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Correia PMM, Cruzeiro B, Dias J, Encarnação PMCC, Ribeiro FM, Rodrigues CA, Silva ALM. Precise positioning of gamma ray interactions in multiplexed pixelated scintillators using artificial neural networks. Biomed Phys Eng Express 2024; 10:045038. [PMID: 38779912 DOI: 10.1088/2057-1976/ad4f73] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2024] [Accepted: 05/22/2024] [Indexed: 05/25/2024]
Abstract
Introduction. The positioning ofγray interactions in positron emission tomography (PET) detectors is commonly made through the evaluation of the Anger logic flood histograms. machine learning techniques, leveraging features extracted from signal waveform, have demonstrated successful applications in addressing various challenges in PET instrumentation.Aim. This paper evaluates the use of artificial neural networks (NN) forγray interaction positioning in pixelated scintillators coupled to a multiplexed array of silicon photomultipliers (SiPM).Methods. An array of 16 Cerium doped Lutetium-based (LYSO) crystal pixels (cross-section 2 × 2 mm2) coupled to 16 SiPM (S13360-1350) were used for the experimental setup. Data from each of the 16 LYSO pixels was recorded, a total of 160000 events. The detectors were irradiated by 511 keV annihilationγrays from a Sodium-22 (22Na) source. Another LYSO crystal was used for electronic collimation. Features extracted from the signal waveform were used to train the model. Two models were tested: i) single multiple-class neural network (mcNN), with 16 possible outputs followed by a softmax and ii) 16 binary classification neural networks (bNN), each one specialized in identifying events occurred in each position.Results. Both NN models showed a mean positioning accuracy above 85% on the evaluation dataset, although the mcNN is faster to train.DiscussionThe method's accuracy is affected by the introduction of misclassified events that interacted in the neighbour's crystals and were misclassified during the dataset acquisition. Electronic collimation reduces this effect, however results could be improved using a more complex acquisition setup, such as a light-sharing configuration.ConclusionsThe methods comparison showed that mcNN and bNN can surpass the Anger logic, showing the feasibility of using these models in positioning procedures of future multiplexed detector systems in a linear configuration.
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Affiliation(s)
- P M M Correia
- Institute for Nanostructures, Nanomodelling and Nanofabrication (i3N), University of Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal
| | - B Cruzeiro
- Institute for Nanostructures, Nanomodelling and Nanofabrication (i3N), University of Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal
| | - J Dias
- Faculdade de Economia, CeBER, Universidade de Coimbra, Av. Dias da Silva, 165, 3004-512 Coimbra, Portugal
- INESC-Coimbra, Universidade de Coimbra, Rua Sílvio Lima, Pólo II, 3030-290 Coimbra, Portugal
| | - P M C C Encarnação
- Institute for Nanostructures, Nanomodelling and Nanofabrication (i3N), University of Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal
| | - F M Ribeiro
- Institute for Nanostructures, Nanomodelling and Nanofabrication (i3N), University of Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal
| | - C A Rodrigues
- Institute for Nanostructures, Nanomodelling and Nanofabrication (i3N), University of Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal
| | - A L M Silva
- Institute for Nanostructures, Nanomodelling and Nanofabrication (i3N), University of Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal
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Wang F, Kao CM, Zhang X, Liu L, Hua Y, Kim H, Choong WS, Xie Q. DOI- and TOF-capable PET array detector using double-ended light readout and stripline-based row and column electronic readout. IEEE TRANSACTIONS ON RADIATION AND PLASMA MEDICAL SCIENCES 2024; 8:269-276. [PMID: 38654812 PMCID: PMC11034922 DOI: 10.1109/trpms.2024.3360942] [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: 04/26/2024]
Abstract
We investigate a highly multiplexing readout for depth-of-interaction (DOI) and time-of-flight PET detector consisting of an N×N crystals whose light outputs at the front and back ends are detected by using silicon photomultipliers (SiPM). The front N×N SiPM array is read by using a stripline (SL) configured to support discrimination of the row position of the signal-producing crystal. The back N×N SiPM array is similarly read by an SL for column discrimination. Hence, the detector has only four outputs. We built 4×4 and 8×8 detector modules (DM) by using 3.0×3.0×20 mm3 lutetium-yttrium oxyorthosilicates. The outputs were sampled and processed offline. For both DMs, crystal discrimination was successful. For the 4×4 DM, we obtained an average energy resolution (ER) of 14.1%, an average DOI resolution of 2.5 mm, a non DOI-corrected coincidence resolving time (CRT), measured in coincidence with a single-pixel reference detector, of about 495 ps. For the 8×8 DM, the average ER, average DOI resolution and average CRT were 16.4%, 2.9 mm, and 641 ps, respectively. We identified the intercrystal scattering as a probable cause for the CRT deterioration when the DM was increased from 4×4 to 8×8.
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Affiliation(s)
- Fei Wang
- College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | | | - Xiaoyu Zhang
- Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, China
| | - Linfeng Liu
- College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | | | - Heejong Kim
- The University of Chicago, Chicago, Illinois, USA
| | - Woon-Seng Choong
- Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Qingguo Xie
- College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
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Li Y, LaBella A, Zeng X, Wang Z, Petersen E, Cao X, Zhao W, Goldan AH. Interleaved signal multiplexing readout in depth encoding Prism-PET detectors. Med Phys 2023; 50:4234-4243. [PMID: 37191309 PMCID: PMC11057968 DOI: 10.1002/mp.16456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Revised: 03/01/2023] [Accepted: 03/29/2023] [Indexed: 05/17/2023] Open
Abstract
BACKGROUND Given the large number of readout pixels in clinical positron emission tomography (PET) scanners, signal multiplexing is an indispensable feature to reduce scanner complexity, power consumption, heat output, and cost. PURPOSE In this paper, we introduce interleaved multiplexing (iMux) scheme that utilizes the characteristic light-sharing pattern of depth-encoding Prism-PET detector modules with single-ended readout. METHODS In the iMux readout, four anodes from every other silicon photomultiplier (SiPM) pixels across rows and columns, which overlap with four distinct light guides, are connected to the same application-specific integrated circuit (ASIC) channel. The 4-to-1 coupled Prism-PET detector module was used which consisted of a 16 × 16 array of 1.5 × 1.5 × 20 mm3 lutetium yttrium oxyorthosilicate (LYSO) scintillator crystals coupled to an 8 × 8 array with 3 × 3 mm2 SiPM pixels. A deep learning-based demultiplexing model was investigated to recover the encoded energy signals. Two different experiments were performed with non-multiplexed and multiplexed readouts to evaluate the spatial, depth of interaction (DOI), and timing resolutions of our proposed iMux scheme. RESULTS The measured flood histograms, using the decoded energy signals from our deep learning-based demultiplexing architecture, achieved perfect crystal identification of events with negligible decoding error. The average energy, DOI, and timing resolutions were 9.6 ± 1.5%, 2.9 ± 0.9 mm, and 266 ± 19 ps for non-multiplexed readout and 10.3 ± 1.6%, 2.8 ± 0.8 mm, and 311 ± 28 ps for multiplexed readout, respectively. CONCLUSIONS Our proposed iMux scheme improves on the already cost-effective and high-resolution Prism-PET detector module and provides 16-to-1 crystal-to-readout multiplexing without appreciable performance degradation. Also, only four SiPM pixels are shorted together in the 8 × 8 array to achieve 4-to-1 pixel-to-readout multiplexing, resulting in lower capacitance per multiplexed channel.
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Affiliation(s)
- Yixin Li
- Department of Electrical and Computer Engineering, College of Engineering and Applied Sciences, Stony Brook University, Stony Brook, NY, US
| | - Andy LaBella
- Department of Radiology, Boston Children’s Hospital, Boston, MA, US
| | - Xinjie Zeng
- Department of Electrical and Computer Engineering, College of Engineering and Applied Sciences, Stony Brook University, Stony Brook, NY, US
| | - Zipai Wang
- Department of Biomedical Engineering, College of Engineering and Applied Sciences, Stony Brook University, Stony Brook, NY, US
| | - Eric Petersen
- Department of Biomedical Engineering, College of Engineering and Applied Sciences, Stony Brook University, Stony Brook, NY, US
| | - Xinjie Cao
- Department of Electrical and Computer Engineering, College of Engineering and Applied Sciences, Stony Brook University, Stony Brook, NY, US
| | - Wei Zhao
- Department of Radiology, Renaissance School of Medicine, Stony Brook University, Stony Brook, NY, US
| | - Amir H. Goldan
- Department of Radiology, Weill Cornell Medical College, Cornell University, New York, NY, US
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Park H, Yi M, Lee JS. Silicon photomultiplier signal readout and multiplexing techniques for positron emission tomography: a review. Biomed Eng Lett 2022; 12:263-283. [PMID: 35892029 PMCID: PMC9308856 DOI: 10.1007/s13534-022-00234-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 05/21/2022] [Accepted: 05/30/2022] [Indexed: 12/03/2022] Open
Abstract
In recent years, silicon photomultiplier (SiPM) is replacing the photomultiplier tube (PMT) in positron emission tomography (PET) systems due to its superior properties, such as fast single-photon timing response, small gap between adjacent photosensitive pixels in the array, and insensitivity to magnetic fields. One of the technical challenges when developing SiPM-based PET systems or other position-sensitive radiation detectors is the large number of output channels coming from the SiPM array. Therefore, various signal multiplexing methods have been proposed to reduce the number of output channels and the load on the subsequent data acquisition (DAQ) system. However, the large PN-junction capacitance and quenching resistance of the SiPM yield undesirable resistance–capacitance delay when multiple SiPMs are combined, which subsequently causes the accumulation of dark counts and signal fluctuation of SiPMs. Therefore, without proper SiPM signal handling and processing, the SiPMs may yield worse timing characteristics than the PMTs. This article reviews the evolution of signal readout and multiplexing methods for the SiPM. In this review, we focus primarily on analog electronics for SiPM signal multiplexing, which allows for the reduction of DAQ channels required for the SiPM-based position-sensitive detectors used in PET and other radiation detector systems. Although the applications of most technologies described in the article are not limited to PET systems, the review highlights efforts to improve the physical performance (e.g. spatial, energy, and timing resolutions) of PET detectors and systems.
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Affiliation(s)
- Haewook Park
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, 03080 South Korea
- Department of Nuclear Medicine, Seoul National University College of Medicine, 101, Daehak-ro, Jongno-gu, Seoul, 03080 South Korea
| | - Minseok Yi
- Department of Nuclear Medicine, Seoul National University College of Medicine, 101, Daehak-ro, Jongno-gu, Seoul, 03080 South Korea
- Interdisciplinary Program in Bioengineering, Seoul National University College of Engineering, Seoul, 03080 South Korea
- Integrated Major in Innovative Medical Science, Seoul National University College of Engineering, Seoul, 03080 South Korea
| | - Jae Sung Lee
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, 03080 South Korea
- Department of Nuclear Medicine, Seoul National University College of Medicine, 101, Daehak-ro, Jongno-gu, Seoul, 03080 South Korea
- Interdisciplinary Program in Bioengineering, Seoul National University College of Engineering, Seoul, 03080 South Korea
- Integrated Major in Innovative Medical Science, Seoul National University College of Engineering, Seoul, 03080 South Korea
- Brightonix Imaging Inc, Seoul, 04782 South Korea
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Kim Y, Choi Y, Kim KB, Leem H, Jung JH. Serial line multiplexing method based on bipolar pulse for PET. NUCLEAR ENGINEERING AND TECHNOLOGY 2021. [DOI: 10.1016/j.net.2021.05.032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Schaart DR, Schramm G, Nuyts J, Surti S. Time of Flight in Perspective: Instrumental and Computational Aspects of Time Resolution in Positron Emission Tomography. IEEE TRANSACTIONS ON RADIATION AND PLASMA MEDICAL SCIENCES 2021; 5:598-618. [PMID: 34553105 PMCID: PMC8454900 DOI: 10.1109/trpms.2021.3084539] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The first time-of-flight positron emission tomography (TOF-PET) scanners were developed as early as in the 1980s. However, the poor light output and low detection efficiency of TOF-capable detectors available at the time limited any gain in image quality achieved with these TOF-PET scanners over the traditional non-TOF PET scanners. The discovery of LSO and other Lu-based scintillators revived interest in TOF-PET and led to the development of a second generation of scanners with high sensitivity and spatial resolution in the mid-2000s. The introduction of the silicon photomultiplier (SiPM) has recently yielded a third generation of TOF-PET systems with unprecedented imaging performance. Parallel to these instrumentation developments, much progress has been made in the development of image reconstruction algorithms that better utilize the additional information provided by TOF. Overall, the benefits range from a reduction in image variance (SNR increase), through allowing joint estimation of activity and attenuation, to better reconstructing data from limited angle systems. In this work, we review these developments, focusing on three broad areas: 1) timing theory and factors affecting the time resolution of a TOF-PET system; 2) utilization of TOF information for improved image reconstruction; and 3) quantification of the benefits of TOF compared to non-TOF PET. Finally, we offer a brief outlook on the TOF-PET developments anticipated in the short and longer term. Throughout this work, we aim to maintain a clinically driven perspective, treating TOF as one of multiple (and sometimes competitive) factors that can aid in the optimization of PET imaging performance.
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Affiliation(s)
- Dennis R Schaart
- Section Medical Physics & Technology, Radiation Science and Technology Department, Delft University of Technology, 2629 JB Delft, The Netherlands
| | - Georg Schramm
- Department of Imaging and Pathology, Division of Nuclear Medicine, KU/UZ Leuven, 3000 Leuven, Belgium
| | - Johan Nuyts
- Department of Imaging and Pathology, Division of Nuclear Medicine, KU/UZ Leuven, 3000 Leuven, Belgium
| | - Suleman Surti
- Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104 USA
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Schaart DR. Physics and technology of time-of-flight PET detectors. Phys Med Biol 2021; 66. [PMID: 33711831 DOI: 10.1088/1361-6560/abee56] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Accepted: 03/12/2021] [Indexed: 01/04/2023]
Abstract
The imaging performance of clinical positron emission tomography (PET) systems has evolved impressively during the last ∼15 years. A main driver of these improvements has been the introduction of time-of-flight (TOF) detectors with high spatial resolution and detection efficiency, initially based on photomultiplier tubes, later silicon photomultipliers. This review aims to offer insight into the challenges encountered, solutions developed, and lessons learned during this period. Detectors based on fast, bright, inorganic scintillators form the scope of this work, as these are used in essentially all clinical TOF-PET systems today. The improvement of the coincidence resolving time (CRT) requires the optimization of the entire detection chain and a sound understanding of the physics involved facilitates this effort greatly. Therefore, the theory of scintillation detector timing is reviewed first. Once the fundamentals have been set forth, the principal detector components are discussed: the scintillator and the photosensor. The parameters that influence the CRT are examined and the history, state-of-the-art, and ongoing developments are reviewed. Finally, the interplay between these components and the optimization of the overall detector design are considered. Based on the knowledge gained to date, it appears feasible to improve the CRT from the values of 200-400 ps achieved by current state-of-the-art TOF-PET systems to about 100 ps or less, even though this may require the implementation of advanced methods such as time resolution recovery. At the same time, it appears unlikely that a system-level CRT in the order of ∼10 ps can be reached with conventional scintillation detectors. Such a CRT could eliminate the need for conventional tomographic image reconstruction and a search for new approaches to timestamp annihilation photons with ultra-high precision is therefore warranted. While the focus of this review is on timing performance, it attempts to approach the topic from a clinically driven perspective, i.e. bearing in mind that the ultimate goal is to optimize the value of PET in research and (personalized) medicine.
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Affiliation(s)
- Dennis R Schaart
- Delft University of Technology, Radiation Science & Technology dept., section Medical Physics & Technology, Mekelweg 15, 2629 JB Delft, The Netherlands
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Evaluation of Large-Area Silicon Photomultiplier Arrays for Positron Emission Tomography Systems. ELECTRONICS 2021. [DOI: 10.3390/electronics10060698] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
An individual readout of silicon photomultipliers (SiPMs) would enhance the performance of modern positron emission tomography (PET) systems. However, as it difficult to achieve in practice, a multiplexing readout of SiPM arrays could be performed instead. In this study, we characterized the performance of three PET detector modules utilizing three different SiPM models with active areas of 3 × 3, 4 × 4, and 6 × 6 mm2. Each SiPM array was coupled with a 4 × 4 LYSO crystal block. For SiPM multiplexing, we used a discretized positioning circuit to obtain position and energy information, and applied a first-order capacitive high-pass filter to enhance the time-of-flight measurement capability of the PET detector. The energy performance was similar among the three different SiPM arrays, with an energy resolution of 10%–11%. The best timing performance was achieved with the SiPM array with an active area of 6 × 6 mm2, which yielded a coincidence timing resolution (CTR) value of 401 ps FWHM when an analog high-pass filter was applied. We expect that, in combination with high-performance SiPM multiplexing techniques, the SiPM array with an active area of 6 × 6 mm2 can provide a cost-effective solution for developing a whole-body PET scanner.
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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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Moskal P, Kisielewska D, Y Shopa R, Bura Z, Chhokar J, Curceanu C, Czerwiński E, Dadgar M, Dulski K, Gajewski J, Gajos A, Gorgol M, Del Grande R, C Hiesmayr B, Jasińska B, Kacprzak K, Kamińska A, Kapłon Ł, Karimi H, Korcyl G, Kowalski P, Krawczyk N, Krzemień W, Kozik T, Kubicz E, Małczak P, Mohammed M, Niedźwiecki S, Pałka M, Pawlik-Niedźwiecka M, Pędziwiatr M, Raczyński L, Raj J, Ruciński A, Sharma S, Shivani S, Silarski M, Skurzok M, Stępień EŁ, Vandenberghe S, Wiślicki W, Zgardzińska B. Performance assessment of the 2 γpositronium imaging with the total-body PET scanners. EJNMMI Phys 2020; 7:44. [PMID: 32607664 PMCID: PMC7326848 DOI: 10.1186/s40658-020-00307-w] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Accepted: 05/17/2020] [Indexed: 02/01/2023] Open
Abstract
Purpose In living organisms, the positron-electron annihilation (occurring during the PET imaging) proceeds in about 30% via creation of a metastable ortho-positronium atom. In the tissue, due to the pick-off and conversion processes, over 98% of ortho-positronia annihilate into two 511 keV photons. In this article, we assess the feasibility for reconstruction of the mean ortho-positronium lifetime image based on annihilations into two photons. The main objectives of this work include the (i) estimation of the sensitivity of the total-body PET scanners for the ortho-positronium mean lifetime imaging using 2γ annihilations and (ii) estimation of the spatial and time resolution of the ortho-positronium image as a function of the coincidence resolving time (CRT) of the scanner. Methods Simulations are conducted assuming that radiopharmaceutical is labeled with 44Sc isotope emitting one positron and one prompt gamma. The image is reconstructed on the basis of triple coincidence events. The ortho-positronium lifetime spectrum is determined for each voxel of the image. Calculations were performed for cases of total-body detectors build of (i) LYSO scintillators as used in the EXPLORER PET and (ii) plastic scintillators as anticipated for the cost-effective total-body J-PET scanner. To assess the spatial and time resolution, the four cases were considered assuming that CRT is equal to 500 ps, 140 ps, 50 ps, and 10 ps. Results The estimated total-body PET sensitivity for the registration and selection of image forming triple coincidences (2γ+γprompt) is larger by a factor of 13.5 (for LYSO PET) and by factor of 5.2 (for plastic PET) with respect to the sensitivity for the standard 2γ imaging by LYSO PET scanners with AFOV = 20 cm. The spatial resolution of the ortho-positronium image is comparable with the resolution achievable when using TOF-FBP algorithms already for CRT = 50 ps. For the 20-min scan, the resolution better than 20 ps is expected for the mean ortho-positronium lifetime image determination. Conclusions Ortho-positronium mean lifetime imaging based on the annihilations into two photons and prompt gamma is shown to be feasible with the advent of the high sensitivity total-body PET systems and time resolution of the order of tens of picoseconds.
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Affiliation(s)
- P Moskal
- Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, prof. Stanisława Łojasiewicza 11, Cracow, 30-348, Poland.
| | - D Kisielewska
- Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, prof. Stanisława Łojasiewicza 11, Cracow, 30-348, Poland.
| | - R Y Shopa
- Department of Complex Systems, National Centre for Nuclear Research, Otwock-Świerk, 05-400, Poland
| | - Z Bura
- Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, prof. Stanisława Łojasiewicza 11, Cracow, 30-348, Poland
| | - J Chhokar
- Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, prof. Stanisława Łojasiewicza 11, Cracow, 30-348, Poland
| | - C Curceanu
- INFN, Laboratori Nazionali di Frascati, Frascati, 00044, Italy
| | - E Czerwiński
- Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, prof. Stanisława Łojasiewicza 11, Cracow, 30-348, Poland
| | - M Dadgar
- Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, prof. Stanisława Łojasiewicza 11, Cracow, 30-348, Poland
| | - K Dulski
- Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, prof. Stanisława Łojasiewicza 11, Cracow, 30-348, Poland
| | - J Gajewski
- Institute of Nuclear Physics PAN, Cracow, Poland
| | - A Gajos
- Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, prof. Stanisława Łojasiewicza 11, Cracow, 30-348, Poland
| | - M Gorgol
- Institute of Physics, Maria Curie-Skłodowska University, Lublin, 20-031, Poland
| | - R Del Grande
- INFN, Laboratori Nazionali di Frascati, Frascati, 00044, Italy
| | - B C Hiesmayr
- Faculty of Physics, University of Vienna, Vienna, 1090, Austria
| | - B Jasińska
- Institute of Physics, Maria Curie-Skłodowska University, Lublin, 20-031, Poland
| | - K Kacprzak
- Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, prof. Stanisława Łojasiewicza 11, Cracow, 30-348, Poland
| | - A Kamińska
- Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, prof. Stanisława Łojasiewicza 11, Cracow, 30-348, Poland
| | - Ł Kapłon
- Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, prof. Stanisława Łojasiewicza 11, Cracow, 30-348, Poland
| | - H Karimi
- Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, prof. Stanisława Łojasiewicza 11, Cracow, 30-348, Poland
| | - G Korcyl
- Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, prof. Stanisława Łojasiewicza 11, Cracow, 30-348, Poland
| | - P Kowalski
- Department of Complex Systems, National Centre for Nuclear Research, Otwock-Świerk, 05-400, Poland
| | - N Krawczyk
- Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, prof. Stanisława Łojasiewicza 11, Cracow, 30-348, Poland
| | - W Krzemień
- High Energy Physics Division, National Centre for Nuclear Research, Otwock-Świerk, 05-400, Poland
| | - T Kozik
- Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, prof. Stanisława Łojasiewicza 11, Cracow, 30-348, Poland
| | - E Kubicz
- Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, prof. Stanisława Łojasiewicza 11, Cracow, 30-348, Poland
| | - P Małczak
- 2nd Department of General Surgery, Jagiellonian University Medical College, Cracow, Poland
| | - M Mohammed
- Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, prof. Stanisława Łojasiewicza 11, Cracow, 30-348, Poland.,Department of Physics, College of Education for Pure Sciences, University of Mosul, Mosul, Iraq
| | - Sz Niedźwiecki
- Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, prof. Stanisława Łojasiewicza 11, Cracow, 30-348, Poland
| | - M Pałka
- Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, prof. Stanisława Łojasiewicza 11, Cracow, 30-348, Poland
| | - M Pawlik-Niedźwiecka
- Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, prof. Stanisława Łojasiewicza 11, Cracow, 30-348, Poland
| | - M Pędziwiatr
- 2nd Department of General Surgery, Jagiellonian University Medical College, Cracow, Poland
| | - L Raczyński
- Department of Complex Systems, National Centre for Nuclear Research, Otwock-Świerk, 05-400, Poland
| | - J Raj
- Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, prof. Stanisława Łojasiewicza 11, Cracow, 30-348, Poland
| | - A Ruciński
- Institute of Nuclear Physics PAN, Cracow, Poland
| | - S Sharma
- Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, prof. Stanisława Łojasiewicza 11, Cracow, 30-348, Poland
| | - S Shivani
- Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, prof. Stanisława Łojasiewicza 11, Cracow, 30-348, Poland
| | - M Silarski
- Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, prof. Stanisława Łojasiewicza 11, Cracow, 30-348, Poland
| | - M Skurzok
- Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, prof. Stanisława Łojasiewicza 11, Cracow, 30-348, Poland.,INFN, Laboratori Nazionali di Frascati, Frascati, 00044, Italy
| | - E Ł Stępień
- Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, prof. Stanisława Łojasiewicza 11, Cracow, 30-348, Poland
| | - S Vandenberghe
- Department of Electronics and Information Systems, MEDISIP, Ghent University-IBiTech, De Pintelaan 185 block B, Ghent, B-9000, Belgium
| | - W Wiślicki
- High Energy Physics Division, National Centre for Nuclear Research, Otwock-Świerk, 05-400, Poland
| | - B Zgardzińska
- Institute of Physics, Maria Curie-Skłodowska University, Lublin, 20-031, Poland
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11
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Highly multiplexed SiPM signal readout for brain-dedicated TOF-DOI PET detectors. Phys Med 2019; 68:117-123. [DOI: 10.1016/j.ejmp.2019.11.016] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Revised: 11/12/2019] [Accepted: 11/18/2019] [Indexed: 12/22/2022] Open
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12
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Ko GB, Lee JS. Time-based signal sampling using sawtooth-shaped threshold. ACTA ACUST UNITED AC 2019; 64:125020. [DOI: 10.1088/1361-6560/ab1f23] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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13
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Won JY, Lee JS. Highly Integrated FPGA-Only Signal Digitization Method Using Single-Ended Memory Interface Input Receivers for Time-of-Flight PET Detectors. IEEE TRANSACTIONS ON BIOMEDICAL CIRCUITS AND SYSTEMS 2018; 12:1401-1409. [PMID: 30113901 DOI: 10.1109/tbcas.2018.2865581] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We propose a new highly integrated field-programm-able gate array (FPGA) only signal digitization method for individual signal digitization of time-of-flight positron emission tomography (TOF PET). We configured I/O port of the FPGA with a single-ended memory interface (SeMI) input receiver. The SeMI is a single-ended voltage-referenced interface that has a common reference voltage per I/O Bank, such that each SeMI input receiver can serve as a voltage comparator. The FPGA-only digitizer that uses the single-ended input receivers does not require a separate digitizing integrated chip, and can obtain twice as many signals as that using LVDS input receivers. We implemented a highly integrated digitizer consisting of 82 energy and 82 timing channels using a 28-nm FPGA. The energy and arrival time were measured using a 625-ps binary counter, and a 10-ps time-to-digital converter (TDC), respectively. We first measured the intrinsic characteristics of the proposed FPGA-only digitizer. The SeMI input receiver functioned as the voltage comparator without undesirable offset voltage. The standard deviation value of the time difference measured using two SeMI input receivers with respective TDCs was less than 14.6 ps RMS. In addition, we fed signals from the TOF PET detectors to the SeMI input receivers directly and collected data. The TOF PET detector consisted of a 3 × 3 × 20 mm3 LYSO crystal coupled with a silicon photomultiplier. The energy resolutions were 7.7% and 7.1% for two TOF PET detectors. The coincidence resolving time was 204 ps full width at half maximum. The SeMI digitizer with a high-performance signal digitizer, processor, and high-speed transceivers provides a compact all-in-one data acquisition system.
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14
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Cates JW, Bieniosek MF, Levin CS. Highly multiplexed signal readout for a time-of-flight positron emission tomography detector based on silicon photomultipliers. J Med Imaging (Bellingham) 2017; 4:011012. [PMID: 28382312 DOI: 10.1117/1.jmi.4.1.011012] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2016] [Accepted: 03/09/2017] [Indexed: 11/14/2022] Open
Abstract
Maintaining excellent timing resolution in the generation of silicon photomultiplier (SiPM)-based time-of-flight positron emission tomography (TOF-PET) systems requires a large number of high-speed, high-bandwidth electronic channels and components. To minimize the cost and complexity of a system's back-end architecture and data acquisition, many analog signals are often multiplexed to fewer channels using techniques that encode timing, energy, and position information. With progress in the development SiPMs having lower dark noise, after pulsing, and cross talk along with higher photodetection efficiency, a coincidence timing resolution (CTR) well below 200 ps FWHM is now easily achievable in single pixel, bench-top setups using 20-mm length, lutetium-based inorganic scintillators. However, multiplexing the output of many SiPMs to a single channel will significantly degrade CTR without appropriate signal processing. We test the performance of a PET detector readout concept that multiplexes 16 SiPMs to two channels. One channel provides timing information with fast comparators, and the second channel encodes both position and energy information in a time-over-threshold-based pulse sequence. This multiplexing readout concept was constructed with discrete components to process signals from a [Formula: see text] array of SensL MicroFC-30035 SiPMs coupled to [Formula: see text] Lu1.8Gd0.2SiO5 (LGSO):Ce (0.025 mol. %) scintillators. This readout method yielded a calibrated, global energy resolution of 15.3% FWHM at 511 keV with a CTR of [Formula: see text] FWHM between the 16-pixel multiplexed detector array and a [Formula: see text] LGSO-SiPM reference detector. In summary, results indicate this multiplexing scheme is a scalable readout technique that provides excellent coincidence timing performance.
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Affiliation(s)
- Joshua W Cates
- Stanford University , Department of Radiology, Stanford, California, United States
| | - Matthew F Bieniosek
- Stanford University , Department of Radiology, Stanford, California, United States
| | - Craig S Levin
- Stanford University, Department of Radiology, Stanford, California, United States; Stanford University, Department of Bioengineering, Stanford, California, United States; Stanford University, Department of Physics, Stanford, California, United States; Stanford University, Department of Electrical Engineering, Stanford, California, United States
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15
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Bieniosek MF, Cates JW, Levin CS. A multiplexed TOF and DOI capable PET detector using a binary position sensitive network. Phys Med Biol 2016; 61:7639-7651. [PMID: 27740946 DOI: 10.1088/0031-9155/61/21/7639] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Time of flight (TOF) and depth of interaction (DOI) capabilities can significantly enhance the quality and uniformity of positron emission tomography (PET) images. Many proposed TOF/DOI PET detectors require complex readout systems using additional photosensors, active cooling, or waveform sampling. This work describes a high performance, low complexity, room temperature TOF/DOI PET module. The module uses multiplexed timing channels to significantly reduce the electronic readout complexity of the PET detector while maintaining excellent timing, energy, and position resolution. DOI was determined using a two layer light sharing scintillation crystal array with a novel binary position sensitive network. A 20 mm effective thickness LYSO crystal array with four 3 mm × 3 mm silicon photomultipliers (SiPM) read out by a single timing channel, one energy channel and two position channels achieved a full width half maximum (FWHM) coincidence time resolution of 180 ± 2 ps with 10 mm of DOI resolution and 11% energy resolution. With sixteen 3 mm × 3 mm SiPMs read out by a single timing channel, one energy channel and four position channels a coincidence time resolution 204 ± 1 ps was achieved with 10 mm of DOI resolution and 15% energy resolution. The methods presented here could significantly simplify the construction of high performance TOF/DOI PET detectors.
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Affiliation(s)
- M F Bieniosek
- Department of Radiology, Stanford University, Stanford, CA 94305, USA. Molecular Imaging Program at Stanford (MIPS), Stanford, CA 94305, USA. Department of Electrical Engineering, Stanford University, Stanford, CA 94305, USA
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