF and a mouse injected with 16 MBq [18F]FDG were performed in sequential and simultaneous modes. Results Peak absolute sensitivity was 10.15% with an energy window of 250–750 keV. Absolute sensitivity values outside and inside the MR bore with MR idle agreed to within 0.1%. Outside the MR bore, spatial resolution was 1.21/1.59 mm FWHM (radial/tangential) 5 mm from the centre of the FoV which compared well with 1.19/1.26 mm FWHM inside the MR bore. There were no substantial differences between all three scan configurations in terms of peak NEC rate (175 kcps at 17 MBq), scatter or random fractions. Uniformity and recovery coefficients were also consistent between scanning modes. B0 field homogeneity and T1 and T2 relaxation times were unaltered by the presence of the PET insert. No significant differences were observed between sequential and simultaneous scans of the animals. Conclusions We conclude that the performance of the PET insert and MRI system is not significantly affected by the scanning mode.
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Affiliation(s)
- Gaelle Emvalomenos
- Sydney School of Health Sciences, The University of Sydney, Camperdown, NSW, 2050, Australia. .,Brain and Mind Centre, The University of Sydney, 100 Mallett Street, Camperdown, NSW, 2050, Australia.
| | - Sofie Trajanovska
- Sydney Imaging Core Research Facility, The University of Sydney, Camperdown, NSW, 2050, Australia
| | - Binh T T Pham
- Sydney Imaging Core Research Facility, The University of Sydney, Camperdown, NSW, 2050, Australia
| | | | | | - Isabelle Smith
- School of Physics, The University of Sydney, Camperdown, NSW, 2050, Australia
| | | | - Marie-Claude Gregoire
- Brain and Mind Centre, The University of Sydney, 100 Mallett Street, Camperdown, NSW, 2050, Australia.,Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW, 2234, Australia
| | - Nana Sunn
- Sydney Imaging Core Research Facility, The University of Sydney, Camperdown, NSW, 2050, Australia
| | | | - Steven R Meikle
- Sydney School of Health Sciences, The University of Sydney, Camperdown, NSW, 2050, Australia.,Brain and Mind Centre, The University of Sydney, 100 Mallett Street, Camperdown, NSW, 2050, Australia
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Prenosil GA, Sari H, Fürstner M, Afshar-Oromieh A, Shi K, Rominger A, Hentschel M. Performance Characteristics of the Biograph Vision Quadra PET/CT system with long axial field of view using the NEMA NU 2-2018 Standard. J Nucl Med 2021; 63:476-484. [PMID: 34301780 DOI: 10.2967/jnumed.121.261972] [Citation(s) in RCA: 85] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 05/25/2021] [Indexed: 11/16/2022] Open
Abstract
Purpose: To evaluate the performance of the Biograph Vision Quadra (Siemens Healthineers) PET/CT system. This new system is based on the Siemens Biograph Vision 600, using the same silicon photomultiplier-based detectors with 3.2×3.2×20-mm lutetium-oxoorthosilicate crystals. The Quadra's 32 detector rings provide a fourfold larger axial field of view (AFOV) of 106 cm, enabling imaging of major organs in one bed position. Methods: Physical performance of the scanner was evaluated according to the National Electrical Manufacturers Association NU 2-2018 standard with additional experiments to characterize energy resolution. Image quality was assessed with foreground to background ratios of 4:1 and 8:1. Additionally, a clinical 18F-FDG-PET study was reconstructed with varying frame durations. In all experiments, data were acquired using the Quadra's maximum ring distance of 322 crystals (MRD 322), while image reconstructions could only be performed with a maximum ring distance of 85 crystals rings (MRD 85). Results: The spatial resolution at full width half maximum in radial, tangential and axial directions were 3.3, 3.4 and 3.8 mm respectively. The sensitivity was 83 cps/kBq for MRD 85 and 176 cps/kBq for MRD 322. The NECRs at peak were 1613 kcps for MRD 85 and 2956 kcps for MRD 322, both at 27.5 kBq/mL. The respective scatter fractions at peak NECR equaled 36 % and 37 %. The TOF resolution at peak NECR was 228 ps for MRD 85 and 230 ps for MRD 322. Image contrast recovery ranged from 69.6% to 86.9 % for 4:1 contrast ratios and from 77.7 % to 92.6 % for 8:1 contrast ratios reconstructed using PSF-TOF with 8 iterations and 5 subsets. Thirty seconds frames provided readable lesion detectability and acceptable noise levels in clinical images. Conclusion: The Biograph Vision Quadra PET/CT has similar spatial and time resolution compared to the Biograph Vision 600 but exhibits improved sensitivity and NECR due to its extended AFOV. The reported spatial resolution, time resolution, and sensitivity makes it a competitive new device in the class of PET-scanners with extended AFOV.
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Affiliation(s)
- George Amadeus Prenosil
- Department of Nuclear Medicine, Inselspital, Bern University Hospital, University of Bern, Switzerland
| | - Hasan Sari
- Department of Nuclear Medicine, Inselspital, Bern University Hospital, University of Bern, Switzerland
| | - Markus Fürstner
- Department of Nuclear Medicine, Inselspital, Bern University Hospital, University of Bern, Switzerland
| | - Ali Afshar-Oromieh
- Department of Nuclear Medicine, Inselspital, Bern University Hospital, University of Bern, Switzerland
| | - Kuangyu Shi
- Department of Nuclear Medicine, Inselspital, Bern University Hospital, University of Bern, Switzerland
| | - Axel Rominger
- Department of Nuclear Medicine, Inselspital, Bern University Hospital, University of Bern, Switzerland
| | - Michael Hentschel
- Department of Nuclear Medicine, Inselspital, Bern University Hospital, University of Bern, Switzerland
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Raji S, Adekayaoja FA, Agaku EA, Akujobi J, Hamzat AA. North-eastern Nigeria: assessing the response capacity of National Emergency Management Agency to the plights of internally displaced persons. Heliyon 2021; 7:e07274. [PMID: 34189316 PMCID: PMC8215212 DOI: 10.1016/j.heliyon.2021.e07274] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 04/07/2021] [Accepted: 06/07/2021] [Indexed: 12/03/2022] Open
Abstract
The plights of Internally Displaced Persons (IDPs), including hunger, rape, insecurity, and death, have assumed a frightening dimension in North-eastern Nigeria with the sustained intervention of the National Emergency Management Agency (NEMA) to ameliorate their sufferings. This paper aimed to assess the response capacity of NEMA to the plights of the IDPs in North-eastern Nigeria. The objectives of the study were to examine the nature and dimensions of the plights of the IDPs in the Northeast, identify their coping strategies, and assess the impact of NEMA's response strategies on the burgeoning situation. The study used a qualitative survey research design, in which 166 key Informant Interviews (KII) were conducted. The primary designs were complemented by secondary data, which was derived from books, journal articles, and News tabloids. Data generated were descriptively analyzed. Major findings from the paper were that the Boko Haram insurgency was primarily responsible for the mass displacement of persons in North-eastern Nigeria. The IDPs are facing lots of challenges in the camps with weak coping strategies while the intervention of NEMA through the provision of relief materials, rehabilitation and resettlement programs, and linking of the displaced with family members have reduced the plights of the IDPs. However, the Agency currently has the minimal operational capacity to ameliorate the plights of the IDPs due to the protracted nature of the insurgency, legal restriction on the operational mandates of NEMA, corruption, and limited funding of the agency. The Study recommended improved funding of the Agency and enactment of IDP-specific constitutional roles for maximum impact of NEMA on the amelioration of the plights of the IDPs in North-Eastern Nigeria.
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15
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Ghabrial A, Franklin DR, Zaidi H. A Monte Carlo simulation study of scatter fraction and the impact of patient BMI on scatter in long axial field-of-view PET scanners. Z Med Phys 2021; 31:305-315. [PMID: 33593642 DOI: 10.1016/j.zemedi.2021.01.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 01/24/2021] [Accepted: 01/25/2021] [Indexed: 11/16/2022]
Abstract
The NEMA NU-2 standard describes a protocol for measurement of scatter fraction (SF) using an axially-aligned line source, offset at 45mm from the central axis, in a cylindrical polyethylene phantom. In this work, which is an extension of our preliminary results previuosly published in the Proceedings of IEEE NSS/MIC 2018 [1], we aim to evaluate the performance of the NEMA NU-2 SF protocol in a Siemens Biograph mCT PET/CT whole-body scanner and a long axial field-of-view (LAFOV) total-body PET scanner to determine whether modifications to the NEMA NU-2 SF protocol are needed for the characterisation of scatter in such scanners. In addition, we evaluate the impact of patient body mass index (BMI) on SF in a LAFOV scanner. The Siemens Biograph mCT and a typical LAFOV PET scanner were modelled in GATE. Monte Carlo simulations were performed to validate the mCT scanner model against published experimental results. SF was estimated using a modified NEMA NU-2 protocol with variable radial offsets on both scanners and compared to ground truth SF measurements obtained with a uniform-activity cylindrical phantom. Correlation between BMI and SF in the LAFOV scanner was evaluated by simulating anthropomorphic phantoms with different BMIs and realistic 18F-FDG distributions, together with uniformly-filled 200cm long cylindrical phantoms with equivalent effective diameters. The optimal offset was found to be either 60mm or 80mm, depending on the chosen optimality metric. We conclude that modifications to NEMA NU-2 are required for accurate SF characterisation in whole-body and LAFOV scanners. Finally, SF in anthropomorphic phantoms with realistic tissue concentrations of 18F-FDG was found to be strongly correlated with SF in an equivalent-volume cylindrical phantom for the LAFOV PET scanner; BMI was also found to strongly positively correlate with the SF.
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Affiliation(s)
- Amir Ghabrial
- Division of Nuclear Medicine and Molecular Imaging, Geneva University Hospital, CH-1211 Geneva, Switzerland; University of Technology Sydney, Ultimo NSW 2007, Australia
| | | | - Habib Zaidi
- Division of Nuclear Medicine and Molecular Imaging, Geneva University Hospital, CH-1211 Geneva, Switzerland; Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, 9700 RB Groningen, The Netherlands; Department of Nuclear Medicine, University of Southern Denmark, DK-500 Odense, Denmark
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16
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Teuho J, Riehakainen L, Honkaniemi A, Moisio O, Han C, Tirri M, Liu S, Grönroos TJ, Liu J, Wan L, Liang X, Ling Y, Hua Y, Roivainen A, Knuuti J, Xie Q, Teräs M, D'Ascenzo N, Klén R. Evaluation of image quality with four positron emitters and three preclinical PET/CT systems. EJNMMI Res 2020; 10:155. [PMID: 33301074 PMCID: PMC7728905 DOI: 10.1186/s13550-020-00724-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Accepted: 10/21/2020] [Indexed: 01/19/2023] Open
Abstract
Background We investigated the image quality of 11C, 68Ga, 18F and 89Zr, which have different positron fractions, physical half-lifes and positron ranges. Three small animal positron emission tomography/computed tomography (PET/CT) systems were used in the evaluation, including the Siemens Inveon, RAYCAN X5 and Molecubes β-cube. The evaluation was performed on a single scanner level using the national electrical manufacturers association (NEMA) image quality phantom and analysis protocol. Acquisitions were performed with the standard NEMA protocol for 18F and using a radionuclide-specific acquisition time for 11C, 68Ga and 89Zr. Images were assessed using percent recovery coefficient (%RC), percentage standard deviation (%STD), image uniformity (%SD), spill-over ratio (SOR) and evaluation of image quantification.
Results 68Ga had the lowest %RC (< 62%) across all systems. 18F had the highest maximum %RC (> 85%) and lowest %STD for the 5 mm rod across all systems. For 11C and 89Zr, the maximum %RC was close (> 76%) to the %RC with 18F. A larger SOR were measured in water with 11C and 68Ga compared to 18F on all systems. SOR in air reflected image reconstruction and data correction performance. Large variation in image quantification was observed, with maximal errors of 22.73% (89Zr, Inveon), 17.54% (89Zr, RAYCAN) and − 14.87% (68Ga, Molecubes). Conclusions The systems performed most optimal in terms of NEMA image quality parameters when using 18F, where 11C and 89Zr performed slightly worse than 18F. The performance was least optimal when using 68Ga, due to large positron range. The large quantification differences prompt optimization not only by terms of image quality but also quantification. Further investigation should be performed to find an appropriate calibration and harmonization protocol and the evaluation should be conducted on a multi-scanner and multi-center level.
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Affiliation(s)
- Jarmo Teuho
- Turku PET Centre, University of Turku, Turku, Finland. .,Turku PET Centre, Turku University Hospital, Turku, Finland.
| | | | | | - Olli Moisio
- Turku PET Centre, University of Turku, Turku, Finland
| | - Chunlei Han
- Turku PET Centre, Turku University Hospital, Turku, Finland
| | - Marko Tirri
- Turku PET Centre, University of Turku, Turku, Finland.,Department of Biomedicine, University of Turku, Turku, Finland
| | - Shihao Liu
- RaySolution Digital Medical Imaging Co., Ltd, Ezhou, People's Republic of China
| | - Tove J Grönroos
- Turku PET Centre, University of Turku, Turku, Finland.,MediCity Research Laboratory, University of Turku, Turku, Finland
| | - Jie Liu
- School of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, People's Republic of China
| | - Lin Wan
- School of Software Engineering, Huazhong University of Science and Technology, Wuhan, People's Republic of China
| | - Xiao Liang
- School of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, People's Republic of China
| | - Yiqing Ling
- School of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, People's Republic of China
| | - Yuexuan Hua
- School of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, People's Republic of China
| | - Anne Roivainen
- Turku PET Centre, University of Turku, Turku, Finland.,Turku PET Centre, Turku University Hospital, Turku, Finland.,Turku Center for Disease Modeling, University of Turku, Turku, Finland
| | - Juhani Knuuti
- Turku PET Centre, University of Turku, Turku, Finland.,Turku PET Centre, Turku University Hospital, Turku, Finland
| | - Qingguo Xie
- School of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, People's Republic of China.,Department of Medical Physics and Engineering, Istituto Neurologico Mediterraneo NEUROMED I.R.C.C.S., Pozzilli, Italy.,Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, China
| | - Mika Teräs
- Department of Biomedicine, University of Turku, Turku, Finland.,Department of Medical Physics, Turku University Hospital, Turku, Finland
| | - Nicola D'Ascenzo
- School of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, People's Republic of China.,Department of Medical Physics and Engineering, Istituto Neurologico Mediterraneo NEUROMED I.R.C.C.S., Pozzilli, Italy
| | - Riku Klén
- Turku PET Centre, University of Turku, Turku, Finland
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Carlier T, Ferrer L, Conti M, Bodet-Milin C, Rousseau C, Bercier Y, Bendriem B, Kraeber-Bodéré F. From a PMT-based to a SiPM-based PET system: a study to define matched acquisition/reconstruction parameters and NEMA performance of the Biograph Vision 450. EJNMMI Phys 2020; 7:55. [PMID: 32880792 DOI: 10.1186/s40658-020-00323-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Accepted: 08/16/2020] [Indexed: 12/16/2022] Open
Abstract
Background The purpose of this work was to propose an approach based on noise measurement to adapt present clinical acquisition and reconstruction parameters adapted to a PMT-based system (Biograph mCT) to a SiPM-based system (Biograph Vision 450) sharing identical geometrical properties. The NEMA performance (NEMA) of the recently released Biograph Vision 450 PET/CT (Vision) was also derived. Methods All measurements were conducted on Vision and Biograph mCT with TrueV (mCT). A full NEMA-based performance was derived for Vision only. The adaptation of acquisition and reconstruction parameters from mCT to Vision was done using the NEMA image quality phantom. The noise level reached using mCT was set as the reference value for six different numbers of net true coincidences. The noise level computed using Vision was matched to the reference noise level (within 0.01%) using a different reconstruction set-up to determine the potential reduction of count numbers for the same noise level. Results Vision sensitivity was 9.1 kcps/MBq for a timing resolution of 213 ps at 5.3 kBq/mL. The NEMA-based CR for the 10-mm sphere was better than 75% regardless the reconstruction set-up studied. The mCT reference noise properties could be achieved using Vision with a scan time reduction (STR) of 1.34 with four iterations and a 440 × 440 matrix size (or STR = 1.89 with a 220 × 220 matrix size) together with a 3D CR improvement of 53% for the 10-mm sphere (24% using 220 × 220). Conclusion The Vision exhibited improved NEMA performances compared to mCT. Using the proposed approach, the time acquisition could be divided by almost two, while keeping the same noise properties as that of mCT with a marked improvement of contrast recovery.
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Salvadori J, Labour J, Odille F, Marie PY, Badel JN, Imbert L, Sarrut D. Monte Carlo simulation of digital photon counting PET. EJNMMI Phys 2020; 7:23. [PMID: 32335787 PMCID: PMC7183520 DOI: 10.1186/s40658-020-00288-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Accepted: 03/17/2020] [Indexed: 12/14/2022] Open
Abstract
A GATE Monte Carlo model of the Philips Vereos digital photon counting PET imaging system using silicon photo-multiplier detectors was proposed. It was evaluated against experimental data in accordance with NEMA guidelines. Comparisons were performed using listmode data in order to remain independent of image reconstruction algorithms. An original line of response-based method is proposed to estimate intrinsic spatial resolution without reconstruction. Four sets of experiments were performed: (1) count rates and scatter fraction, (2) energy and timing resolutions, (3) sensitivity, and (4) intrinsic spatial resolution. Experimental and simulated data were found to be in good agreement, with overall differences lower than 10% for activity concentrations used in most standard clinical applications. Illustrative image reconstructions were provided. In conclusion, the proposed Monte Carlo model was validated and can be used for numerous studies such as optimizing acquisition parameters or reconstruction algorithms.
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Affiliation(s)
- Julien Salvadori
- IADI, INSERM UMR 1254, Université de Lorraine, Nancy, France. .,Département de médecine nucléaire et plateforme Nancyclotep, CHRU-Nancy, Université de Lorraine, Nancy, France.
| | - Joey Labour
- CREATIS, Centre Léon Bérard, CNRS UMR 5220, INSERM U 1044, Université de Lyon; INSA-Lyon; Université Lyon 1, Lyon, France
| | - Freddy Odille
- IADI, INSERM UMR 1254, Université de Lorraine, Nancy, France
| | - Pierre-Yves Marie
- Département de médecine nucléaire et plateforme Nancyclotep, CHRU-Nancy, Université de Lorraine, Nancy, France.,DCAC, INSERM UMR 1116, Université de Lorraine, Nancy, France
| | - Jean-Noël Badel
- CREATIS, Centre Léon Bérard, CNRS UMR 5220, INSERM U 1044, Université de Lyon; INSA-Lyon; Université Lyon 1, Lyon, France
| | - Laëtitia Imbert
- IADI, INSERM UMR 1254, Université de Lorraine, Nancy, France.,Département de médecine nucléaire et plateforme Nancyclotep, CHRU-Nancy, Université de Lorraine, Nancy, France
| | - David Sarrut
- CREATIS, Centre Léon Bérard, CNRS UMR 5220, INSERM U 1044, Université de Lyon; INSA-Lyon; Université Lyon 1, Lyon, France
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Emami A, Ghadiri H, Ghafarian P, Geramifar P, Ay MR. Performance evaluation of developed dedicated breast PET scanner and improvement of the spatial resolution by wobbling: a Monte Carlo study. Jpn J Radiol 2020; 38:790-799. [PMID: 32253654 DOI: 10.1007/s11604-020-00966-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Accepted: 03/26/2020] [Indexed: 11/25/2022]
Abstract
PURPOSE Molecular imaging, particularly PET scanning, has become an important cancer diagnostic tool. Whole-body PET is not effective for local staging of cancer because of their declining efficiency in detecting small lesions. The preliminary results of the performance evaluation of designed dedicated breast PET scanner presented. METHODS AND MATERIALS A new scanner is based on LYSO crystals coupled with SiPM, and it consists of 14 compact modules with a transaxial FOV of 180 mm in diameter. In this study, initial GATE simulation studies were performed to predict the spatial resolution, absolute sensitivity, noise equivalent count rate (NECR) and scatter fraction (SF) of the new design. Spatial wobbling acquisitions were also implemented. Finally, the obtained projections were reconstructed using analytical and iterative algorithms. RESULTS The simulation results indicate that absolute sensitivity is 1.42% which is appropriate than other commercial breast PET systems. The calculated SF and NECR in our design are 20.6% and 21.8 kcps. The initial simulation results demonstrate the potential of this design for breast cancer detection. A small wobble motion to improve spatial resolution and contrast. CONCLUSION The performance of the dedicated breast PET scanner is considered to be reasonable enough to support its use in breast cancer imaging.
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Affiliation(s)
- Azadeh Emami
- Research Center for Molecular and Cellular Imaging, Tehran University of Medical Sciences, Tehran, Iran.,Department of Medical Physics and Biomedical Engineering, Faculty of Medicine, Tehran University of Medical Sciences, Sina Campus, Tehran, 1417613151, Iran.,International Campus, Tehran University of Medical Sciences, Tehran, Iran
| | - Hossein Ghadiri
- Research Center for Molecular and Cellular Imaging, Tehran University of Medical Sciences, Tehran, Iran. .,Department of Medical Physics and Biomedical Engineering, Faculty of Medicine, Tehran University of Medical Sciences, Sina Campus, Tehran, 1417613151, 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 Sciences, Tehran, Iran.
| | - Parham Geramifar
- Research Center for Nuclear Medicine, Shariati Hospital, Tehran University of Medical Sciences, Tehran, Iran.
| | - Mohammad Reza Ay
- Research Center for Molecular and Cellular Imaging, Tehran University of Medical Sciences, Tehran, Iran. .,Department of Medical Physics and Biomedical Engineering, Faculty of Medicine, Tehran University of Medical Sciences, Sina Campus, Tehran, 1417613151, Iran.
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Chicheportiche A, Marciano R, Orevi M. Comparison of NEMA characterizations for Discovery MI and Discovery MI-DR TOF PET/CT systems at different sites and with other commercial PET/CT systems. EJNMMI Phys 2020; 7:4. [PMID: 31938953 PMCID: PMC6960280 DOI: 10.1186/s40658-020-0271-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Accepted: 01/05/2020] [Indexed: 12/19/2022] Open
Abstract
Background This article compares the physical performance of the 4-ring digital Discovery MI (DMI) and PMT-based Discovery MI-DR (DMI-DR) PET/CT systems. Physical performance was assessed according to the NEMA NU 2-2012 standards. Performance measures included spatial resolution, image quality, scatter fraction and count rate performance, and sensitivity. Energy and timing resolutions were also measured. Published DMI and DMI-DR performance studies from other centers are reviewed and compared. Results 4-ring DMI spatial resolution at 1-cm radial offset in the radial, tangential and axial directions was 4.62, 4.18 and 4.57 mm, respectively, compared with the DMI-DR system values of 4.58, 4.52, and 5.31 mm. Measured sensitivity was 13.3 kcps/MBq at the center of the FOV and 13.4 kcps/MBq 10 cm off-center for the SiPM-based DMI system. DMI-DR system sensitivity was 6.3 kcps/MBq at the center of the FOV and 6.8 kcps/MBq at 10 cm off-center. DMI measured noise equivalent count rate peak was 175.6 kcps at 20.1 kBq/ml; DMI-DR was 146.7 kcps at 31.7 kBq/ml. Scatter fraction was 40.5% and 36.6%, respectively. DMI image contrast recovery (CR) values ranged from 73.2% (10 mm sphere) to 91.0% (37 mm sphere); DMI-DR, values ranged from 68.4% to 91.4%. DMI background variability (BV) was 1.8%–6.5%; DMI-DR was 2.3%–9.1%. The Q.Clear algorithm improved image quality, increasing CR and decreasing BV in both systems. The photopeak energy resolution was 9.63% and 12.19% for DMI and DMI-DR, respectively. The time-of-flight (TOF) resolution was 377.26 ps and 552.71 ps, respectively. Compared with measurements in other centers, results were similar and showed an absolute mean relative deviation of 6% for DMI and 7% for DMI-DR overall performance results. Conclusions Performance measures were higher for the 4-ring DMI than the DMI-DR system. The biggest advantages of the 4-ring DMI vs DMI-DR are improved sensitivity and count rate performance. This should allow a better image signal-to-noise ratio (SNR) for the same acquisition times or, similar SNR with lower acquisition times or injected activity. In its 3-ring configuration, the DMI showed worse performance results than the PMT-based system in terms of count rate scatter fraction and image quality (for similar axial FOV).
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Affiliation(s)
- Alexandre Chicheportiche
- Department of Nuclear Medicine and Biophysics, Hadassah Hebrew University Medical Center, 91120, Jerusalem, Israel.
| | | | - Marina Orevi
- Department of Nuclear Medicine and Biophysics, Hadassah Hebrew University Medical Center, 91120, Jerusalem, Israel
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21
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Mac PA, Kroeger A, Airiohuodion PE. Needs assessment of emergency medical and rescue services in Abuja/Nigeria and environs. BMC Emerg Med 2019; 19:78. [PMID: 31805859 PMCID: PMC6896400 DOI: 10.1186/s12873-019-0291-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Accepted: 11/14/2019] [Indexed: 12/04/2022] Open
Abstract
BACKGROUND Nigeria is ranked second highest in the rate of road accidents and other emergencies (Deaths, disabilities) among 193 countries of the world. There is therefore the need for analyzing Emergency Medical Rescue Services (EMRS) in the country to identify options for improvement. METHOD The study was conducted from February, 2016 to March, 2017 in three EMRS organizations (FRSC, NEMA and MAITAMA Hospital) located in Abuja. The structure, resources, process of EMRS activities and outcome (delay times, case fatality as well as victims and service-providers satisfaction with services) were assessed through observation, time measurements and interviews. RESULTS FRSC and NEMA offers (Road Traffic Injury) RTI and Disaster services, the ambulances consist of Intensive Care Unit(ICU) buses, Helicopters, Speed boats, motorbikes and other specialized vehicles. Mortality and morbidity recorded for 2016 was 1.1 and 2% respectively. MAITAMA is a specialist centre that offers general medical services. A total number 1227(88.8%) lives were saved during the observational period by three organizations, 60(4.9%) deaths, 132 (9.6%) disabilities, 793 (57.2%) NCDs and 593(42.8%) RTI. CONCLUSION Non-communicable diseases (NCDs) cause many deaths and morbidities in the developing world compared to infectious diseases. There is need for total revamping and education of EMRS institutions in Nigeria and Low- Middle Income Countries (LMICs). Abuja and its surroundings suffers from delays in rapid emergency services, lack of adequate awareness, functional ambulances, minimal specialists and inadequate consumables lead to the loss of many lives.
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Affiliation(s)
- Peter Asaga Mac
- Centre for Medicine & Society (Global Health), University Medical Centre Freiburg, 79014 Freiburg, Germany
- Institute of Human Virology, University Medical Centre Freiburg, Freiburg, Germany
| | - Axel Kroeger
- Centre for Medicine & Society (Global Health), University Medical Centre Freiburg, 79014 Freiburg, Germany
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Vandendriessche D, Uribe J, Bertin H, De Geeter F. Performance characteristics of silicon photomultiplier based 15-cm AFOV TOF PET/CT. EJNMMI Phys 2019; 6:8. [PMID: 31076884 PMCID: PMC6510743 DOI: 10.1186/s40658-019-0244-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2018] [Accepted: 04/12/2019] [Indexed: 02/08/2023] Open
Abstract
Background This paper describes the National Electrical Manufacturers Association (NEMA) system performance of the Discovery MI 3-ring PET/CT (GE Healthcare) installed in Bruges, Belgium. This time-of-flight (TOF) PET camera is based on silicon photomultipliers instead of photomultiplier tubes. Methods The NEMA NU2-2012 standard was used to evaluate spatial resolution, sensitivity, image quality (IQ) and count rate curves of the system. Timing and energy resolution were determined. Results Full width at half maximum (FWHM) of spatial resolution in radial, tangential and axial direction was 4.69, 4.08 and 4.68 mm at 1 cm; 5.58, 4.64 and 5.83 mm at 10 cm; and 7.53, 5.08 and 5.47 mm at 20 cm from the centre of the field of view (FOV) for the filtered backprojection reconstruction. For non-TOF ordered subset expectation maximization (OSEM) reconstruction without point spread function (PSF) correction, FWHM was 3.87, 3.69 and 4.15 mm at 1 cm; 4.80, 3.81 and 4.87 mm at 10 cm; and 7.38, 4.16 and 3.98 mm at 20 cm. Sensitivity was 7.258 cps/kBq at the centre of the FOV and 7.117 cps/kBq at 10-cm radial offset. Contrast recovery (CR) using the IQ phantom for the TOF OSEM reconstruction without PSF correction was 47.4, 59.3, 67.0 and 77.0% for the 10-, 13-, 17- and 22-mm radioactive spheres and 82.5 and 85.1% for the 28- and 37-mm non-radioactive spheres. Background variability (BV) was 16.4, 12.1, 9.1, 6.6, 5.1 and 3.8% for the 10-, 13-, 17-, 22-, 28- and 37-mm spheres. Lung error was 8.5%. Peak noise equivalent count rate (NECR) was 102.3 kcps at 23.0 kBq/ml with a scatter fraction of 41.2%. Maximum accuracy error was 3.88%. Coincidence timing resolution was 375.6 ps FWHM. Energy resolution was 9.3% FWHM. Q.Clear reconstruction significantly improved CR and reduced BV compared with OSEM. Conclusion System sensitivity and NECR are lower and IQ phantom’s BV is higher compared with larger axial FOV (AFOV) scanners like the 4-ring discovery MI, as expected from the smaller solid angle of the 3-ring system. The other NEMA performance parameters are all comparable with those of the larger AFOV scanners.
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Affiliation(s)
- Delphine Vandendriessche
- Department of Nuclear Medicine, Algemeen Ziekenhuis Sint-Jan Brugge-Oostende, Ruddershove 10, 8000, Brugge, Belgium
| | - Jorge Uribe
- GE Healthcare, 3000 N Grandview Blvd W-1250, Waukesha, WI, 53188, USA
| | - Hugo Bertin
- GE Healthcare, Kouterveldstraat 20, 1831, Diegem, Belgium
| | - Frank De Geeter
- Department of Nuclear Medicine, Algemeen Ziekenhuis Sint-Jan Brugge-Oostende, Ruddershove 10, 8000, Brugge, Belgium.
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Kaneta T, Ogawa M, Motomura N, Iizuka H, Arisawa T, Hino-Shishikura A, Yoshida K, Inoue T. Initial evaluation of the Celesteion large-bore PET/CT scanner in accordance with the NEMA NU2-2012 standard and the Japanese guideline for oncology FDG PET/CT data acquisition protocol version 2.0. EJNMMI Res 2017; 7:83. [PMID: 29022216 PMCID: PMC5636775 DOI: 10.1186/s13550-017-0331-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Accepted: 10/04/2017] [Indexed: 11/17/2022] Open
Abstract
Background The goal of this study was to evaluate the performance of the Celesteion positron emission tomography/computed tomography (PET/CT) scanner, which is characterized by a large-bore and time-of-flight (TOF) function, in accordance with the NEMA NU-2 2012 standard and version 2.0 of the Japanese guideline for oncology fluorodeoxyglucose PET/CT data acquisition protocol. Spatial resolution, sensitivity, count rate characteristic, scatter fraction, energy resolution, TOF timing resolution, and image quality were evaluated according to the NEMA NU-2 2012 standard. Phantom experiments were performed using 18F-solution and an IEC body phantom of the type described in the NEMA NU-2 2012 standard. The minimum scanning time required for the detection of a 10-mm hot sphere with a 4:1 target-to-background ratio, the phantom noise equivalent count (NECphantom), % background variability (N10mm), % contrast (QH,10mm), and recovery coefficient (RC) were calculated according to the Japanese guideline. Results The measured spatial resolution ranged from 4.5- to 5-mm full width at half maximum (FWHM). The sensitivity and scatter fraction were 3.8 cps/kBq and 37.3%, respectively. The peak noise-equivalent count rate was 70 kcps in the presence of 29.6 kBq mL−1 in the phantom. The system energy resolution was 12.4% and the TOF timing resolution was 411 ps at FWHM. Minimum scanning times of 2, 7, 6, and 2 min per bed position, respectively, are recommended for visual score, noise-equivalent count (NEC)phantom, N10mm, and the QH,10mm to N10mm ratio (QNR) by the Japanese guideline. The RC of a 10-mm-diameter sphere was 0.49, which exceeded the minimum recommended value. Conclusions The Celesteion large-bore PET/CT system had low sensitivity and NEC, but good spatial and time resolution when compared to other PET/CT scanners. The QNR met the recommended values of the Japanese guideline even at 2 min. The Celesteion is therefore thought to provide acceptable image quality with 2 min/bed position acquisition, which is the most common scan protocol in Japan.
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Affiliation(s)
- Tomohiro Kaneta
- Department of Radiology, Yokohama City University, Yokohama, Japan.
| | - Matsuyoshi Ogawa
- Department of Radiology, Yokohama City University, Yokohama, Japan
| | - Nobutoku Motomura
- Nuclear Medicine System Development Department, Toshiba Medical Systems Corporation, Tochigi, Japan
| | - Hitoshi Iizuka
- Department of Radiology, Yokohama City University, Yokohama, Japan
| | - Tetsu Arisawa
- Department of Radiology, Yokohama City University, Yokohama, Japan
| | | | - Keisuke Yoshida
- Department of Radiology, Yokohama City University, Yokohama, Japan
| | - Tomio Inoue
- Department of Radiology, Yokohama City University, Yokohama, Japan
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Hsu DFC, Ilan E, Peterson WT, Uribe J, Lubberink M, Levin CS. Studies of a Next-Generation Silicon-Photomultiplier-Based Time-of-Flight PET/CT System. J Nucl Med 2017; 58:1511-1518. [PMID: 28450566 DOI: 10.2967/jnumed.117.189514] [Citation(s) in RCA: 156] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Accepted: 04/14/2017] [Indexed: 12/21/2022] Open
Abstract
This article presents system performance studies for the Discovery MI PET/CT system, a new time-of-flight system based on silicon photomultipliers. System performance and clinical imaging were compared between this next-generation system and other commercially available PET/CT and PET/MR systems, as well as between different reconstruction algorithms. Methods: Spatial resolution, sensitivity, noise-equivalent counting rate, scatter fraction, counting rate accuracy, and image quality were characterized with the National Electrical Manufacturers Association NU-2 2012 standards. Energy resolution and coincidence time resolution were measured. Tests were conducted independently on two Discovery MI scanners installed at Stanford University and Uppsala University, and the results were averaged. Back-to-back patient scans were also performed between the Discovery MI, Discovery 690 PET/CT, and SIGNA PET/MR systems. Clinical images were reconstructed using both ordered-subset expectation maximization and Q.Clear (block-sequential regularized expectation maximization with point-spread function modeling) and were examined qualitatively. Results: The averaged full widths at half maximum (FWHMs) of the radial/tangential/axial spatial resolution reconstructed with filtered backprojection at 1, 10, and 20 cm from the system center were, respectively, 4.10/4.19/4.48 mm, 5.47/4.49/6.01 mm, and 7.53/4.90/6.10 mm. The averaged sensitivity was 13.7 cps/kBq at the center of the field of view. The averaged peak noise-equivalent counting rate was 193.4 kcps at 21.9 kBq/mL, with a scatter fraction of 40.6%. The averaged contrast recovery coefficients for the image-quality phantom were 53.7, 64.0, 73.1, 82.7, 86.8, and 90.7 for the 10-, 13-, 17-, 22-, 28-, and 37-mm-diameter spheres, respectively. The average photopeak energy resolution was 9.40% FWHM, and the average coincidence time resolution was 375.4 ps FWHM. Clinical image comparisons between the PET/CT systems demonstrated the high quality of the Discovery MI. Comparisons between the Discovery MI and SIGNA showed a similar spatial resolution and overall imaging performance. Lastly, the results indicated significantly enhanced image quality and contrast-to-noise performance for Q.Clear, compared with ordered-subset expectation maximization. Conclusion: Excellent performance was achieved with the Discovery MI, including 375 ps FWHM coincidence time resolution and sensitivity of 14 cps/kBq. Comparisons between reconstruction algorithms and other multimodal silicon photomultiplier and non-silicon photomultiplier PET detector system designs indicated that performance can be substantially enhanced with this next-generation system.
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Affiliation(s)
- David F C Hsu
- Electrical Engineering, Stanford University, Stanford, California.,Radiology, Stanford University, Stanford, California
| | - Ezgi Ilan
- Nuclear Medicine and PET, Department of Surgical Sciences, Uppsala University, Uppsala, Sweden.,Medical Physics, Uppsala University Hospital, Uppsala, Sweden
| | | | | | - Mark Lubberink
- Nuclear Medicine and PET, Department of Surgical Sciences, Uppsala University, Uppsala, Sweden.,Medical Physics, Uppsala University Hospital, Uppsala, Sweden
| | - Craig S Levin
- Electrical Engineering, Stanford University, Stanford, California .,Radiology, Stanford University, Stanford, California.,Physics, Stanford University, Stanford, California; and.,Bioengineering, Stanford University, Stanford, California
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Teoh EJ, McGowan DR, Macpherson RE, Bradley KM, Gleeson FV. Phantom and Clinical Evaluation of the Bayesian Penalized Likelihood Reconstruction Algorithm Q.Clear on an LYSO PET/CT System. J Nucl Med 2015; 56:1447-52. [PMID: 26159585 PMCID: PMC4558942 DOI: 10.2967/jnumed.115.159301] [Citation(s) in RCA: 156] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Accepted: 07/07/2015] [Indexed: 11/16/2022] Open
Abstract
UNLABELLED Q.Clear, a Bayesian penalized-likelihood reconstruction algorithm for PET, was recently introduced by GE Healthcare on their PET scanners to improve clinical image quality and quantification. In this work, we determined the optimum penalization factor (beta) for clinical use of Q.Clear and compared Q.Clear with standard PET reconstructions. METHODS A National Electrical Manufacturers Association image-quality phantom was scanned on a time-of-flight PET/CT scanner and reconstructed using ordered-subset expectation maximization (OSEM), OSEM with point-spread function (PSF) modeling, and the Q.Clear algorithm (which also includes PSF modeling). Q.Clear was investigated for β (B) values of 100-1,000. Contrast recovery (CR) and background variability (BV) were measured from 3 repeated scans, reconstructed with the different algorithms. Fifteen oncology body (18)F-FDG PET/CT scans were reconstructed using OSEM, OSEM PSF, and Q.Clear using B values of 200, 300, 400, and 500. These were visually analyzed by 2 scorers and scored by rank against a panel of parameters (overall image quality; background liver, mediastinum, and marrow image quality; noise level; and lesion detectability). RESULTS As β is increased, the CR and BV decreases; Q.Clear generally gives a higher CR and lower BV than OSEM. For the smallest sphere reconstructed with Q.Clear B400, CR is 28.4% and BV 4.2%, with corresponding values for OSEM of 24.7% and 5.0%. For the largest hot sphere, Q.Clear B400 yields a CR of 75.2% and a BV of 3.8%, with corresponding values for OSEM of 64.4% and 4.0%. Scorer 1 and 2 ranked B400 as the preferred reconstruction in 13 of 15 (87%) and 10 of 15 (73%) cases. The least preferred reconstruction was OSEM PSF in all cases. In most cases, lesion detectability was highest ranked for B200, in 9 of 15 (67%) and 10 of 15 (73%), with OSEM PSF ranked lowest. Poor lesion detectability on OSEM PSF was seen in cases of mildly (18)F-FDG-avid mediastinal nodes in lung cancer and small liver metastases due to background noise. Conversely, OSEM PSF was ranked second highest for lesion detectability in most pulmonary nodule evaluation cases. The combined scores confirmed B400 to be the preferred reconstruction. CONCLUSION Our phantom measurement results demonstrate improved CR and reduced BV when using Q.Clear instead of OSEM. A β value of 400 is recommended for oncology body PET/CT using Q.Clear.
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Affiliation(s)
- Eugene J Teoh
- Department of Radiology, Churchill Hospital, Oxford University Hospitals NHS Trust, Oxford, United Kingdom Department of Oncology, University of Oxford, Old Road Campus Research Building, Oxford, United Kingdom; and
| | - Daniel R McGowan
- Department of Oncology, University of Oxford, Old Road Campus Research Building, Oxford, United Kingdom; and Radiation Physics and Protection, Churchill Hospital, Oxford University Hospitals NHS Trust, Oxford, United Kingdom
| | - Ruth E Macpherson
- Department of Radiology, Churchill Hospital, Oxford University Hospitals NHS Trust, Oxford, United Kingdom
| | - Kevin M Bradley
- Department of Radiology, Churchill Hospital, Oxford University Hospitals NHS Trust, Oxford, United Kingdom
| | - Fergus V Gleeson
- Department of Radiology, Churchill Hospital, Oxford University Hospitals NHS Trust, Oxford, United Kingdom Department of Oncology, University of Oxford, Old Road Campus Research Building, Oxford, United Kingdom; and
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Miyake KK, Matsumoto K, Inoue M, Nakamoto Y, Kanao S, Oishi T, Kawase S, Kitamura K, Yamakawa Y, Akazawa A, Kobayashi T, Ohi J, Togashi K. Performance Evaluation of a New Dedicated Breast PET Scanner Using NEMA NU4-2008 Standards. J Nucl Med 2014; 55:1198-203. [PMID: 24812244 DOI: 10.2967/jnumed.113.131565] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Accepted: 03/17/2014] [Indexed: 11/16/2022] Open
Abstract
UNLABELLED The aim of this work was to evaluate the performance characteristics of a newly developed dedicated breast PET scanner, according to National Electrical Manufacturers Association (NEMA) NU 4-2008 standards. METHODS The dedicated breast PET scanner consists of 4 layers of a 32 × 32 lutetium oxyorthosilicate-based crystal array, a light guide, and a 64-channel position-sensitive photomultiplier tube. The size of a crystal element is 1.44 × 1.44 × 4.5 mm. The detector ring has a large solid angle with a 185-mm aperture and an axial coverage of 155.5 mm. The energy windows at depth of interaction for the first and second layers are 400-800 keV, and those at the third and fourth layers are 100-800 keV. A fixed timing window of 4.5 ns was used for all acquisitions. Spatial resolution, sensitivity, counting rate capabilities, and image quality were evaluated in accordance with NEMA NU 4-2008 standards. Human imaging was performed in addition to the evaluation. RESULTS Radial, tangential, and axial spatial resolution measured as minimal full width at half maximum approached 1.6, 1.7, and 2.0 mm, respectively, for filtered backprojection reconstruction and 0.8, 0.8, and 0.8 mm, respectively, for dynamic row-action maximum-likelihood algorithm reconstruction. The peak absolute sensitivity of the system was 11.2%. Scatter fraction at the same acquisition settings was 30.1% for the rat-sized phantom. Peak noise-equivalent counting rate and peak true rate for the ratlike phantom was 374 kcps at 25 MBq and 603 kcps at 31 MBq, respectively. In the image-quality phantom study, recovery coefficients and uniformity were 0.04-0.82 and 1.9%, respectively, for standard reconstruction mode and 0.09-0.97 and 4.5%, respectively, for enhanced-resolution mode. Human imaging provided high-contrast images with restricted background noise for standard reconstruction mode and high-resolution images for enhanced-resolution mode. CONCLUSION The dedicated breast PET scanner has excellent spatial resolution and high sensitivity. The performance of the dedicated breast PET scanner is considered to be reasonable enough to support its use in breast cancer imaging.
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Affiliation(s)
- Kanae K Miyake
- Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University Hospital, Kyoto, Japan
| | - Keiichi Matsumoto
- Department of Radiological Technology, Kyoto College of Medical Science, Kyoto, Japan
| | - Mika Inoue
- Department of Clinical Radiology Service, Kyoto University Hospital, Kyoto, Japan; and
| | - Yuji Nakamoto
- Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University Hospital, Kyoto, Japan
| | - Shotaro Kanao
- Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University Hospital, Kyoto, Japan
| | - Tae Oishi
- Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University Hospital, Kyoto, Japan
| | - Shigeto Kawase
- Department of Clinical Radiology Service, Kyoto University Hospital, Kyoto, Japan; and
| | - Keishi Kitamura
- Technology Research Laboratory, Shimadzu Corp., Kyoto, Japan
| | | | - Ayako Akazawa
- Technology Research Laboratory, Shimadzu Corp., Kyoto, Japan
| | | | - Junichi Ohi
- Technology Research Laboratory, Shimadzu Corp., Kyoto, Japan
| | - Kaori Togashi
- Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University Hospital, Kyoto, Japan
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Boisson F, Zahra D, Parmar A, Gregoire MC, Meikle SR, Hamse H, Reilhac A. Imaging capabilities of the Inveon SPECT system using single-and multipinhole collimators. J Nucl Med 2013; 54:1833-40. [PMID: 24009279 DOI: 10.2967/jnumed.112.117572] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
UNLABELLED The Inveon small-animal SPECT system comes with several types of multipinhole collimator plates. We evaluate here the performance measurements of the Inveon SPECT system using 6 different collimators: 3 dedicated for mouse imaging and 3 for rat imaging. METHODS The measured performance parameters include the sensitivity, the spatial resolution using line sources, the ultra-micro Derenzo phantom, the recovery coefficient and the noise measurements using the National Electrical Manufacturers Association NU-4 image quality phantom, obtained with the 2 reconstruction algorithms available with the Inveon Acquisition Workplace, version 1.5-the 3-dimensional ordered-subset expectation maximization (3DOSEM) and the 3-dimensional maximum a posteriori (3DMAP). Further, the overall performance of the system is illustrated by an animal experiment. RESULTS The results show that the Inveon SPECT scanner offers a spatial resolution, measured at the center of the field of view, ranging from 0.6 to 1 mm with the collimator plates dedicated to mouse imaging and from 1.2 to less than 2 mm with rat collimator plates. The system sensitivity varies from 29 to 404 cps/MBq for mouse collimators and from 53 to 175 cps/MBq for rat collimators. The image quality study showed that 3DMAP allows better noise reduction while preserving the recovery coefficient, compared with other regularization strategies such as the premature termination of the 3DOSEM reconstruction or 3DOSEM followed by gaussian filtering. CONCLUSION The acquisition parameters, such as the collimator set and the radius of rotation, offer a wide range of possibilities to apply to a large number of biologic studies. However, special care must be taken because this increase in sensitivity can be offset by image degradation, such as image artifacts caused by projection overlap and statistical noise due to a higher number of iterations required for convergence. 3DMAP allowed better noise reduction while maintaining relatively constant recovery coefficients, as compared with other reconstruction strategies.
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Affiliation(s)
- Frederic Boisson
- Australian Nuclear Science and Technology Organisation, New South Wales, Australia; and
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