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Freire M, Gonzalez-Montoro A, Cañizares G, Rezaei A, Nuyts J, Berr SS, Williams MB, Benlloch JM, Gonzalez AJ. Experimental validation of a rodent PET scanner prototype based on a single LYSO crystal tube. IEEE TRANSACTIONS ON RADIATION AND PLASMA MEDICAL SCIENCES 2022; 6:697-706. [PMID: 35909498 PMCID: PMC9328404 DOI: 10.1109/trpms.2021.3124448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/12/2023]
Abstract
Improving sensitivity and spatial resolution in small animal Positron Emission Tomography imaging instrumentation constitutes one of the main goals of nuclear imaging research. These parameters are degraded by the presence of gaps between the detectors. The present manuscript experimentally validates our prototype of an edge-less pre-clinical PET system based on a single LYSO:Ce annulus with an inner diameter of 62 mm and 10 outer facets of 26 × 52 mm2. Scintillation light is read out by arrays of 8 × 8 SiPMs coupled to the facets, using a projection readout of the rows and columns signals. The readout provides accurate Depth of Interaction (DOI). We have implemented a calibration that mitigates the DOI-dependency of the transaxial and axial impact coordinates, and the energy photopeak gain. An energy resolution of 23.4 ± 1.8% was determined. Average spatial resolution of 1.4 ± 0.2 and 1.3 ± 0.4 mm FWHM were achieved for the radial and axial directions, respectively. We found a peak sensitivity of 3.8% at the system center, and a maximum NECR at 40.6 kcps for 0.27 mCi. The image quality was evaluated using reconstructed images of an array of sources and the NEMA image quality phantom was also studied.
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Affiliation(s)
- Marta Freire
- Instituto de Instrumentación para la Imagen Molecular (i3M-CSIC-UPV), Valencia, Spain
| | | | - Gabriel Cañizares
- Instituto de Instrumentación para la Imagen Molecular (i3M-CSIC-UPV), Valencia, Spain
| | - Ahmadreza Rezaei
- Department of Imaging and Pathology, Nuclear Medicine & Molecular imaging, KU Leuven, Leuven, Belgium
| | - Johan Nuyts
- Department of Imaging and Pathology, Nuclear Medicine & Molecular imaging, KU Leuven, Leuven, Belgium
| | - Stuart S Berr
- Department of Radiology and Medical Imaging, The University of Virginia, Charlottesville, Virginia, United States
| | - Mark B Williams
- Department of Radiology and Medical Imaging, The University of Virginia, Charlottesville, Virginia, United States
| | - Jose M Benlloch
- Instituto de Instrumentación para la Imagen Molecular (i3M-CSIC-UPV), Valencia, Spain
| | - Antonio J Gonzalez
- Instituto de Instrumentación para la Imagen Molecular (i3M-CSIC-UPV), Valencia, Spain
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Yoshida E, Obata F, Kamada K, Yoshikawa A, Yamaya T. Development of crosshair light sharing PET detector with TOF and DOI capabilities using fast LGSO scintillator. Phys Med Biol 2021; 66. [PMID: 34644694 DOI: 10.1088/1361-6560/ac2f8b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Accepted: 10/13/2021] [Indexed: 11/12/2022]
Abstract
Objective.Time-of-flight (TOF) and depth-of-interaction (DOI) are well recognized as important information to improve PET image quality. Since such information types are not correlated, many TOF-DOI detectors have been developed but there are only a few reports of high-resolution detectors (e.g. 1.5 mm resolution) for brain PET systems. Based on the DOI detector, which enables single-ended readout by optically coupling a pair of crystals and having a loop structure, we have developed the crosshair light sharing (CLS) PET detector that optically couples the four-loop structure, consisting of quadrisected crystals comparable in size to a photo-sensor, to four photo-sensors in close proximity arranged in a windmill shape. Even as a high-resolution detector, the CLS PET detector could obtain both TOF and DOI information. The coincidence resolving time (CRT) of the CLS PET detector needs to be further improved, however, for application to the brain PET system. Recently, a fast LGSO crystal was developed which has advantages in detection efficiency and CRT compared to the GFAG crystal. In this work, we developed the CLS PET detector using the fast LGSO crystal for the TOF-DOI brain PET system.Approach.The crystals were each 1.45 × 1.45 × 15 mm3and all surfaces were chemically etched. The CLS PET detector consisted of a 14 × 14 crystal array optically coupled to an 8 × 8 MPPC array.Main results.The fast LGSO array provided 10.1% energy resolution at 511 keV, 4.7 mm DOI resolution at 662 keV, and 293 ps CRT with the energy window of 440-620 keV.Significance.The developed CLS PET detector has 290% higher coincidence sensitivity, 30% better energy resolution, and 32% better time resolution compared to our previous CLS PET detector.
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Affiliation(s)
- Eiji Yoshida
- National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Fujino Obata
- National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Kei Kamada
- New Industry Creation Hatchery Center, Tohoku University, Japan
| | - Akira Yoshikawa
- New Industry Creation Hatchery Center, Tohoku University, Japan.,Institute for Materials Research, Tohoku University, Japan
| | - Taiga Yamaya
- National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
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Fast Energy Dependent Scatter Correction for List-Mode PET Data. J Imaging 2021; 7:jimaging7100199. [PMID: 34677285 PMCID: PMC8541469 DOI: 10.3390/jimaging7100199] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 09/20/2021] [Accepted: 09/25/2021] [Indexed: 11/25/2022] Open
Abstract
Improvements in energy resolution of modern positron emission tomography (PET) detectors have created opportunities to implement energy-based scatter correction algorithms. Here, we use the energy information of auxiliary windows to estimate the scatter component. Our method is directly implemented in an iterative reconstruction algorithm, generating a scatter-corrected image without the need for sinograms. The purpose was to implement a fast energy-based scatter correction method on list-mode PET data, when it was not possible to use an attenuation map as a practical approach for the scatter degradation. The proposed method was evaluated using Monte Carlo simulations of various digital phantoms. It accurately estimated the scatter fraction distribution, and improved the image contrast in the simulated studied cases. We conclude that the proposed scatter correction method could effectively correct the scattered events, including multiple scatters and those originated in sources outside the field of view.
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Jaliparthi G, Martone PF, Stolin AV, Raylman RR. Deep residual-convolutional neural networks for event positioning in a monolithic annular PET scanner. Phys Med Biol 2021; 66. [PMID: 34153950 DOI: 10.1088/1361-6560/ac0d0c] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Accepted: 06/21/2021] [Indexed: 11/12/2022]
Abstract
PET scanners based on monolithic pieces of scintillator can potentially produce superior performance characteristics (high spatial resolution and detection sensitivity, for example) compared to conventional PET scanners. Consequently, we initiated development of a preclinical PET system based on a single 7.2 cm long annulus of LYSO, called AnnPET. While this system could facilitate creation of high-quality images, its unique geometry results in optics that can complicate estimation of event positioning in the detector. To address this challenge, we evaluated deep-residual convolutional neural networks (DR-CNN) to estimate the three-dimensional position of annihilation photon interactions. Monte Carlo simulations of the AnnPET scanner were used to replicate the physics, including optics, of the scanner. It was determined that a ten-layer-DR-CNN was most suited to application with AnnPET. The errors between known event positions, and those estimated by this network and those calculated with the commonly used center-of-mass algorithm (COM) were used to assess performance. The mean absolute errors (MAE) for the ten-layer-DR-CNN-based event positions were 0.54 mm, 0.42 mm and 0.45 mm along thex(axial)-,y(transaxial)- andz- (depth-of-interaction) axes, respectively. For COM estimates, the MAEs were 1.22 mm, 1.04 mm and 2.79 mm in thex-,y- andz-directions, respectively. Reconstruction of the network-estimated data with the 3D-FBP algorithm (5 mm source offset) yielded spatial resolutions (full-width-at-half-maximum (FWHM)) of 0.8 mm (radial), 0.7 mm (tangential) and 0.71 mm (axial). Reconstruction of the COM-derived data yielded spatial resolutions (FWHM) of 1.15 mm (radial), 0.96 mm (tangential) and 1.14 mm (axial). These findings demonstrated that use of a ten-layer-DR-CNN with a PET scanner based on a monolithic annulus of scintillator has the potential to produce excellent performance compared to standard analytical methods.
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Affiliation(s)
- Gangadhar Jaliparthi
- Center for Advanced Imaging, Department of Radiology, School of Medicine, West Virginia University, Morgantown, WV, United States of America
| | - Peter F Martone
- Center for Advanced Imaging, Department of Radiology, School of Medicine, West Virginia University, Morgantown, WV, United States of America
| | - Alexander V Stolin
- Center for Advanced Imaging, Department of Radiology, School of Medicine, West Virginia University, Morgantown, WV, United States of America
| | - Raymond R Raylman
- Center for Advanced Imaging, Department of Radiology, School of Medicine, West Virginia University, Morgantown, WV, United States of America
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Gonzalez-Montoro A, Gonzalez AJ, Pourashraf S, Miyaoka RS, Bruyndonckx P, Chinn G, Pierce LA, Levin CS. Evolution of PET Detectors and Event Positioning Algorithms Using Monolithic Scintillation Crystals. IEEE TRANSACTIONS ON RADIATION AND PLASMA MEDICAL SCIENCES 2021. [DOI: 10.1109/trpms.2021.3059181] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Du J, Cherry S. A high resolution and high detection efficiency depth-encoding detector for brain positron emission tomography based on a 0.75 mm pitch scintillator array. JOURNAL OF INSTRUMENTATION : AN IOP AND SISSA JOURNAL 2021; 16:P05015. [PMID: 34925535 PMCID: PMC8681625 DOI: 10.1088/1748-0221/16/05/p05015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The quantitative accuracy and precision of brain positron emission tomography (PET) studies can be considerably improved using dedicated brain PET scanners with a uniform high resolution and a high sensitivity across the brain volume. One approach to building such a system is to construct the PET scanner using depth-of-interaction (DOI) encoding detectors with finely segmented and thick crystal arrays. In this paper, the performance of a DOI PET detector based on two 16 × 16 arrays of 2 × 2 mm2 SiPMs coupled to both ends of a 44 × 44 array of 0.69 × 0.69 × 30 mm3 polished LYSO crystals was evaluated at different temperatures (-9°C, 0°C, 10°C, and 20°C) for brain PET applications. The pitch size of the LYSO array is 0.75 mm. The flood histograms show that all the crystal elements in the LYSO array can be resolved except some edge crystals, due to the limited light sharing. The average energy resolution, average DOI resolution, and average timing resolution across crystal elements are 21.1 ± 3.0%, 3.47 ± 0.17 mm, and 1.38 ± 0.09 ns, respectively, which were obtained at a bias voltage of 56.5 V and a temperature of 0°C.
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Affiliation(s)
- J. Du
- Department of Biomedical Engineering, University of California at Davis, Davis, California 95616, U.S.A
| | - S.R. Cherry
- Department of Biomedical Engineering, University of California at Davis, Davis, California 95616, U.S.A
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Domínguez-Jiménez DY, Alva-Sánchez H. Energy spectra due to the intrinsic radiation of LYSO/LSO scintillators for a wide range of crystal sizes. Med Phys 2021; 48:1596-1607. [PMID: 33475160 DOI: 10.1002/mp.14729] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 10/22/2020] [Accepted: 12/21/2020] [Indexed: 01/02/2023] Open
Abstract
PURPOSE Most detectors in current positron emission tomography (PET) scanners and prototypes use lutetium oxyorthosilicate (LSO) or lutetium yttrium oxyorthosilicate (LYSO) scintillators. The aim of this work is to provide a complete set of background energy spectra, due to the scintillator intrinsic radioactivity, for a wide range of crystal sizes. METHODS An analytical model, developed and validated in a previous work, was used to obtain the background energy spectra of square base cuboids of different dimensions. The model uses the photon absorption probabilities of the three gamma rays (88, 202, and 307 keV) emitted following the beta decay of 176 Lu to 176 Hf excited states. These probabilities were obtained for each crystal size considered in this work from Monte Carlo simulations using the PENELOPE code. The probabilities are then used to normalize and shift the beta spectrum to the corresponding energy value of the simultaneous detection of one, two, or three gamma rays in the scintillator. The simulated cuboids had side lengths of 5, 10, 20, 30, 40, 50, and 60 mm and crystal thickness T = 2.5, 5, 10, 15, and 20 mm. From these results a complete set of energy spectra, including intermediate dimensions, were obtained. In addition, LYSO and LSO were compared in terms of their analytical background energy spectra for two crystal sizes. The analytical spectra were convolved using a variable Gaussian kernel to account for the energy resolution of a typical detector. A parameterization of the photon absorption probabilities for each gamma ray energy as a function of the cuboid volume to surface area ratio was obtained. RESULTS A data set of L(Y)SO background energy spectra was obtained and is available for the reader as 2D histograms. The model accurately predicts the structure of the energy spectra including the relative peak and valley intensities. The data allow visualizing how the structure evolves with increasing crystal length and thickness. Lutetium yttrium oxyorthosilicate and LSO present very similar background energy spectra for the range of sizes studied in this work and therefore the data generated can be confidently used for both scintillator materials. The filtered spectra showed a variable shift in the main peaks, depending on crystal size, alerting that to achieve a correct detector calibration using the background spectrum is not straight forward and requires precise data analysis and measurements. In addition, we found that square base L(Y)SO cuboids with same volume to surface area ratio have background spectra with the same structure. CONCLUSIONS We present the energy spectra of L(Y)SO crystal of different sizes which will be very useful for industry and research groups developing and simulating detectors for positron imaging applications in terms of calibration, quality assurance, crystal maps, detector fine gain tuning, background reduction and other applications using the long-lived 176 Lu source. We analyzed the data produced in this work and found that crystal cuboids with equal volume to surface area ratio produce the same background energy spectra, a conclusion that simplifies its calculation and clarifies why the same energy spectrum is observed under different experimental setups.
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Affiliation(s)
| | - Héctor Alva-Sánchez
- Instituto de Física, Universidad Nacional Autónoma de México, A.P. 20-364, Mexico City, 01000, Mexico
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Kim H, Kao CM, Hua Y, Xie Q, Chen CT. Multiplexing Readout for Time-of-Flight (TOF) PET Detectors Using Striplines. IEEE TRANSACTIONS ON RADIATION AND PLASMA MEDICAL SCIENCES 2021; 5:662-670. [PMID: 34541433 PMCID: PMC8445371 DOI: 10.1109/trpms.2021.3051364] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
A recent trend in PET instrumentation is the use of silicon photomultipliers (SiPMs) for high-resolution and time-of-flight (TOF) detection. Due to its small size, a PET system can use a large number of SiPMs and hence effective and scalable multiplexing readout methods become important. Unfortunately, multiplexing readout generally degrades the fast timing properties necessary for TOF, especially at high channel reduction. Previously, we developed a stripline (SL) based readout method for PET that uses a time-based multiplexing mechanism. This method maintains fast timing by design and has been successfully used for TOF PET detectors. In this paper, we present a more systematic study in which we examine how two important design parameters of the readout - the number of inputs on an SL (n SL) and the pathlength between adjacent input positions (Δℓ) - affect its detection performance properties for PET. Our result shows that, up to n SL = 32 the readout can achieve accurate pixel discrimination and causes little degradation in the energy resolution. The TOF resolution is compromised mildly and a coincidence resolving time on the order of 300 ps FWHM can be achieved for LYSO- and SiPM-based detectors. We also discuss strategies in using the readout to further reduce the number of electronic channels that a PET system would otherwise need.
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Affiliation(s)
- Heejong Kim
- Department of Radiology, University of Chicago, Chicago, IL 60637 USA
| | - Chien-Min Kao
- Department of Radiology, University of Chicago, Chicago, IL 60637 USA
| | - Yuexuan Hua
- Raycan Technology Co., Ltd., Suzhou, Jiangsu 215163, China
| | - Qingguo Xie
- Biomedical Engineering Department, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Chin-Tu Chen
- Department of Radiology, University of Chicago, Chicago, IL 60637 USA
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Freire M, Gonzalez-Montoro A, Cañizares G, Berr SS, Vidal LF, Hernandez L, Gonzalez AJ. Calibration Methodology of an Edgeless PET System Prototype. IEEE NUCLEAR SCIENCE SYMPOSIUM CONFERENCE RECORD. NUCLEAR SCIENCE SYMPOSIUM 2020; 2020:10.1109/NSS/MIC42677.2020.9508042. [PMID: 34908824 PMCID: PMC8667022 DOI: 10.1109/nss/mic42677.2020.9508042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Instrumentation research in small animal Positron Emission Tomography (PET) imaging is driven by improving timing, spatial resolution and sensitivity. Conventional PET scanners are built of multiple detectors placed in a cylindrical geometry with gaps between them in both the transaxial and axial planes. These gaps decrease sensitivity and degrade spatial resolution towards the edges of the system field of view (FOV). To mitigate these problems, we have designed and validated an edgeless pre-clinical PET system based on a single LYSO annulus with an inner diameter of 62 mm and 10 outer facets of 26 × 52 mm2 each. The scintillation light is read out using the row and columns of Silicon Photomultipliers (SiPMs) mounted in magnetic-field compatible PCBs. The objective of this work is to provide a calibration method for this system. The particular design of the annulus produces some undesirable effects in the light distributions (LD) at the module joints, which needs to be addressed. Nevertheless, after calibration, the system allows one to properly retrieve both, the energy and 3D photon impact positions.
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Affiliation(s)
- Marta Freire
- Instituto de Instrumentación para Imagen Molecular (I3M), Centro Mixto CSIC-Universitat Politècnica de València, 46022 Valencia, Spain
| | - Andrea Gonzalez-Montoro
- Instituto de Instrumentación para Imagen Molecular (I3M), Centro Mixto CSIC-Universitat Politècnica de València, 46022 Valencia, Spain
| | - Gabriel Cañizares
- Instituto de Instrumentación para Imagen Molecular (I3M), Centro Mixto CSIC-Universitat Politècnica de València, 46022 Valencia, Spain
| | | | - Luis F Vidal
- Instituto de Instrumentación para Imagen Molecular (I3M), Centro Mixto CSIC-Universitat Politècnica de València, 46022 Valencia, Spain
| | - Liczandro Hernandez
- Instituto de Instrumentación para Imagen Molecular (I3M), Centro Mixto CSIC-Universitat Politècnica de València, 46022 Valencia, Spain
| | - Antonio J Gonzalez
- Instituto de Instrumentación para Imagen Molecular (I3M), Centro Mixto CSIC-Universitat Politècnica de València, 46022 Valencia, Spain
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Du J, Bai X, Cherry SR. A depth-encoding PET detector for high resolution PET using 1 mm SiPMs. Phys Med Biol 2020; 65:165011. [PMID: 32580180 DOI: 10.1088/1361-6560/ab9fc9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
A dual-ended readout PET detector based on two Hamamatsu 16 × 16 arrays of 1 × 1 mm2 SiPMs coupled to both ends of a 25 × 25 array of 0.69 × 0.69 × 20 mm3 polished LYSOs was evaluated in terms of flood histogram, energy resolution, timing resolution, and DOI resolution. The SiPM arrays have a pitch size of 1.2 mm. Each SiPM pixel has an active area of 1 × 1 mm2, and was fabricated using 15 μm microcells. The LYSO array has a pitch size of 0.75 mm, and the crystals are separated using Toray reflector with a thickness of 50 μm. The flood histogram and energy resolution were measured at different overvoltages (ranging from 1.5 to 7.0 V, in 0.5 V steps) and at four different temperatures (-7, 0, 10 and 20 °C). The timing resolution and DOI resolution were obtained at the optimal overvoltage for the flood histogram and at each different temperature. Overall, the results show better performance was obtained at lower temperatures, and that the optimal overvoltage decreased at higher temperatures. The optimal overvoltage was 5.0 V (corresponding to a bias voltage of 68.5 V) in order to achieve the highest quality flood histogram at 0 °C. Under these conditions, the flood histogram quality, energy resolution, timing resolution, and DOI resolution were 3.26 ± 0.65, 18.4 ± 4.5%, 1.70 ± 0.12 ns and 2.22 ± 0.19 mm, respectively. The flood histograms and energy resolution were also obtained at different activities. The results show that better flood histogram and energy resolution were obtained at lower activity, however all the crystals can be resolved at an event rate of over 210 k cps, indicating the DOI detector module can be used both for high resolution human brain PET and small animal PET applications.
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Affiliation(s)
- Junwei Du
- Department of Biomedical Engineering, University of California-Davis, One Shields Avenue, Davis, CA 95616 United States of America
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Abstract
In the light of ever-increasing demands for PET scanner with better resolvability, higher sensitivity and wide accessibility for noninvasive screening of small structures and physiological processes in laboratory rodents, several dedicated PET scanners were developed and evaluated. Understanding conceptual design constraints pros and cons of different configurations and impact of the major components will be helpful to further establish the crucial role of these miniaturized systems in a broad spectrum of modern research. Hence, a comprehensive review of preclinical PET scanners developed till early 2020 with particular emphasis on innovations in instrumentation and geometrical designs is provided.
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Affiliation(s)
- Mahsa Amirrashedi
- Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences, Tehran, Iran; Research Center for Molecular and Cellular Imaging, Tehran University of Medical Sciences, Tehran, Iran
| | - Habib Zaidi
- Division of Nuclear Medicine and Molecular Imaging, Geneva University Hospital, Geneva CH-1211, Switzerland; Geneva University Neurocenter, Geneva University, Geneva CH-1205, Switzerland; Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen 9700 RB, Netherlands; Department of Nuclear Medicine, University of Southern Denmark, Odense 500, Denmark
| | - Mohammad Reza Ay
- Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences, Tehran, Iran; Research Center for Molecular and Cellular Imaging, Tehran University of Medical Sciences, Tehran, Iran.
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Du J, Bai X, Liu CC, Qi J, Cherry SR. Design and evaluation of gapless curved scintillator arrays for simultaneous high-resolution and high-sensitivity brain PET. Phys Med Biol 2019; 64:235004. [PMID: 31618708 DOI: 10.1088/1361-6560/ab4e3c] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Brain PET scanners that simultaneously provide high-resolution across the field-of-view and high-sensitivity can be constructed using detectors based on SiPM arrays coupled to both ends of scintillator arrays with finely segmented and long detector elements. To reduce the dead space between detector modules and hence improve the sensitivity of PET scanners, crystal arrays with curved surfaces are proposed. In this paper, the performance of a proof-of-concept detector module with nine detector submodules based on SiPMs coupled to both ends of a curved LYSO array with a pitch size of 1.0 × 1.0 mm2 at the front-end and a length of 30 mm was evaluated. A simple signal multiplexing method using the shared-photodetector readout method was evaluated to identify the crystals. The results showed that all the LYSO elements in the detector module of interest could be clearly resolved. The energy resolution, depth-of-interaction resolution, and timing resolution were 14.6% ± 3.6%, 2.77 ± 0.39 mm, and 1.15 ± 0.07 ns, respectively, obtained at a bias voltage of 28.0 V and a temperature of 16.8 °C ± 0.2 °C.
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Affiliation(s)
- Junwei Du
- Author to whom correspondence should be addressed
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Mohammadi I, Castro IFC, Correia PMM, Silva ALM, Veloso JFCA. Minimization of parallax error in positron emission tomography using depth of interaction capable detectors: methods and apparatus. Biomed Phys Eng Express 2019. [DOI: 10.1088/2057-1976/ab4a1b] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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