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Yoshida E, Yamaya T. PET detectors with depth-of-interaction and time-of-flight capabilities. Radiol Phys Technol 2024; 17:596-609. [PMID: 38888821 DOI: 10.1007/s12194-024-00821-x] [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: 05/07/2024] [Revised: 06/09/2024] [Accepted: 06/09/2024] [Indexed: 06/20/2024]
Abstract
In positron emission tomography (PET), measurements of depth-of-interaction (DOI) information and time-of-flight (TOF) information are important. DOI information reduces the parallax error, and TOF information reduces noise by measuring the arrival time difference of the annihilation photons. Historically, these have been studied independently, and there has been less implementation of both DOI and TOF capabilities because previous DOI detectors did not have good TOF resolution. However, recent improvements in PET detector performance have resulted in commercial PET scanners achieving a coincidence resolving time of around 200 ps, which result in an effect even for small objects. This means that TOF information can now be utilized even for a brain PET scanner, which also requires DOI information. Therefore, various methods have been proposed to obtain better DOI and TOF information. In addition, the cost of PET detectors is also an important factor to consider, since several hundred detectors are used per PET scanner. In this paper, we review the latest DOI-TOF detectors including the history of detector development. When put into practical use, these DOI-TOF detectors are expected to contribute to the improvement of imaging performance in brain PET scanners.
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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.
| | - Taiga Yamaya
- National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba, 263-8555, Japan
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Lan W, Sari H, Rominger A, Fougère CL, Schmidt FP. Optimization and impact of sensitivity mode on abbreviated scan protocols with population-based input function for parametric imaging of [ 18F]-FDG for a long axial FOV PET scanner. Eur J Nucl Med Mol Imaging 2024; 51:3346-3359. [PMID: 38763962 PMCID: PMC11368996 DOI: 10.1007/s00259-024-06745-3] [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: 02/05/2024] [Accepted: 04/28/2024] [Indexed: 05/21/2024]
Abstract
BACKGROUND The long axial field of view, combined with the high sensitivity of the Biograph Vision Quadra PET/CT scanner enables the precise deviation of an image derived input function (IDIF) required for parametric imaging. Traditionally, this requires an hour-long dynamic PET scan for [18F]-FDG, which can be significantly reduced by using a population-based input function (PBIF). In this study, we expand these examinations and include the scanner's ultra-high sensitivity (UHS) mode in comparison to the high sensitivity (HS) mode and evaluate the potential for further shortening of the scan time. METHODS Patlak Ki and DV estimates were determined by the indirect and direct Patlak methods using dynamic [18F]-FDG data of 6 oncological patients with 26 lesions (0-65 min p.i.). Both sensitivity modes for different number/duration of PET data frames were compared, together with the potential of using abbreviated scan durations of 20, 15 and 10 min by using a PBIF. The differences in parametric images and tumour-to-background ratio (TBR) due to the shorter scans using the PBIF method and between the sensitivity modes were assessed. RESULTS A difference of 3.4 ± 7.0% (Ki) and 1.2 ± 2.6% (DV) was found between both sensitivity modes using indirect Patlak and the full IDIF (0-65 min). For the abbreviated protocols and indirect Patlak, the UHS mode resulted in a lower bias and higher precision, e.g., 45-65 min p.i. 3.8 ± 4.4% (UHS) and 6.4 ± 8.9% (HS), allowing shorter scan protocols, e.g. 50-65 min p.i. 4.4 ± 11.2% (UHS) instead of 7.3 ± 20.0% (HS). The variation of Ki and DV estimates for both Patlak methods was comparable, e.g., UHS mode 3.8 ± 4.4% and 2.7 ± 3.4% (Ki) and 14.4 ± 2.7% and 18.1 ± 7.5% (DV) for indirect and direct Patlak, respectively. Only a minor impact of the number of Patlak frames was observed for both sensitivity modes and Patlak methods. The TBR obtained with direct Patlak and PBIF was not affected by the sensitivity mode, was higher than that derived from the SUV image (6.2 ± 3.1) and degraded from 20.2 ± 12.0 (20 min) to 10.6 ± 5.4 (15 min). Ki and DV estimate images showed good agreement (UHS mode, RC: 6.9 ± 2.3% (Ki), 0.1 ± 3.1% (DV), peak signal-to-noise ratio (PSNR): 64.5 ± 3.3 dB (Ki), 61.2 ± 10.6 dB (DV)) even for abbreviated scan protocols of 50-65 min p.i. CONCLUSIONS Both sensitivity modes provide comparable results for the full 65 min dynamic scans and abbreviated scans using the direct Patlak reconstruction method, with good Ki and DV estimates for 15 min short scans. For the indirect Patlak approach the UHS mode improved the Ki estimates for the abbreviated scans.
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Affiliation(s)
- W Lan
- Department of Nuclear Medicine and Clinical Molecular Imaging, University Hospital Tuebingen, Tuebingen, Germany
| | - H Sari
- Advanced Clinical Imaging Technology, Siemens Healthineers International AG, Lausanne, Switzerland
| | - A Rominger
- Department of Nuclear Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - C la Fougère
- Department of Nuclear Medicine and Clinical Molecular Imaging, University Hospital Tuebingen, Tuebingen, Germany
- Cluster of Excellence iFIT (EXC 2180) "Image Guided and Functionally Instructed Tumor Therapies", University of Tuebingen, Tuebingen, Germany
| | - F P Schmidt
- Department of Nuclear Medicine and Clinical Molecular Imaging, University Hospital Tuebingen, Tuebingen, Germany.
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, University of Tuebingen, Tuebingen, Germany.
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Feng X, Ran H, Liu H. Predicting time-of-flight with Cerenkov light in BGO: a three-stage network approach with multiple timing kernels prior. Phys Med Biol 2024; 69:175013. [PMID: 39137808 DOI: 10.1088/1361-6560/ad6ed8] [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: 04/17/2024] [Accepted: 08/13/2024] [Indexed: 08/15/2024]
Abstract
Objective.In the quest for enhanced image quality in positron emission tomography (PET) reconstruction, the introduction of time-of-flight (TOF) constraints in TOF-PET reconstruction offers superior signal-to-noise ratio. By employing BGO detectors capable of simultaneously emitting prompt Cerenkov light and scintillation light, this approach combines the high time resolution of prompt photons with the high energy resolution of scintillation light, thereby presenting a promising avenue for acquiring more precise TOF information.Approach.In Stage One, we train a raw method capable of predicting TOF information based on coincidence waveform pairs. In Stage Two, the data is categorized into 25 classes based on signal rise time, and the pre-trained raw method is utilized to obtain TOF kernels for each of the 25 classes, thereby generating prior knowledge. Within Stage Three, our proposed deep learning (DL) module, combined with a bias fine-tuning module, utilizes the kernel prior to provide bias compensation values for the data, thereby refining the first-stage outputs and obtaining more accurate TOF predictions.Main results.The three-stage network built upon the LED method resulted in improvements of 11.7 ps and 41.8 ps for full width at half maximum (FWHM) and full width at tenth maximum (FWTM), respectively. Optimal performance was achieved with FWHM of 128.2 ps and FWTM of 286.6 ps when CNN and Transformer were utilized in Stages One and Three, respectively. Further enhancements of 2.3 ps and 3.5 ps for FWHM and FWTM were attained through data augmentation methods.Significance.This study employs neural networks to compensate for the timing delays in mixed (Cerenkov and scintillation photons) signals, combining multiple timing kernels as prior knowledge with DL models. This integration yields optimal predictive performance, offering a superior solution for TOF-PET research utilizing Cerenkov signals.
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Affiliation(s)
- Xuhui Feng
- State Key Laboratory of Extreme Photonics and Instrumentation, College of Optical Science and Engineering, Zhejiang University, Hangzhou 310027, People's Republic of China
| | - Hengjia Ran
- State Key Laboratory of Extreme Photonics and Instrumentation, College of Optical Science and Engineering, Zhejiang University, Hangzhou 310027, People's Republic of China
| | - Huafeng Liu
- State Key Laboratory of Extreme Photonics and Instrumentation, College of Optical Science and Engineering, Zhejiang University, Hangzhou 310027, People's Republic of China
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Villa I, Monguzzi A, Lorenzi R, Orfano M, Babin V, Hájek F, Kuldová K, Kučerková R, Beitlerová A, Mattei I, Buresova H, Pjatkan R, Čuba V, Prouzová Procházková L, Nikl M. On the Origin of the Light Yield Enhancement in Polymeric Composite Scintillators Loaded with Dense Nanoparticles. NANO LETTERS 2024; 24:8248-8256. [PMID: 38949190 DOI: 10.1021/acs.nanolett.4c00681] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/02/2024]
Abstract
Fast emitting polymeric scintillators are requested in advanced applications where high speed detectors with a large signal-to-noise ratio are needed. However, their low density implies a weak stopping power of high energy radiation and thus a limited light output and sensitivity. To enhance their performance, polymeric scintillators can be loaded with dense nanoparticles (NPs). We investigate the properties of a series of polymeric scintillators by means of photoluminescence and scintillation spectroscopy, comparing standard scintillators with a composite system loaded with dense hafnium dioxide (HfO2) NPs. The nanocomposite shows a scintillation yield enhancement of +100% with an unchanged time response. We provide for the first time an interpretation of this effect, pointing out the local effect of NPs in the generation of emissive states upon interaction with ionizing radiation. The obtained results indicate that coupling fast conjugated emitters with optically inert dense NPs could lead to surpassing the actual limits of pure polymeric scintillators.
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Affiliation(s)
- Irene Villa
- Dipartimento di Scienza Dei Materiali, Università Degli Studi Milano-Bicocca, 20125 Milano, Italy
| | - Angelo Monguzzi
- Dipartimento di Scienza Dei Materiali, Università Degli Studi Milano-Bicocca, 20125 Milano, Italy
- NANOMIB, Center for Biomedical Nanomedicine, University of Milano-Bicocca, P.zza Ateneo Nuovo 1, 20126 Milan, Italy
| | - Roberto Lorenzi
- Dipartimento di Scienza Dei Materiali, Università Degli Studi Milano-Bicocca, 20125 Milano, Italy
| | - Matteo Orfano
- Dipartimento di Scienza Dei Materiali, Università Degli Studi Milano-Bicocca, 20125 Milano, Italy
| | - Vladimir Babin
- FZU-Institute of Physics of the Czech Academy of Sciences, Cukrovarnická 10/112, 16 200 Prague, Czech Republic
| | - František Hájek
- FZU-Institute of Physics of the Czech Academy of Sciences, Cukrovarnická 10/112, 16 200 Prague, Czech Republic
| | - Karla Kuldová
- FZU-Institute of Physics of the Czech Academy of Sciences, Cukrovarnická 10/112, 16 200 Prague, Czech Republic
| | - Romana Kučerková
- FZU-Institute of Physics of the Czech Academy of Sciences, Cukrovarnická 10/112, 16 200 Prague, Czech Republic
| | - Alena Beitlerová
- FZU-Institute of Physics of the Czech Academy of Sciences, Cukrovarnická 10/112, 16 200 Prague, Czech Republic
| | - Ilaria Mattei
- INFN Sezione di Milano, via G. Celoria 16, 20133 Milan, Italy
| | - Hana Buresova
- NUVIA a.s., Trojanova 117, 278 01 Kralupy nad Vltavou, Czech Republic
| | - Radek Pjatkan
- NUVIA a.s., Trojanova 117, 278 01 Kralupy nad Vltavou, Czech Republic
| | - Václav Čuba
- Faculty of Nuclear Sciences and Physical Engineering CTU in Prague, 115 19 Praha, Czech Republic
| | - Lenka Prouzová Procházková
- FZU-Institute of Physics of the Czech Academy of Sciences, Cukrovarnická 10/112, 16 200 Prague, Czech Republic
- Faculty of Nuclear Sciences and Physical Engineering CTU in Prague, 115 19 Praha, Czech Republic
| | - Martin Nikl
- FZU-Institute of Physics of the Czech Academy of Sciences, Cukrovarnická 10/112, 16 200 Prague, Czech Republic
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Zeng X, LaBella A, Wang Z, Li Y, Tan W, Goldan AH. Depth-encoding using optical photon TOF in a prism-PET detector with tapered crystals. Med Phys 2024; 51:4044-4055. [PMID: 38682574 DOI: 10.1002/mp.17095] [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: 01/05/2024] [Revised: 03/11/2024] [Accepted: 04/10/2024] [Indexed: 05/01/2024] Open
Abstract
BACKGROUND High-resolution brain positron emission tomography (PET) scanner is emerging as a significant and transformative non-invasive neuroimaging tool to advance neuroscience research as well as improve diagnosis and treatment in neurology and psychiatry. Time-of-flight (TOF) and depth-of-interaction (DOI) information provide markedly higher PET imaging performance by increasing image signal-to-noise ratio and mitigating spatial resolution degradation due to parallax error, respectively. PET detector modules that utilize light sharing can inherently carry DOI information from the multiple timestamps that are generated per gamma event. The difference between two timestamps that are triggered by scintillation photons traveling in opposite directions signifies the event's depth-dependent optical photon TOF (oTOF). However, light leak at the crystal-readout interface substantially degrades the resolution of this oTOF-based depth encoding. PURPOSE We demonstrate the feasibility of oTOF-based depth encoding by mitigating light leak in single-ended-readout Prism-PET detector modules using tapered crystals. Minimizing light leak also improved both energy-based DOI and coincidence timing resolutions. METHODS The tapered Prism-PET module consists of a 16 × $\times$ 16 array of 1.5 × $\times$ 1.5 × $\times$ 20 mm 3 ${\rm {mm}}^3$ lutetium yttrium oxyorthosillicate (LYSO) crystals, which are tapered down to 1.2 × $\times$ 1.2 mm 2 ${\rm {mm}}^2$ at the crystal-readout interface. The LYSO array couples 4-to-1 to an 8 × $\times$ 8 array of 3 × $\times$ 3 mm 2 ${\rm {mm}}^2$ silicon photomultiplier (SiPM) pixels on the tapered end and to a segmented prismatoid light guide array on the opposite end. Performance of tapered and non-tapered Prism-PET detectors was experimentally characterized and evaluated by measuring flood histogram, energy resolution, energy-, and oTOF-based DOI resolutions, and coincidence timing resolution. Sensitivities of scanners using different Prism-PET detector designs were simulated using Geant4 application for tomographic emission (GATE). RESULTS For the tapered (non-tapered) Prism-PET module, the measured full width at half maximum (FWHM) energy, timing, energy-based DOI, and oTOF-based DOI resolutions were 8.88 (11.18)%, 243 (286) ps, 2.35 (3.18) mm, and 5.42 (13.87) mm, respectively. The scanner sensitivities using non-tapered and tapered crystals, and 10 rings of detector modules, were simulated to be 30.9 and 29.5 kcps/MBq, respectively. CONCLUSIONS The tapered Prism-PET module with minimized light leak enabled the first experimental report of oTOF-based depth encoding at the detector module level. It also enabled the utilization of thinner (i.e., 0.1 mm) inter-crystal spacing with barium sulfate as the reflector while also improving energy-based DOI and timing resolutions.
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Affiliation(s)
- Xinjie Zeng
- Department of Radiology, Weill Cornell Medical College, Cornell University, New York, New York, USA
- Department of Electrical and Computer Engineering, College of Engineering and Applied Sciences, Stony Brook University, Stony Brook, New York, USA
| | - Andy LaBella
- Department of Radiology, Renaissance School of Medicine, Stony Brook University, Stony Brook, New York, USA
| | - Zipai Wang
- Department of Radiology, Weill Cornell Medical College, Cornell University, New York, New York, USA
- Department of Biomedical Engineering, College of Engineering and Applied Sciences, Stony Brook University, Stony Brook, New York, USA
| | - Yixin Li
- Department of Radiology, Weill Cornell Medical College, Cornell University, New York, New York, USA
- Department of Electrical and Computer Engineering, College of Engineering and Applied Sciences, Stony Brook University, Stony Brook, New York, USA
| | - Wanbin Tan
- Department of Radiology, Weill Cornell Medical College, Cornell University, New York, New York, USA
- Department of Biomedical Engineering, College of Engineering and Applied Sciences, Stony Brook University, Stony Brook, New York, USA
| | - Amir H Goldan
- Department of Radiology, Weill Cornell Medical College, Cornell University, New York, New York, USA
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Feng X, Muhashi A, Onishi Y, Ota R, Liu H. Transformer-CNN hybrid network for improving PET time of flight prediction. Phys Med Biol 2024; 69:115047. [PMID: 38749457 DOI: 10.1088/1361-6560/ad4c4d] [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: 01/09/2024] [Accepted: 05/15/2024] [Indexed: 05/31/2024]
Abstract
Objective.In positron emission tomography (PET) reconstruction, the integration of time-of-flight (TOF) information, known as TOF-PET, has been a major research focus. Compared to traditional reconstruction methods, the introduction of TOF enhances the signal-to-noise ratio of images. Precision in TOF is measured by full width at half maximum (FWHM) and the offset from ground truth, referred to as coincidence time resolution (CTR) and bias.Approach.This study proposes a network combining transformer and convolutional neural network (CNN) to utilize TOF information from detector waveforms, using event waveform pairs as inputs. This approach integrates the global self-attention mechanism of Transformer, which focuses on temporal relationships, with the local receptive field of CNN. The combination of global and local information allows the network to assign greater weight to the rising edges of waveforms, thereby extracting valuable temporal information for precise TOF predictions. Experiments were conducted using lutetium yttrium oxyorthosilicate (LYSO) scintillators and silicon photomultiplier (SiPM) detectors. The network was trained and tested using the waveform datasets after cropping.Main results.Compared to the constant fraction discriminator (CFD), CNN, CNN with attention, long short-term memory (LSTM) and Transformer, our network achieved an average CTR of 189 ps, reducing it by 82 ps (more than 30%), 13 ps (6.4%), 12 ps (6.0%), 16 ps (7.8%) and 9 ps (4.6%), respectively. Additionally, a reduction of 10.3, 8.7, 6.7 and 4 ps in average bias was achieved compared to CNN, CNN with attention, LSTM and Transformer.Significance.This work demonstrates the potential of applying the Transformer for PET TOF estimation using real experimental data. Through the integration of both CNN and Transformer with local and global attention, it achieves optimal performance, thereby presenting a novel direction for future research in this field.
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Affiliation(s)
- Xuhui Feng
- The State Key Laboratory of Modern Optical Instrumentation, College of Optical Science and Engineering, Zhejiang University, Hangzhou 310027, People's Republic of China
| | - Amanjule Muhashi
- The State Key Laboratory of Modern Optical Instrumentation, College of Optical Science and Engineering, Zhejiang University, Hangzhou 310027, People's Republic of China
| | - Yuya Onishi
- The Central Research Laboratory, Hamamatsu Photonics K.K., 5000 Hirakuchi, Hamakita-ku, Hamamatsu 434-8601, Japan
| | - Ryosuke Ota
- The Central Research Laboratory, Hamamatsu Photonics K.K., 5000 Hirakuchi, Hamakita-ku, Hamamatsu 434-8601, Japan
| | - Huafeng Liu
- The State Key Laboratory of Modern Optical Instrumentation, College of Optical Science and Engineering, Zhejiang University, Hangzhou 310027, People's Republic of China
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Smith RL, Bartley L, O'Callaghan C, Haberska L, Marshall C. NEMA NU 2-2018 evaluation and image quality optimization of a new generation digital 32-cm axial field-of-view Omni Legend PET-CT using a genetic evolutionary algorithm. Biomed Phys Eng Express 2024; 10:025032. [PMID: 38346328 DOI: 10.1088/2057-1976/ad286c] [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: 09/24/2023] [Accepted: 02/12/2024] [Indexed: 02/21/2024]
Abstract
A performance evaluation was conducted on the new General Electric (GE) digital Omni Legend PET-CT system with 32 cm extended field of view. The first commercially available clinical digital bismuth germanate system. The system does not use time of flight (ToF). Testing was performed in accordance with the NEMA NU2-2018 standard. A comparison was made between two other commercial GE scanners with extended fields of view; the Discovery MI - 6 ring (ToF enabled) and the Discovery IQ (non-ToF). A genetic evolutionary algorithm was developed to optimize image reconstruction parameters from image quality assessments. The Omni demonstrated average spatial resolutions at 1 cm radial offset as 3.9 mm FWHM. The total system sensitivity at the center was 44.36 cps/kBq. The peak NECR was measured as 501 kcps at 17.8 kBq ml-1with a 35.48% scatter fraction. The maximum count-rate error below NECR peak was 5.5%. Using standard iterative reconstructions, sphere contrast recovery coefficients were from 52.7 ± 3.2% (10 mm) to 92.5 ± 2.4% (37 mm). The PET-CT co-registration accuracy was 2.4 mm. In place of ToF, the Omni employs software corrections through a pre-trained neural network (PDL) (trained on non-ToF to ToF) that takes Bayesian penalized likelihood reconstruction (Q.Clear) images as input. The optimum parameters for image reconstruction, determined using the genetic algorithm were a Q.Clear parameter,β, of 350 and a 'medium' PDL setting. Using standard iterative reconstructions, the Omni initially showed increased background variability compared to the Discovery MI. With optimized PDL reconstruction parameters selected using the genetic algorithm the performance of the Omni surpassed that of the Discovery MI on all NEMA tests. The genetic algorithm's demonstrated ability to enhance image quality in PET-CT imaging underscores the importance of algorithm driven optimization and underscores the requirement to validate its use in the clinical setting.
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Affiliation(s)
- Rhodri Lyn Smith
- The Wales Research and Diagnostic Positron Emission Tomography Imaging Centre, Cardiff University, School of Medicine, Cardiff, CF14 4XN, Wales, United Kingdom
| | - Lee Bartley
- Radiology, Cardiff and Vale University Health Board, University Hospital of Wales, Cardiff, CF14 4XW, Wales, United Kingdom
| | - Christopher O'Callaghan
- Radiology, Cardiff and Vale University Health Board, University Hospital of Wales, Cardiff, CF14 4XW, Wales, United Kingdom
| | - Luiza Haberska
- The Wales Research and Diagnostic Positron Emission Tomography Imaging Centre, Cardiff University, School of Medicine, Cardiff, CF14 4XN, Wales, United Kingdom
| | - Chris Marshall
- The Wales Research and Diagnostic Positron Emission Tomography Imaging Centre, Cardiff University, School of Medicine, Cardiff, CF14 4XN, Wales, United Kingdom
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Jeong D, Tao L, Song XR, Adams Z, Zhang X, Wang J, Levin CS. Simulation of ionization charge carrier cascade time and density for a new radiation detection method based on modulation of optical properties. Med Phys 2024; 51:1383-1395. [PMID: 38064645 PMCID: PMC10922253 DOI: 10.1002/mp.16855] [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: 02/08/2023] [Revised: 10/25/2023] [Accepted: 10/26/2023] [Indexed: 02/10/2024] Open
Abstract
BACKGROUND In time-of-flight PET, image quality and accuracy can be enhanced by improving the annihilation photon pair coincidence time resolution, which is the variation in the arrival time difference between the two annihilation photons emitted from each positron decay in the patient. Recent studies suggest direct detection of ionization tracks and their resulting modulation of optical properties, instead of scintillation, can improve the CTR significantly, potentially down to less than 10 ps CTR. However, the arrival times of the 511 keV photons are not predictable, leading to challenges in the spatiotemporal localization characterization of the induced charge carriers in the detector crystal. PURPOSE To establish an optimized experimental setup for measuring ionization induced modulation of optical properties, it is critical to develop a versatile simulation algorithm that can handle multiple detector material properties and time-resolved charge carrier dynamics. METHODS We expanded our previous algorithm and simulated ionization tracks, cascade time and induced charge carrier density over time in different materials. For designing a proof-of-concept experiment, we simulated ultrafast electrons and free-electron x-ray photons for timing characterization along with alpha and beta particles for higher spatial localization. RESULTS With 3 MeV ultrafast electrons, by reducing detector crystal thickness, we can effectively reduce the ionization cascade time to 0.79 ps and deposited energy to 198.5 keV, which is on the order of the desired 511 keV energy. Alpha source simulations produced a cascade time of 2.45 ps and charge carrier density of 6.39 × 1020 cm-3 . Compared to the previous results obtained from 511 keV photon-induced ionization track simulations, the cascade time displayed similar characteristics, while the charge density was found to be higher. These findings suggest that alpha sources have the potential to generate a stronger ionization-induced signal using the modulation of optical properties as the detection mechanism. CONCLUSIONS This work provides a guideline to understand, design and optimize an experimental platform that is highly sensitive and temporally precise enough to detect single 511 keV photon interactions with a goal to advance CTR for ToF-PET.
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Affiliation(s)
- Diana Jeong
- Department of Radiology, Stanford University, Stanford, USA
| | - Li Tao
- Department of Radiology, Stanford University, Stanford, USA
- Department of Electrical Engineering, Stanford University, Stanford, USA
| | - Xin Ran Song
- Department of Radiology, Stanford University, Stanford, USA
| | - Zander Adams
- Department of Radiology, Stanford University, Stanford, USA
| | - Xin Zhang
- Department of Radiology, Stanford University, Stanford, USA
| | - Jinghui Wang
- Department of Radiation Oncology, Stanford University, Stanford, USA
| | - Craig S Levin
- Department of Radiology, Stanford University, Stanford, USA
- Department of Electrical Engineering, Stanford University, Stanford, USA
- Department of Physics, Stanford University, Stanford, USA
- Department of Bioengineering, Stanford University, Stanford, USA
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9
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Taha A, Alassi A, Gjedde A, Wong DF. Transforming Neurology and Psychiatry: Organ-specific PET Instrumentation and Clinical Applications. PET Clin 2024; 19:95-103. [PMID: 37813719 DOI: 10.1016/j.cpet.2023.06.002] [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] [Indexed: 10/11/2023]
Abstract
PET technology has immense potential for furthering understanding of the brain and associated disorders, including advancements in high-resolution tomographs and hybrid imaging modalities. Novel radiotracers targeting specific neurotransmitter systems and molecular markers provide opportunities to unveil intricate mechanisms underlying neurologic and psychiatric conditions. As PET imaging techniques and analysis methods continue to be refined, the field is poised to make significant contributions to personalized medicine for more targeted and effective interventions. PET instrumentation has advanced the fields of neurology and psychiatry, providing insights into pathophysiology and development of effective treatments.
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Affiliation(s)
- Ahmed Taha
- Mallinckrodt Institute of Radiology, Washington University in St Louis, Saint Louis, MO, USA
| | - Amer Alassi
- Mallinckrodt Institute of Radiology, Washington University in St Louis, Saint Louis, MO, USA
| | - Albert Gjedde
- Department of Clinical Medicine, Translational Neuropsychiatry Unit, Aarhus University, Denmark; Department of Neuroscience, University of Copenhagen, Denmark
| | - Dean F Wong
- Mallinckrodt Institute of Radiology, Departments of Radiology, Psychiatry, Neurology, Neuroscience, Washington University in St Louis, Saint Louis, MO, USA.
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10
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Nadig V, Hornisch M, Oehm J, Herweg K, Schulz V, Gundacker S. 16-channel SiPM high-frequency readout with time-over-threshold discrimination for ultrafast time-of-flight applications. EJNMMI Phys 2023; 10:76. [PMID: 38044383 PMCID: PMC10694125 DOI: 10.1186/s40658-023-00594-z] [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] [Received: 09/01/2023] [Accepted: 11/20/2023] [Indexed: 12/05/2023] Open
Abstract
BACKGROUND Over the past five years, ultrafast high-frequency (HF) readout concepts have advanced the timing performance of silicon photomultipliers (SiPMs). The shown impact in time-of-flight (TOF) techniques can further push the limits in light detection and ranging (LiDAR), time-of-flight positron-emission tomography (TOF-PET), time-of-flight computed tomography (TOF-CT) or high-energy physics (HEP). However, upscaling these electronics to a system-applicable, multi-channel readout, has remained a challenging task, posed by the use of discrete components and a high power consumption. To this day, there are no means to exploit the high TOF resolution of these electronics on system scale or to measure the actual timing performance limits of a full detector block. METHODS In this work, we present a 16-channel HF readout board, including leading-edge discrimination and a linearized time-over-threshold (TOT) method, which is fully compatible with a high-precision time-to-digital converters (TDCs), such as the picoTDC developed at CERN. The discrete implementation allows ideal adaptation of this readout to a broad range of detection tasks. As a first step, the functionality of the circuit has been tested using the TOFPET2 ASIC as back-end electronics to emulate the TDC, also in view of its properties as a highly scalable data acquisition solution. RESULTS The produced board is able to mitigate influences of baseline shifts in the TOFPET2 front end, which has been shown in experiments with a pulsed laser, increasing the achievable intrinsic coincidence timing resolution (CTR) of the TOFPET2 readout electronics from 70 ps (FWHM) to 62 ps (FWHM). Single-channel coincidence experiments including a [Formula: see text]-source, 2[Formula: see text]2[Formula: see text]3 mm[Formula: see text] LYSO:Ce,Ca crystals and Broadcom NUV-MT SiPMs resulted in a CTR of 118 ps (FWHM). For a 4[Formula: see text]4 matrix of 3.88[Formula: see text]3.88[Formula: see text]19 mm[Formula: see text] LYSO:Ce,Ca crystals one-to-one coupled to a 4[Formula: see text]4 array of Broadcom NUV-MT SiPMs, an average CTR of 223 ps (FWHM) was obtained. CONCLUSION The implemented 16-channel HF electronics are fully functionall and have a negligible influence on the timing performance of the back-end electronics used, here the TOFPET2 ASIC. The ongoing integration of the picoTDC with the 16-channel HF board is expected to further set the path toward sub-100 ps TOF-PET and sub-30ps TOF resolution for single-photon detection.
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Affiliation(s)
- Vanessa Nadig
- Department of Physics of Molecular Imaging Systems, Experimental Molecular Imaging, RWTH Aachen University, Forckenbeckstraße 55, 52074, Aachen, Germany
| | - Matthias Hornisch
- Department of Physics of Molecular Imaging Systems, Experimental Molecular Imaging, RWTH Aachen University, Forckenbeckstraße 55, 52074, Aachen, Germany
| | - Jakob Oehm
- Department of Physics of Molecular Imaging Systems, Experimental Molecular Imaging, RWTH Aachen University, Forckenbeckstraße 55, 52074, Aachen, Germany
| | - Katrin Herweg
- Department of Physics of Molecular Imaging Systems, Experimental Molecular Imaging, RWTH Aachen University, Forckenbeckstraße 55, 52074, Aachen, Germany
| | - Volkmar Schulz
- Department of Physics of Molecular Imaging Systems, Experimental Molecular Imaging, RWTH Aachen University, Forckenbeckstraße 55, 52074, Aachen, Germany
- Hyperion Hybrid Imaging Systems GmbH, Pauwelsstraße 19, 52074, Aachen, Germany
- III. Physikalisches Institut B, RWTH Aachen University, Otto-Blumenthal-Straße, 52074, Aachen, Germany
- Fraunhofer Institute for Digital Medicine MEVIS, Forckenbeckstraße 55, 52074, Aachen, Germany
| | - Stefan Gundacker
- Department of Physics of Molecular Imaging Systems, Experimental Molecular Imaging, RWTH Aachen University, Forckenbeckstraße 55, 52074, Aachen, Germany.
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Kersting D, Moraitis A, Sraieb M, Zarrad F, Umutlu L, Rischpler C, Fendler WP, Herrmann K, Weber M, Conti M, Fragoso Costa P, Jentzen W. Quantification performance of silicon photomultiplier-based PET for small 18F-, 68Ga- and 124I-avid lesions in the context of radionuclide therapy planning. Phys Med 2023; 114:103149. [PMID: 37778973 DOI: 10.1016/j.ejmp.2023.103149] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 09/03/2023] [Accepted: 09/22/2023] [Indexed: 10/03/2023] Open
Abstract
PURPOSE The aim of this study was to investigate conditions for reliable quantification of sub-centimeter lesions with low18F,68Ga, and124I uptake using a silicon photomultiplier-based PET/CT system. METHODS A small tumor phantom was investigated under challenging but clinically realistic conditions resembling prostate and thyroid cancer lymph node metastases (6 spheres with 3.7-9.7 mm in diameter, 9 different activity concentrations ranging from about 0.25-25 kBq/mL, and a signal-to-background ratio of 20). Radionuclides with different positron branching ratios and prompt gamma coincidence contributions were investigated. Maximum-, contour-, and oversize-based partial volume effect (PVE) correction approaches were applied. Detection and quantification performance were estimated, considering a ±30 % deviation between imaged-derived and true activity concentrations as acceptable. A standard and a prolonged acquisition time and two image reconstruction algorithms (time-of-flight with/without point spread function modelling) were analyzed. Clinical data were evaluated to assess agreement of PVE-correction approaches indicating lesion quantification validity. RESULTS The smallest 3.7-mm sphere was not visible. If the lesions were clearly observed, quantification was, except for a few cases, acceptable using contour- or oversized-based PVE-corrections. Quantification accuracy did not substantially differ between 18F, 68Ga, and 124I. No systematic differences between the analyzed reconstruction algorithms or shorter and larger acquisition times were observed. In the clinical evaluation of 20 lesions, an excellent statistical agreement between oversize- and contour-based PVE-corrections was observed. CONCLUSIONS At the lower end of size (<10 mm) and activity concentration ranges of lymph-node metastases, quantification with reasonable accuracy is possible for 18F, 68Ga, and 124I, possibly allowing pre-therapeutic lesion dosimetry and individualized radionuclide therapy planning.
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Affiliation(s)
- David Kersting
- Department of Nuclear Medicine, West German Cancer Center (WTZ), University Hospital Essen, University of Duisburg-Essen, Essen, Germany; German Cancer Consortium (DKTK), Partner Site University Hospital Essen, Essen, Germany.
| | - Alexandros Moraitis
- Department of Nuclear Medicine, West German Cancer Center (WTZ), University Hospital Essen, University of Duisburg-Essen, Essen, Germany; German Cancer Consortium (DKTK), Partner Site University Hospital Essen, Essen, Germany
| | - Miriam Sraieb
- Department of Nuclear Medicine, West German Cancer Center (WTZ), University Hospital Essen, University of Duisburg-Essen, Essen, Germany; German Cancer Consortium (DKTK), Partner Site University Hospital Essen, Essen, Germany
| | - Fadi Zarrad
- Department of Nuclear Medicine, West German Cancer Center (WTZ), University Hospital Essen, University of Duisburg-Essen, Essen, Germany; German Cancer Consortium (DKTK), Partner Site University Hospital Essen, Essen, Germany
| | - Lale Umutlu
- German Cancer Consortium (DKTK), Partner Site University Hospital Essen, Essen, Germany; Institute of Diagnostic and Interventional Radiology and Neuroradiology, West German Cancer Center (WTZ), University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Christoph Rischpler
- Department of Nuclear Medicine, West German Cancer Center (WTZ), University Hospital Essen, University of Duisburg-Essen, Essen, Germany; German Cancer Consortium (DKTK), Partner Site University Hospital Essen, Essen, Germany
| | - Wolfgang Peter Fendler
- Department of Nuclear Medicine, West German Cancer Center (WTZ), University Hospital Essen, University of Duisburg-Essen, Essen, Germany; German Cancer Consortium (DKTK), Partner Site University Hospital Essen, Essen, Germany
| | - Ken Herrmann
- Department of Nuclear Medicine, West German Cancer Center (WTZ), University Hospital Essen, University of Duisburg-Essen, Essen, Germany; German Cancer Consortium (DKTK), Partner Site University Hospital Essen, Essen, Germany
| | - Manuel Weber
- Department of Nuclear Medicine, West German Cancer Center (WTZ), University Hospital Essen, University of Duisburg-Essen, Essen, Germany; German Cancer Consortium (DKTK), Partner Site University Hospital Essen, Essen, Germany
| | | | - Pedro Fragoso Costa
- Department of Nuclear Medicine, West German Cancer Center (WTZ), University Hospital Essen, University of Duisburg-Essen, Essen, Germany; German Cancer Consortium (DKTK), Partner Site University Hospital Essen, Essen, Germany
| | - Walter Jentzen
- Department of Nuclear Medicine, West German Cancer Center (WTZ), University Hospital Essen, University of Duisburg-Essen, Essen, Germany; German Cancer Consortium (DKTK), Partner Site University Hospital Essen, Essen, Germany
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Xin Z, Kao CM, Liu Y, Chen X, Zhang L, Wu P, Xie Q. The value of using heterogeneous detector groups for the development of time-of-flight (TOF) positron emission tomography (PET) systems. Biomed Phys Eng Express 2023; 9:055028. [PMID: 37567155 DOI: 10.1088/2057-1976/acef24] [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: 05/05/2023] [Accepted: 08/11/2023] [Indexed: 08/13/2023]
Abstract
Objective. Much recent attention on positron emission tomography (PET) is the development of time-of-flight (TOF) systems with ever-improving coincidence time resolution (CTR). This is because, when all other factors remain the same, a better CTR leads to images of better statistics and effectively increases the sensitivity of the system. However, detector designs that aggressively improve the CTR often compromise the detection efficiency (DE) and offset the benefit gained. Under this circumstance, in developing a TOF PET system it may be beneficial to employ heterogeneous detector groups to balance the overall CTR and DE of the system. In this study, we examine the potential value of this system design strategy by considering two-dimensional systems that assume several representative ways of mixing two detector groups.Approach. The study is based on computer simulation and specifically considers medium time-resolution (MTR) detectors that have a 528 ps CTR and high time-resolution (HTR) detectors that have a 100 ps CTR and a DE that is 0.7 times that of the MTR detector. We examine contrast recovery, noise, and subjective quality of the resulting images under various ways of mixing the MTR and HTR detectors.Main results. With respect to the traditional configuration that adopts only the HTR detectors, symmetric heterogeneous configurations may offer comparable or better images while using considerably fewer HTRs. On the other hand, asymmetric heterogeneous configurations may allow the use of only a few HTRs for improving image quality locally.Significance. This study demonstrates the value of the proposed system-level design strategy of using heterogeneous detector groups for achieving high effective system sensitivity by factoring into the tradeoff between the CTR and DE of the detector.
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Affiliation(s)
- Zhiqiang Xin
- Department of Electronic Engineering and Information Science, University of Science and Technology of China, Hefei 230022, People's Republic of China
| | - Chien-Min Kao
- Department of Radiology, The University of Chicago, 5841 S. Maryland Avenue, Chicago, Illinois 60637, United States of America
| | - Yuqing Liu
- Institute of Artificial Intelligence, Hefei Comprehensive National Science Center, Hefei 230094, People's Republic of China
| | - Xun Chen
- Department of Electronic Engineering and Information Science, University of Science and Technology of China, Hefei 230022, People's Republic of China
| | - Labao Zhang
- Research Institute of Superconductor Electronics, School of Electronic Science and Engineering, Nanjing University, Nanjing 210093, People's Republic of China
| | - Peiheng Wu
- Research Institute of Superconductor Electronics, School of Electronic Science and Engineering, Nanjing University, Nanjing 210093, People's Republic of China
| | - Qingguo Xie
- Department of Electronic Engineering and Information Science, University of Science and Technology of China, Hefei 230022, People's Republic of China
- Institute of Artificial Intelligence, Hefei Comprehensive National Science Center, Hefei 230094, People's Republic of China
- Wuhan National Laboratory for Optoelectronics, Wuhan 430074, People's Republic of China
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Neumann KD, Broshek DK, Newman BT, Druzgal TJ, Kundu BK, Resch JE. Concussion: Beyond the Cascade. Cells 2023; 12:2128. [PMID: 37681861 PMCID: PMC10487087 DOI: 10.3390/cells12172128] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2023] [Revised: 08/14/2023] [Accepted: 08/17/2023] [Indexed: 09/09/2023] Open
Abstract
Sport concussion affects millions of athletes each year at all levels of sport. Increasing evidence demonstrates clinical and physiological recovery are becoming more divergent definitions, as evidenced by several studies examining blood-based biomarkers of inflammation and imaging studies of the central nervous system (CNS). Recent studies have shown elevated microglial activation in the CNS in active and retired American football players, as well as in active collegiate athletes who were diagnosed with a concussion and returned to sport. These data are supportive of discordance in clinical symptomology and the inflammatory response in the CNS upon symptom resolution. In this review, we will summarize recent advances in the understanding of the inflammatory response associated with sport concussion and broader mild traumatic brain injury, as well as provide an outlook for important research questions to better align clinical and physiological recovery.
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Affiliation(s)
- Kiel D. Neumann
- Department of Diagnostic Imaging, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA;
| | - Donna K. Broshek
- Department of Psychiatry and Neurobehavioral Sciences, University of Virginia, Charlottesville, VA 22903, USA;
| | - Benjamin T. Newman
- Department of Radiology and Medical Imaging, University of Virginia, Charlottesville, VA 22903, USA; (B.T.N.); (T.J.D.); (B.K.K.)
| | - T. Jason Druzgal
- Department of Radiology and Medical Imaging, University of Virginia, Charlottesville, VA 22903, USA; (B.T.N.); (T.J.D.); (B.K.K.)
| | - Bijoy K. Kundu
- Department of Radiology and Medical Imaging, University of Virginia, Charlottesville, VA 22903, USA; (B.T.N.); (T.J.D.); (B.K.K.)
| | - Jacob E. Resch
- Department of Kinesiology, University of Virginia, Charlottesville, VA 22903, USA
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14
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Gundacker S, Borghi G, Cherry SR, Gola A, Lee D, Merzi S, Penna M, Schulz V, Kwon SI. On timing-optimized SiPMs for Cherenkov detection to boost low cost time-of-flight PET. Phys Med Biol 2023; 68:165016. [PMID: 37467766 PMCID: PMC10410404 DOI: 10.1088/1361-6560/ace8ee] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 07/10/2023] [Accepted: 07/19/2023] [Indexed: 07/21/2023]
Abstract
Objective.Recent SiPM developments and improved front-end electronics have opened new doors in TOF-PET with a focus on prompt photon detection. For instance, the relatively high Cherenkov yield of bismuth-germanate (BGO) upon 511 keV gamma interaction has triggered a lot of interest, especially for its use in total body positron emission tomography (PET) scanners due to the crystal's relatively low material and production costs. However, the electronic readout and timing optimization of the SiPMs still poses many questions. Lab experiments have shown the prospect of Cherenkov detection, with coincidence time resolutions (CTRs) of 200 ps FWHM achieved with small pixels, but lack system integration due to an unacceptable high power uptake of the used amplifiers.Approach.Following recent studies the most practical circuits with lower power uptake (<30 mW) have been implemented and the CTR performance with BGO of newly developed SiPMs from Fondazione Bruno Kessler tested. These novel SiPMs are optimized for highest single photon time resolution (SPTR).Main results.We achieved a best CTR FWHM of 123 ps for 2 × 2 × 3 mm3and 243 ps for 3 × 3 × 20 mm3BGO crystals. We further show that with these devices a CTR of 106 ps is possible using commercially available 3 × 3 × 20 mm3LYSO:Ce,Mg crystals. To give an insight in the timing properties of these SiPMs, we measured the SPTR with black coated PbF2of 2 × 2 × 3 mm3size. We confirmed an SPTR of 68 ps FWHM published in literature for standard devices and show that the optimized SiPMs can improve this value to 42 ps. Pushing the SiPM bias and using 1 × 1 mm2area devices we measured an SPTR of 28 ps FWHM.Significance.We have shown that advancements in readout electronics and SiPMs can lead to improved CTR with Cherenkov emitting crystals. Enabling time-of-flight with BGO will trigger a high interest for its use in low-cost and total-body PET scanners. Furthermore, owing to the prompt nature of Cherenkov emission, future CTR improvements are conceivable, for which a low-power electronic implementation is indispensable. In an extended discussion we will give a roadmap to best timing with prompt photons.
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Affiliation(s)
- Stefan Gundacker
- Department of Physics of Molecular Imaging Systems, Institute for Experimental Molecular Imaging, RWTH Aachen University, Forckenbeckstrae 55, D-52074 Aachen, Germany
| | - Giacomo Borghi
- Fondazione Bruno Kessler, via Sommarive 18, Trento I-38123, Italy
| | - Simon R Cherry
- Department of Biomedical Engineering, University of California, Davis, One Shields Avenue, Davis, CA 95616, United States of America
| | - Alberto Gola
- Fondazione Bruno Kessler, via Sommarive 18, Trento I-38123, Italy
| | - Daehee Lee
- Department of Biomedical Engineering, University of California, Davis, One Shields Avenue, Davis, CA 95616, United States of America
| | - Stefano Merzi
- Fondazione Bruno Kessler, via Sommarive 18, Trento I-38123, Italy
| | - Michele Penna
- Fondazione Bruno Kessler, via Sommarive 18, Trento I-38123, Italy
- Dipartimento di Elettronica e Telecomunicazioni, Politecnico di Torino, Corso Duca degli Abruzzi 24, I-10129 Torino, Italy
| | - Volkmar Schulz
- Department of Physics of Molecular Imaging Systems, Institute for Experimental Molecular Imaging, RWTH Aachen University, Forckenbeckstrae 55, D-52074 Aachen, Germany
| | - Sun Il Kwon
- Department of Biomedical Engineering, University of California, Davis, One Shields Avenue, Davis, CA 95616, United States of America
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Weyts K, Quak E, Licaj I, Ciappuccini R, Lasnon C, Corroyer-Dulmont A, Foucras G, Bardet S, Jaudet C. Deep Learning Denoising Improves and Homogenizes Patient [ 18F]FDG PET Image Quality in Digital PET/CT. Diagnostics (Basel) 2023; 13:diagnostics13091626. [PMID: 37175017 PMCID: PMC10177812 DOI: 10.3390/diagnostics13091626] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 04/18/2023] [Accepted: 04/23/2023] [Indexed: 05/15/2023] Open
Abstract
Given the constant pressure to increase patient throughput while respecting radiation protection, global body PET image quality (IQ) is not satisfactory in all patients. We first studied the association between IQ and other variables, in particular body habitus, on a digital PET/CT. Second, to improve and homogenize IQ, we evaluated a deep learning PET denoising solution (Subtle PETTM) using convolutional neural networks. We analysed retrospectively in 113 patients visual IQ (by a 5-point Likert score in two readers) and semi-quantitative IQ (by the coefficient of variation in the liver, CVliv) as well as lesion detection and quantification in native and denoised PET. In native PET, visual and semi-quantitative IQ were lower in patients with larger body habitus (p < 0.0001 for both) and in men vs. women (p ≤ 0.03 for CVliv). After PET denoising, visual IQ scores increased and became more homogeneous between patients (4.8 ± 0.3 in denoised vs. 3.6 ± 0.6 in native PET; p < 0.0001). CVliv were lower in denoised PET than in native PET, 6.9 ± 0.9% vs. 12.2 ± 1.6%; p < 0.0001. The slope calculated by linear regression of CVliv according to weight was significantly lower in denoised than in native PET (p = 0.0002), demonstrating more uniform CVliv. Lesion concordance rate between both PET series was 369/371 (99.5%), with two lesions exclusively detected in native PET. SUVmax and SUVpeak of up to the five most intense native PET lesions per patient were lower in denoised PET (p < 0.001), with an average relative bias of -7.7% and -2.8%, respectively. DL-based PET denoising by Subtle PETTM allowed [18F]FDG PET global image quality to be improved and homogenized, while maintaining satisfactory lesion detection and quantification. DL-based denoising may render body habitus adaptive PET protocols unnecessary, and pave the way for the improvement and homogenization of PET modalities.
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Affiliation(s)
- Kathleen Weyts
- Department of Nuclear Medicine, Baclesse Cancer Centre, 14076 Caen, France
| | - Elske Quak
- Department of Nuclear Medicine, Baclesse Cancer Centre, 14076 Caen, France
| | - Idlir Licaj
- Department of Biostatistics, Baclesse Cancer Centre, 14076 Caen, France
- Department of Community Medicine, Faculty of Health Sciences, UiT The Arctic University of Norway, 9019 Tromsø, Norway
| | - Renaud Ciappuccini
- Department of Nuclear Medicine, Baclesse Cancer Centre, 14076 Caen, France
| | - Charline Lasnon
- Department of Nuclear Medicine, Baclesse Cancer Centre, 14076 Caen, France
| | - Aurélien Corroyer-Dulmont
- Department of Medical Physics, Baclesse Cancer Centre, 14076 Caen, France
- ISTCT Unit, CNRS, UNICAEN, Normandy University, GIP CYCERON, 14074 Caen, France
| | - Gauthier Foucras
- Department of Nuclear Medicine, Baclesse Cancer Centre, 14076 Caen, France
| | - Stéphane Bardet
- Department of Nuclear Medicine, Baclesse Cancer Centre, 14076 Caen, France
| | - Cyril Jaudet
- Department of Nuclear Medicine, Baclesse Cancer Centre, 14076 Caen, France
- Department of Medical Physics, Baclesse Cancer Centre, 14076 Caen, France
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Fragoso Costa P, Jentzen W, SÜßELBECK F, Fendler WP, Rischpler C, Herrmann K, Conti M, Kersting D, Weber M. Reduction of emission time for [68Ga]Ga-PSMA PET/CT using the digital biograph vision: a phantom study. THE QUARTERLY JOURNAL OF NUCLEAR MEDICINE AND MOLECULAR IMAGING : OFFICIAL PUBLICATION OF THE ITALIAN ASSOCIATION OF NUCLEAR MEDICINE (AIMN) [AND] THE INTERNATIONAL ASSOCIATION OF RADIOPHARMACOLOGY (IAR), [AND] SECTION OF THE SOCIETY OF... 2023; 67:57-68. [PMID: 34309334 DOI: 10.23736/s1824-4785.21.03300-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND The aim of this phantom study was to optimize the [68Ga]Ga-PSMA PET/CT examination in terms of scan time duration and image reconstruction parameters, in combination with PSF and TOF modelling, in a digital Biograph Vision PET/CT scanner. METHODS Three types of phantoms were used: 1) soft-tissue tumor phantom consisting of six spheres mounted in a torso phantom; 2) bone-lung tumor phantom; 3) resolution phantom. Phantom inserts were filled with activity concentrations (ACs) that were derived from clinical data. Phantom data were acquired in list-mode at one bed position. Images with emission data ranging from 30 to 210 s in 30-s increments were reconstructed from a reference image acquired with 3.5-min emission. Iterative image reconstruction (OSEM), point-spread-function (PSF) and time-of-flight (TOF) options were applied using different iterations, Gaussian filters, and voxel sizes. The criteria for image quality was lesion detectability and lesion quantification, evaluated as contrast-to-noise ratio (CNR) and maximum AC (peak AC), respectively. A threshold value of CNR above 6 and percentage maximum AC (peak AC) deviation range of ±20% of the reference image were considered acceptable. The proposed single-bed scan time reduction was projected to a whole-body examination (patient validation scan) using the continuous-bed-motion mode. RESULTS Sphere and background ACs of 20 kBq/mL and 1 kBq/mL were selected, respectively. The optimized single-bed scan time was approximately 60 s using OSEM-TOF or OSEM-TOF+PSF (four iterations, 4.0-mm Gaussian filter and almost isotropic voxel size of 3.0-mm side length), resulting in a PET spatial resolution of 6.3 mm for OSEM-TOF and 5.5 mm for OSEM-TOF+PSF. In the patient validation, the maximum percentage difference in lesion quantification between standard and optimized protocol (whole-body scan time of 15 vs. 5 min) was below 19%. CONCLUSIONS A reduction of single-bed and whole-body scan time for [68Ga]Ga-PSMA PET/CT compared to current recommended clinical acquisition protocols is postulated. Clinical studies are warranted to validate the applicability of this protocol.
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Affiliation(s)
- Pedro Fragoso Costa
- Department of Nuclear Medicine, Essen University Hospital, Duisburg-Essen University, Essen, Germany -
| | - Walter Jentzen
- Department of Nuclear Medicine, Essen University Hospital, Duisburg-Essen University, Essen, Germany
| | - Finja SÜßELBECK
- Department of Nuclear Medicine, Essen University Hospital, Duisburg-Essen University, Essen, Germany
| | - Wolfgang P Fendler
- Department of Nuclear Medicine, Essen University Hospital, Duisburg-Essen University, Essen, Germany
| | - Christoph Rischpler
- Department of Nuclear Medicine, Essen University Hospital, Duisburg-Essen University, Essen, Germany
| | - Ken Herrmann
- Department of Nuclear Medicine, Essen University Hospital, Duisburg-Essen University, Essen, Germany
| | | | - David Kersting
- Department of Nuclear Medicine, Essen University Hospital, Duisburg-Essen University, Essen, Germany
| | - Manuel Weber
- Department of Nuclear Medicine, Essen University Hospital, Duisburg-Essen University, Essen, Germany
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Naunheim S, Kuhl Y, Solf T, Schug D, Schulz V, Mueller F. Analysis of a convex time skew calibration for light sharing-based PET detectors. Phys Med Biol 2023; 68. [PMID: 36595338 DOI: 10.1088/1361-6560/aca872] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 12/01/2022] [Indexed: 12/05/2022]
Abstract
Objective.Positron emission tomography (PET) detectors providing attractive coincidence time resolutions (CTRs) offer time-of-flight information, resulting in an improved signal-to-noise ratio of the PET image. In applications with photosensor arrays that employ timestampers for individual channels, timestamps typically are not time synchronized, introducing time skews due to different signal pathways. The scintillator topology and transportation of the scintillation light might provoke further skews. If not accounted for these effects, the achievable CTR deteriorates. We studied a convex timing calibration based on a matrix equation. In this work, we extended the calibration concept to arbitrary structures targeting different aspects of the time skews and focusing on optimizing the CTR performance for detector characterization. The radiation source distribution, the stability of the estimations, and the energy dependence of calibration data are subject to the analysis.Approach.A coincidence setup, equipped with a semi-monolithic detector comprising 8 LYSO slabs, each 3.9 mm × 31.9 mm × 19.0 mm, and a one-to-one coupled detector with 8 × 8 LYSO segments of 3.9 mm × 3.9 mm × 19.0 mm volume is used. Both scintillators utilize a dSiPM (DPC3200-22-44, Philips Digital Photon Counting) operated in first photon trigger. The calibration was also conducted with solely one-to-one coupled detectors and extrapolated for a slab-only setup.Main results.All analyzed hyperparameters show a strong influence on the calibration. Using multiple radiation positions improved the skew estimation. The statistical significance of the calibration dataset and the utilized energy window was of great importance. Compared to a one-to-one coupled detector pair achieving CTRs of 224 ps the slab detector configuration reached CTRs down to 222 ps, demonstrating that slabs can compete with a clinically used segmented detector design.Significance.This is the first work that systematically studies the influence of hyperparameters on skew estimation and proposes an extension to arbitrary calibration structures (e.g. scintillator volumes) of a known calibration technique.
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Affiliation(s)
- Stephan Naunheim
- Department of Physics of Molecular Imaging Systems (PMI), Institute for Experimental Imaging, RWTH Aachen University, Germany
| | - Yannick Kuhl
- Department of Physics of Molecular Imaging Systems (PMI), Institute for Experimental Imaging, RWTH Aachen University, Germany
| | - Torsten Solf
- Philips Digital Photon Counting, Aachen, Germany
| | - David Schug
- Department of Physics of Molecular Imaging Systems (PMI), Institute for Experimental Imaging, RWTH Aachen University, Germany.,Hyperion Hybrid Imaging Systems GmbH, Aachen, Germany
| | - Volkmar Schulz
- Department of Physics of Molecular Imaging Systems (PMI), Institute for Experimental Imaging, RWTH Aachen University, Germany.,Hyperion Hybrid Imaging Systems GmbH, Aachen, Germany.,Fraunhofer Institute for Digital Medicine MEVIS, Aachen, Germany.,Physics Institute III B, RWTH Aachen University, Aachen, Germany
| | - Florian Mueller
- Department of Physics of Molecular Imaging Systems (PMI), Institute for Experimental Imaging, RWTH Aachen University, Germany
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18
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Mohr P, Efthimiou N, Pagano F, Kratochwil N, Pizzichemi M, Tsoumpas C, Auffray E, Ziemons K. Image Reconstruction Analysis for Positron Emission Tomography With Heterostructured Scintillators. IEEE TRANSACTIONS ON RADIATION AND PLASMA MEDICAL SCIENCES 2023; 7:41-51. [PMID: 37397180 PMCID: PMC10312993 DOI: 10.1109/trpms.2022.3208615] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/15/2023]
Abstract
The concept of structure engineering has been proposed for exploring the next generation of radiation detectors with improved performance. A TOF-PET geometry with heterostructured scintillators with a pixel size of 3.0 × 3.1 × 15 mm3 was simulated using Monte Carlo. The heterostructures consisted of alternating layers of BGO as a dense material with high stopping power and plastic (EJ232) as a fast light emitter. The detector time resolution was calculated as a function of the deposited and shared energy in both materials on an event-by-event basis. While sensitivity was reduced to 32% for 100-μm thick plastic layers and 52% for 50 μm, the coincidence time resolution (CTR) distribution improved to 204 ± 49 and 220 ± 41 ps, respectively, compared to 276 ps that we considered for bulk BGO. The complex distribution of timing resolutions was accounted for in the reconstruction. We divided the events into three groups based on their CTR and modeled them with different Gaussian TOF kernels. On an NEMA IQ phantom, the heterostructures had better contrast recovery in early iterations. On the other hand, BGO achieved a better contrast-to-noise ratio (CNR) after the 15th iteration due to the higher sensitivity. The developed simulation and reconstruction methods constitute new tools for evaluating different detector designs with complex time responses.
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Affiliation(s)
- Philipp Mohr
- Factuly of Chemistry and Biotechnology, FH Aachen University of Applied Sciences, 52428 Jülich, Germany, and also with the Experimental Physics Department, European Organization for Nuclear Research (CERN), 1201 Geneva, Switzerland. He is now with the Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, 9713 GZ Groningen, The Netherlands
| | - Nikos Efthimiou
- Department Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104 USA
| | - Fiammetta Pagano
- Physics Department, University of Milano-Bicocca, 20126 Milan, Italy, and also with the Experimental Physics Department, European Organization for Nuclear Research (CERN), 1201 Geneva, Switzerland
| | - Nicolaus Kratochwil
- Experimental Physics Department, European Organization for Nuclear Research (CERN), 1211 Geneva, Switzerland
| | - Marco Pizzichemi
- Physics Department, University of Milano-Bicocca, 20126 Milan, Italy, and also with the Experimental Physics Department, European Organization for Nuclear Research (CERN), 1201 Geneva, Switzerland
| | - Charalampos Tsoumpas
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, 9713 GZ Groningen, The Netherlands, and also with the Biomedical Imaging Science Department, Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, LS2 9JT Leeds, U.K
| | - Etiennette Auffray
- Experimental Physics Department, European Organization for Nuclear Research (CERN), 1211 Geneva, Switzerland
| | - Karl Ziemons
- Faculty of Biomedical Engineering and Technomathematics, FH Aachen University of Applied Sciences, 52428 Jülich, Germany
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19
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A new brain dedicated PET scanner with 4D detector information. BIO-ALGORITHMS AND MED-SYSTEMS 2022. [DOI: 10.2478/bioal-2022-0083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Abstract
In this article, we present the geometrical design and preliminary results of a high sensitivity organ-specific Positron Emission Tomography (PET) system dedicated to the study of the human brain. The system, called 4D-PET, will allow accurate imaging of brain studies due to its expected high sensitivity, high 3D spatial resolution and, by including precise photon time of flight (TOF) information, a boosted signal-to-noise ratio (SNR).
The 4D-PET system incorporates an innovative detector design based on crystal slabs (semi-monolithic) that enables accurate 3D photon impact positioning (including photon Depth of Interaction (DOI) measurement), while providing a precise determination of the photon arrival time to the detector. The detector includes a novel readout system that reduces the number of detector signals in a ratio of 4:1 thus, alleviating complexity and cost. The analog output signals are fed to the TOFPET2 ASIC (PETsys) for scalability purposes.
The present manuscript reports the evaluation of the 4D-PET detector, achieving best values 3D resolution values of <1.6 mm (pixelated axis), 2.7±0.5 mm (monolithic axis) and 3.4±1.1 (DOI axis) mm; 359 ± 7 ps coincidence time resolution (CTR); 10.2±1.5 % energy resolution; and sensitivity of 16.2% at the center of the scanner (simulated). Moreover, a comprehensive description of the 4D-PET architecture (that includes 320 detectors), some pictures of its mechanical assembly, and simulations on the expected image quality are provided.
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20
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A double photon coincidence detection method for medical gamma-ray imaging. BIO-ALGORITHMS AND MED-SYSTEMS 2022. [DOI: 10.2478/bioal-2022-0080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Abstract
Cascade nuclides emit two or more gamma rays successively through an intermediate state. The coincidence detection of cascade gamma rays provides several advantages in gamma-ray imaging. In this review article, three applications of the double photon coincidence method are reviewed. Double-photon emission imaging with mechanical collimators and Compton double-photon emission imaging can identify radioactive source positions with their angular-resolving detectors, and reduce the crosstalk between nuclides. In addition, a novel method of coincidence Compton imaging is proposed by taking coincidence detection between a Compton event and a photopeak events. Although this type of coincidence Compton imaging cannot specify the location, it can be useful in multi-nuclide Compton imaging.
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21
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Quigg M, Kundu B. Dynamic FDG-PET demonstration of functional brain abnormalities. Ann Clin Transl Neurol 2022; 9:1487-1497. [PMID: 36069052 PMCID: PMC9463948 DOI: 10.1002/acn3.51546] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Revised: 03/01/2022] [Accepted: 03/02/2022] [Indexed: 11/27/2022] Open
Abstract
Positron emission tomography with fluorine‐18 fluorodeoxyglucose (18F‐FDG‐PET) has been used over 3 decades to map patterns of brain glucose metabolism to evaluate normal brain function or demonstrate abnormalities of metabolism in brain disorders. Traditional PET maps patterns of absolute tracer uptake but has demonstrated shortcomings in disorders such as brain neoplasm or focal epilepsy in the ability to resolve normally from pathological tissue. In this review, we describe an alternative process of metabolic mapping, dynamic PET. This new technology quantifies the dynamics of tracer uptake and decays with the goal of improving the functional mapping of the desired metabolic activity in the target organ. We discuss technical implementation and findings of initial pilot studies in brain tumor treatment and epilepsy surgery.
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Affiliation(s)
- Mark Quigg
- Department of Neurology, University of Virginia, Charlottesville, Virginia, 22908, USA
| | - Bijoy Kundu
- Departments of Radiology & Medical Imaging and Biomedical Engineering, University of Virginia, Charlottesville, Virginia, USA
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22
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Wang B, Lu L, Liu H. DeTransUnet: attenuation correction of gated cardiac images without structural information. Phys Med Biol 2022; 67. [DOI: 10.1088/1361-6560/ac840e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Accepted: 07/25/2022] [Indexed: 11/11/2022]
Abstract
Abstract
Objective. Myocardial perfusion imaging (MPI) with positron emission tomography (PET) is a non-invasive imaging method, and it is of great significance to the diagnosis and prognosis of coronary heart disease. Attenuation correction (AC) for PET images is a necessary step for further quantitative analysis. In order not to use magnetic resonance (MR) or computed tomography (CT) images for AC, this work proposes DeTransUnet to obtain AC PET images directly from no-attenuation corrected (NAC) PET images. Approach. The proposed DeTransUnet is a 3D structure which combines the multi-scale deformable transformer layers and the 3D convolutional neural network (CNN). And it integrates the advantages of transformer with long-range dependence and CNN suitable for image calculation. The AC images using CT images for AC and scatter correction (SC) and are considered as training labels, while the NAC images are reconstructed without AC and SC. Standard uptake value (SUV) values are calculated for both NAC and AC images to exclude the influence of weight and injection dose. With NAC SUV images as the inputs of the DeTransUnet, the outputs of DeTransUnet are AC SUV images. Main results. The proposed DeTransUnet was performed on an MPI gated-PET dataset, and the results were compared with Unet2D and Unet2.5D. The metrics of the whole image and the left ventricular myocardium show that the proposed method has advantages over other deep learning methods. Significance. The proposed DeTransUnet is a novel AC framework that does not require CT or MR images. It can be used as an independent AC method on PET/MR instrument. In addition, when CT images contain defects or cannot be registered with PET images on PET/CT instrument, DeTransUnet is able to repair the defects and keep consistent with the NAC images.
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23
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Fragoso Costa P, Jentzen W, Brahmer A, Mavroeidi IA, Zarrad F, Umutlu L, Fendler WP, Rischpler C, Herrmann K, Conti M, Seifert R, Sraieb M, Weber M, Kersting D. Phantom-based acquisition time and image reconstruction parameter optimisation for oncologic FDG PET/CT examinations using a digital system. BMC Cancer 2022; 22:899. [PMID: 35978274 PMCID: PMC9387080 DOI: 10.1186/s12885-022-09993-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2021] [Accepted: 08/08/2022] [Indexed: 11/18/2022] Open
Abstract
Background New-generation silicon-photomultiplier (SiPM)-based PET/CT systems exhibit an improved lesion detectability and image quality due to a higher detector sensitivity. Consequently, the acquisition time can be reduced while maintaining diagnostic quality. The aim of this study was to determine the lowest 18F-FDG PET acquisition time without loss of diagnostic information and to optimise image reconstruction parameters (image reconstruction algorithm, number of iterations, voxel size, Gaussian filter) by phantom imaging. Moreover, patient data are evaluated to confirm the phantom results. Methods Three phantoms were used: a soft-tissue tumour phantom, a bone-lung tumour phantom, and a resolution phantom. Phantom conditions (lesion sizes from 6.5 mm to 28.8 mm in diameter, lesion activity concentration of 15 kBq/mL, and signal-to-background ratio of 5:1) were derived from patient data. PET data were acquired on an SiPM-based Biograph Vision PET/CT system for 10 min in list-mode format and resampled into time frames from 30 to 300 s in 30-s increments to simulate different acquisition times. Different image reconstructions with varying iterations, voxel sizes, and Gaussian filters were probed. Contrast-to-noise-ratio (CNR), maximum, and peak signal were evaluated using the 10-min acquisition time image as reference. A threshold CNR value ≥ 5 and a maximum (peak) deviation of ± 20% were considered acceptable. 20 patient data sets were evaluated regarding lesion quantification as well as agreement and correlation between reduced and full acquisition time standard uptake values (assessed by Pearson correlation coefficient, intraclass correlation coefficient, Bland–Altman analyses, and Krippendorff’s alpha). Results An acquisition time of 60 s per bed position yielded acceptable detectability and quantification results for clinically relevant phantom lesions ≥ 9.7 mm in diameter using OSEM-TOF or OSEM-TOF+PSF image reconstruction, a 4-mm Gaussian filter, and a 1.65 × 1.65 x 2.00-mm3 or 3.30 × 3.30 x 3.00-mm3 voxel size. Correlation and agreement of patient lesion quantification between full and reduced acquisition times were excellent. Conclusion A threefold reduction in acquisition time is possible. Patients might benefit from more comfortable examinations or reduced radiation exposure, if instead of the acquisition time the applied activity is reduced. Supplementary Information The online version contains supplementary material available at 10.1186/s12885-022-09993-4.
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Affiliation(s)
- Pedro Fragoso Costa
- Department of Nuclear Medicine, University Hospital Essen, West German Cancer Center (WTZ), University of Duisburg-Essen, Hufelandstrasse 55, 45147, Essen, Germany.,German Cancer Consortium (DKTK), Partner Site University Hospital Essen, Essen, Germany
| | - Walter Jentzen
- Department of Nuclear Medicine, University Hospital Essen, West German Cancer Center (WTZ), University of Duisburg-Essen, Hufelandstrasse 55, 45147, Essen, Germany.,German Cancer Consortium (DKTK), Partner Site University Hospital Essen, Essen, Germany
| | - Alissa Brahmer
- Department of Nuclear Medicine, University Hospital Essen, West German Cancer Center (WTZ), University of Duisburg-Essen, Hufelandstrasse 55, 45147, Essen, Germany.,German Cancer Consortium (DKTK), Partner Site University Hospital Essen, Essen, Germany
| | - Ilektra-Antonia Mavroeidi
- German Cancer Consortium (DKTK), Partner Site University Hospital Essen, Essen, Germany.,Department of Medical Oncology, University Hospital Essen, West German Cancer Center (WTZ), University Duisburg-Essen, 45147, Essen, Germany
| | - Fadi Zarrad
- Department of Nuclear Medicine, University Hospital Essen, West German Cancer Center (WTZ), University of Duisburg-Essen, Hufelandstrasse 55, 45147, Essen, Germany.,German Cancer Consortium (DKTK), Partner Site University Hospital Essen, Essen, Germany
| | - Lale Umutlu
- German Cancer Consortium (DKTK), Partner Site University Hospital Essen, Essen, Germany.,Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, University Duisburg-Essen, 45147, Essen, Germany
| | - Wolfgang P Fendler
- Department of Nuclear Medicine, University Hospital Essen, West German Cancer Center (WTZ), University of Duisburg-Essen, Hufelandstrasse 55, 45147, Essen, Germany.,German Cancer Consortium (DKTK), Partner Site University Hospital Essen, Essen, Germany
| | - Christoph Rischpler
- Department of Nuclear Medicine, University Hospital Essen, West German Cancer Center (WTZ), University of Duisburg-Essen, Hufelandstrasse 55, 45147, Essen, Germany.,German Cancer Consortium (DKTK), Partner Site University Hospital Essen, Essen, Germany
| | - Ken Herrmann
- Department of Nuclear Medicine, University Hospital Essen, West German Cancer Center (WTZ), University of Duisburg-Essen, Hufelandstrasse 55, 45147, Essen, Germany.,German Cancer Consortium (DKTK), Partner Site University Hospital Essen, Essen, Germany
| | | | - Robert Seifert
- Department of Nuclear Medicine, University Hospital Essen, West German Cancer Center (WTZ), University of Duisburg-Essen, Hufelandstrasse 55, 45147, Essen, Germany.,German Cancer Consortium (DKTK), Partner Site University Hospital Essen, Essen, Germany
| | - Miriam Sraieb
- Department of Nuclear Medicine, University Hospital Essen, West German Cancer Center (WTZ), University of Duisburg-Essen, Hufelandstrasse 55, 45147, Essen, Germany.,German Cancer Consortium (DKTK), Partner Site University Hospital Essen, Essen, Germany
| | - Manuel Weber
- Department of Nuclear Medicine, University Hospital Essen, West German Cancer Center (WTZ), University of Duisburg-Essen, Hufelandstrasse 55, 45147, Essen, Germany.,German Cancer Consortium (DKTK), Partner Site University Hospital Essen, Essen, Germany
| | - David Kersting
- Department of Nuclear Medicine, University Hospital Essen, West German Cancer Center (WTZ), University of Duisburg-Essen, Hufelandstrasse 55, 45147, Essen, Germany. .,German Cancer Consortium (DKTK), Partner Site University Hospital Essen, Essen, Germany.
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24
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Hosch R, Weber M, Sraieb M, Flaschel N, Haubold J, Kim MS, Umutlu L, Kleesiek J, Herrmann K, Nensa F, Rischpler C, Koitka S, Seifert R, Kersting D. Artificial intelligence guided enhancement of digital PET: scans as fast as CT? Eur J Nucl Med Mol Imaging 2022; 49:4503-4515. [PMID: 35904589 PMCID: PMC9606065 DOI: 10.1007/s00259-022-05901-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 06/30/2022] [Indexed: 12/03/2022]
Abstract
Purpose Both digital positron emission tomography (PET) detector technologies and artificial intelligence based image post-reconstruction methods allow to reduce the PET acquisition time while maintaining diagnostic quality. The aim of this study was to acquire ultra-low-count fluorodeoxyglucose (FDG) ExtremePET images on a digital PET/computed tomography (CT) scanner at an acquisition time comparable to a CT scan and to generate synthetic full-dose PET images using an artificial neural network. Methods This is a prospective, single-arm, single-center phase I/II imaging study. A total of 587 patients were included. For each patient, a standard and an ultra-low-count FDG PET/CT scan (whole-body acquisition time about 30 s) were acquired. A modified pix2pixHD deep-learning network was trained employing 387 data sets as training and 200 as test cohort. Three models (PET-only and PET/CT with or without group convolution) were compared. Detectability and quantification were evaluated. Results The PET/CT input model with group convolution performed best regarding lesion signal recovery and was selected for detailed evaluation. Synthetic PET images were of high visual image quality; mean absolute lesion SUVmax (maximum standardized uptake value) difference was 1.5. Patient-based sensitivity and specificity for lesion detection were 79% and 100%, respectively. Not-detected lesions were of lower tracer uptake and lesion volume. In a matched-pair comparison, patient-based (lesion-based) detection rate was 89% (78%) for PERCIST (PET response criteria in solid tumors)-measurable and 36% (22%) for non PERCIST-measurable lesions. Conclusion Lesion detectability and lesion quantification were promising in the context of extremely fast acquisition times. Possible application scenarios might include re-staging of late-stage cancer patients, in whom assessment of total tumor burden can be of higher relevance than detailed evaluation of small and low-uptake lesions. Supplementary Information The online version contains supplementary material available at 10.1007/s00259-022-05901-x.
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Affiliation(s)
- René Hosch
- Institute of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Hufelandstraße 55, 45147, Essen, Germany. .,Institute for Artificial Intelligence in Medicine (IKIM), University Hospital Essen, Girardetstraße 2, 45131, Essen, Germany.
| | - Manuel Weber
- Department of Nuclear Medicine and German Cancer Consortium (DKTK), University Hospital Essen, University of Duisburg-Essen, Hufelandstraße 55, 45147, Essen, Germany
| | - Miriam Sraieb
- Department of Nuclear Medicine and German Cancer Consortium (DKTK), University Hospital Essen, University of Duisburg-Essen, Hufelandstraße 55, 45147, Essen, Germany
| | - Nils Flaschel
- Institute of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Hufelandstraße 55, 45147, Essen, Germany.,Institute for Artificial Intelligence in Medicine (IKIM), University Hospital Essen, Girardetstraße 2, 45131, Essen, Germany
| | - Johannes Haubold
- Institute of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Hufelandstraße 55, 45147, Essen, Germany
| | - Moon-Sung Kim
- Institute of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Hufelandstraße 55, 45147, Essen, Germany.,Institute for Artificial Intelligence in Medicine (IKIM), University Hospital Essen, Girardetstraße 2, 45131, Essen, Germany
| | - Lale Umutlu
- Institute of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Hufelandstraße 55, 45147, Essen, Germany
| | - Jens Kleesiek
- Institute for Artificial Intelligence in Medicine (IKIM), University Hospital Essen, Girardetstraße 2, 45131, Essen, Germany
| | - Ken Herrmann
- Department of Nuclear Medicine and German Cancer Consortium (DKTK), University Hospital Essen, University of Duisburg-Essen, Hufelandstraße 55, 45147, Essen, Germany
| | - Felix Nensa
- Institute of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Hufelandstraße 55, 45147, Essen, Germany.,Institute for Artificial Intelligence in Medicine (IKIM), University Hospital Essen, Girardetstraße 2, 45131, Essen, Germany
| | - Christoph Rischpler
- Department of Nuclear Medicine and German Cancer Consortium (DKTK), University Hospital Essen, University of Duisburg-Essen, Hufelandstraße 55, 45147, Essen, Germany
| | - Sven Koitka
- Institute of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Hufelandstraße 55, 45147, Essen, Germany.,Institute for Artificial Intelligence in Medicine (IKIM), University Hospital Essen, Girardetstraße 2, 45131, Essen, Germany
| | - Robert Seifert
- Department of Nuclear Medicine and German Cancer Consortium (DKTK), University Hospital Essen, University of Duisburg-Essen, Hufelandstraße 55, 45147, Essen, Germany.,Department of Nuclear Medicine, University Hospital Münster, University of Münster, Albert-Schweitzer-Campus 1, 48149, Münster, Germany
| | - David Kersting
- Department of Nuclear Medicine and German Cancer Consortium (DKTK), University Hospital Essen, University of Duisburg-Essen, Hufelandstraße 55, 45147, Essen, Germany
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Karakatsanis NA, Nehmeh MH, Conti M, Bal G, González AJ, Nehmeh SA. Physical performance of adaptive axial FOV PET scanners with a sparse detector block rings or a checkerboard configuration. Phys Med Biol 2022; 67. [DOI: 10.1088/1361-6560/ac6aa1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 04/26/2022] [Indexed: 11/12/2022]
Abstract
Abstract
Objective. Using Monte-Carlo simulations, we evaluated the physical performance of a hypothetical state-of-the-art clinical PET scanner with adaptive axial field-of-view (AFOV) based on the validated GATE model of the Siemens Biograph VisionTM PET/CT scanner. Approach. Vision consists of 16 compact PET rings, each consisting of 152 mini-blocks of 5 × 5 Lutetium Oxyorthosilicate crystals (3.2 × 3.2 × 20 mm3). The Vision 25.6 cm AFOV was extended by adopting (i) a sparse mini-block ring (SBR) configuration of 49.6 cm AFOV, with all mini-block rings interleaved with 16 mm axial gaps, or (ii) a sparse mini-block checkerboard (SCB) configuration of 51.2 cm AFOV, with all mini-blocks interleaved with gaps of 16 mm (transaxial) × 16 mm (axial) width in checkerboard pattern. For sparse configurations, a ‘limited’ continuous bed motion (limited-CBM) acquisition was employed to extend AFOVs by 2.9 cm. Spatial resolution, sensitivity, image quality (IQ), NECR and scatter fraction were assessed per NEMA NU2-2012. Main Results. All IQ phantom spheres were distinguishable with all configurations. SBR and SCB percent contrast recovery (% CR) and background variability (% BV) were similar (p-value > 0.05). Compared to Vision, SBR and SCB %CRs were similar (p-values > 0.05). However, SBR and SCB %BVs were deteriorated by 30% and 26% respectively (p-values < 0.05). SBR, SCB and Vision exhibited system sensitivities of 16.6, 16.8, and 15.8 kcps MBq−1, NECRs of 311 kcps @35 kBq cc−1, 266 kcps @25.8 kBq cc−1, and 260 kcps @27.8 kBq cc−1, and scatter fractions of 31.2%, 32.4%, and 32.6%, respectively. SBR and SCB exhibited a smoother sensitivity reduction and noise enhancement rate from AFOV center to its edges. SBR and SCB attained comparable spatial resolution in all directions (p-value > 0.05), yet, up to 1.5 mm worse than Vision (p-values < 0.05). Significance. The proposed sparse configurations may offer a clinically adoptable solution for cost-effective adaptive AFOV PET with either highly-sensitive or long-AFOV acquisitions.
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Artificial intelligence-based PET denoising could allow a two-fold reduction in [ 18F]FDG PET acquisition time in digital PET/CT. Eur J Nucl Med Mol Imaging 2022; 49:3750-3760. [PMID: 35593925 PMCID: PMC9399218 DOI: 10.1007/s00259-022-05800-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Accepted: 04/10/2022] [Indexed: 11/18/2022]
Abstract
Purpose We investigated whether artificial intelligence (AI)-based denoising halves PET acquisition time in digital PET/CT. Methods One hundred ninety-five patients referred for [18F]FDG PET/CT were prospectively included. Body PET acquisitions were performed in list mode. Original “PET90” (90 s/bed position) was compared to reconstructed ½-duration PET (45 s/bed position) with and without AI-denoising, “PET45AI and PET45”. Denoising was performed by SubtlePET™ using deep convolutional neural networks. Visual global image quality (IQ) 3-point scores and lesion detectability were evaluated. Lesion maximal and peak standardized uptake values using lean body mass (SULmax and SULpeak), metabolic volumes (MV), and liver SULmean were measured, including both standard and EARL1 (European Association of Nuclear Medicine Research Ltd) compliant SUL. Lesion-to-liver SUL ratios (LLR) and liver coefficients of variation (CVliv) were calculated. Results PET45 showed mediocre IQ (scored poor in 8% and moderate in 68%) and lesion concordance rate with PET90 (88.7%). In PET45AI, IQ scores were similar to PET90 (P = 0.80), good in 92% and moderate in 8% for both. The lesion concordance rate between PET90 and PET45AI was 836/856 (97.7%), with 7 lesions (0.8%) only detected in PET90 and 13 (1.5%) exclusively in PET45AI. Lesion EARL1 SULpeak was not significantly different between both PET (P = 0.09). Lesion standard SULpeak, standard and EARL1 SULmax, LLR and CVliv were lower in PET45AI than in PET90 (P < 0.0001), while lesion MV and liver SULmean were higher (P < 0.0001). Good to excellent intraclass correlation coefficients (ICC) between PET90 and PET45AI were observed for lesion SUL and MV (ICC ≥ 0.97) and for liver SULmean (ICC ≥ 0.87). Conclusion AI allows [18F]FDG PET duration in digital PET/CT to be halved, while restoring degraded ½-duration PET image quality. Future multicentric studies, including other PET radiopharmaceuticals, are warranted. Supplementary Information The online version contains supplementary material available at 10.1007/s00259-022-05800-1.
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Are Quantitative Errors Reduced with Time-of-Flight Reconstruction When Using Imperfect MR-Based Attenuation Maps for 18F-FDG PET/MR Neuroimaging? APPLIED SCIENCES-BASEL 2022. [DOI: 10.3390/app12094605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
We studied whether TOF reduces error propagation from attenuation correction to PET image reconstruction in PET/MR neuroimaging, by using imperfect attenuation maps in a clinical PET/MR system with 525 ps timing resolution. Ten subjects who had undergone 18F-FDG PET neuroimaging were included. Attenuation maps using a single value (0.100 cm−1) with and without air, and a 3-class attenuation map with soft tissue (0.096 cm−1), air and bone (0.151 cm−1) were used. CT-based attenuation correction was used as a reference. Volume-of-interest (VOI) analysis was conducted. Mean bias and standard deviation across the brain was studied. Regional correlations and concordance were evaluated. Statistical testing was conducted. Average bias and standard deviation were slightly reduced in the majority (23–26 out of 35) of the VOI with TOF. Bias was reduced near the cortex, nasal sinuses, and in the mid-brain with TOF. Bland–Altman and regression analysis showed small improvements with TOF. However, the overall effect of TOF to quantitative accuracy was small (3% at maximum) and significant only for two attenuation maps out of three at 525 ps timing resolution. In conclusion, TOF might reduce the quantitative errors due to attenuation correction in PET/MR neuroimaging, but this effect needs to be further investigated on systems with better timing resolution.
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Zarif Yussefian N, Gaudin E, Lecomte R, Fontaine R. Predicting Small Lesion Detectability for a Small Animal TOF PET Scanner. IEEE TRANSACTIONS ON RADIATION AND PLASMA MEDICAL SCIENCES 2022. [DOI: 10.1109/trpms.2021.3105945] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Nikta Zarif Yussefian
- Department of Electrical and Computer Engineering and the Interdisciplinary Institute for Technological Innovation 3IT, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Emilie Gaudin
- Sherbrooke Molecular Imaging Center and the Department of Nuclear Medicine and Radiobiology, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Roger Lecomte
- Sherbrooke Molecular Imaging Center and the Department of Nuclear Medicine and Radiobiology, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Rejean Fontaine
- Department of Electrical and Computer Engineering and the Interdisciplinary Institute for Technological Innovation 3IT, Université de Sherbrooke, Sherbrooke, QC, Canada
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Wimalarathne D, Ruan W, Sun X, Liu F, Gai Y, Liu Q, Hu F, Lan X. Impact of TOF on Brain PET With Short-Lived 11C-Labeled Tracers Among Suspected Patients With AD/PD: Using Hybrid PET/MRI. Front Med (Lausanne) 2022; 9:823292. [PMID: 35308534 PMCID: PMC8926006 DOI: 10.3389/fmed.2022.823292] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2021] [Accepted: 01/12/2022] [Indexed: 11/13/2022] Open
Abstract
Objective To explore the impact of the time-of-flight (TOF) reconstruction on brain PET with short-lived 11C-labeled tracers in PET magnetic resonance (PET/MR) brain images among suspected patients with Alzheimer's and Parkinson's disease (AD/PD). Methods Patients who underwent 11C-2-ß-carbomethoxy-3-b-(4-fluorophenyl) tropane (11C-CFT) and 2-(4-N-[11C] methylaminophenyl)-6-hydroxybenzothiazole (11C-PiB) PET/MRI were retrospectively included in the study. Each PET LIST mode data were reconstructed with and without the TOF reconstruction algorithm. Standard uptake values (SUVs) of Caudate Nucleus (CN), Putamen (PU), and Whole-brain (WB) were measured. TOF and non-TOF SUVs were assessed by using paired t-test. Standard formulas were applied to measure contrast, signal-to-noise ratio (SNR), and percentage relative average difference of SUVs (%RAD-SUVs). Results Total 75 patients were included with the median age (years) and body mass index (BMI-kg/m2) of 60.2 ± 10.9 years and 23.9 ± 3.7 kg/m2 in 11C-CFT (n = 41) and 62.2 ± 6.8 years and 24.7 ± 2.9 kg/m2 in 11C-PiB (n = 34), respectively. Higher average SUVs and positive %RAD-SUVs were observed in CN and PU in TOF compared with non-TOF reconstructions for the two 11C-labeled radiotracers. Differences of SUVmean were significant (p < 0.05) in CN and PU for both 11C-labeled radiotracers. SUVmax was enhanced significantly in CN and PU for 11C-CFT and CN for 11C-PiB, but not in PU. Significant contrast enhancement was observed in PU for both 11C-labeled radiotracers, whereas SNR gain was significant in PU, only for 11C-PiB in TOF reconstruction. Conclusion Time-of-flight leads to a better signal vs. noise trade-off than non-TOF in 11C-labeled tracers between CN and PU, improving the SUVs, contrast, and SNR, which were valuable for reducing injected radiation dose. Improved timing resolution aided the rapid decay rate of short-lived 11C-labeled tracers, and it shortened the scan time, increasing the patient comfort, and reducing the motion artifact among patients with AD/PD. However, one should adopt the combined TOF algorithm with caution for the quantitative analysis because it has different effects on the SUVmax, contrast, and SNR of different brain regions.
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Affiliation(s)
- D.D.N Wimalarathne
- Department of Nuclear Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Province Key Laboratory of Molecular Imaging, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Department of Radiography and Radiotherapy, Faculty of Allied Health Sciences, General Sir John Kotelawala Defence University, Rathmalana, Sri Lanka
| | - Weiwei Ruan
- Department of Nuclear Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Province Key Laboratory of Molecular Imaging, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xun Sun
- Department of Nuclear Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Province Key Laboratory of Molecular Imaging, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Fang Liu
- Department of Nuclear Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Province Key Laboratory of Molecular Imaging, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yongkang Gai
- Department of Nuclear Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Province Key Laboratory of Molecular Imaging, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Qingyao Liu
- Department of Nuclear Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Province Key Laboratory of Molecular Imaging, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Fan Hu
- Department of Nuclear Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Province Key Laboratory of Molecular Imaging, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xiaoli Lan
- Department of Nuclear Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Province Key Laboratory of Molecular Imaging, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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Leem H, Choi Y, Jung J, Park K, Kim Y, Jung JH. Optimized TOF-PET detector using scintillation crystal array for brain imaging. NUCLEAR ENGINEERING AND TECHNOLOGY 2022. [DOI: 10.1016/j.net.2022.02.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Lecoq P, Konstantinou G, Latella R, Moliner L, Nuyts J, Zhang L, Barrio J, Benlloch JM, Gonzalez AJ. Metascintillators: New results for TOFPET applications. IEEE TRANSACTIONS ON RADIATION AND PLASMA MEDICAL SCIENCES 2022. [DOI: 10.1109/trpms.2022.3161473] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Seifert R, Kersting D, Rischpler C, Opitz M, Kirchner J, Pabst KM, Mavroeidi IA, Laschinsky C, Grueneisen J, Schaarschmidt B, Catalano OA, Herrmann K, Umutlu L. Clinical Use of PET/MR in Oncology: An Update. Semin Nucl Med 2021; 52:356-364. [PMID: 34980479 DOI: 10.1053/j.semnuclmed.2021.11.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Revised: 11/21/2021] [Accepted: 11/23/2021] [Indexed: 12/30/2022]
Abstract
The combination of PET and MRI is one of the recent advances of hybrid imaging. Yet to date, the adoption rate of PET/MRI systems has been rather slow. This seems to be partially caused by the high costs of PET/MRI systems and the need to verify an incremental benefit over PET/CT or sequential PET/CT and MRI. In analogy to PET/CT, the MRI part of PET/MRI was primarily used for anatomical imaging. Though this can be advantageous, for example in diseases where the superior soft tissue contrast of MRI is highly appreciated, the sole use of MRI for anatomical orientation lessens the potential of PET/MRI. Consequently, more recent studies focused on its multiparametric potential and employed diffusion weighted sequences and other functional imaging sequences in PET/MRI. This integration puts the focus on a more wholesome approach to PET/MR imaging, in terms of releasing its full potential for local primary staging based on multiparametric imaging and an included one-stop shop approach for whole-body staging. This approach as well as the implementation of computational analysis, in terms of radiomics analysis, has been shown valuable in several oncological diseases, as will be discussed in this review article.
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Affiliation(s)
- Robert Seifert
- Department of Nuclear Medicine, University Hospital Essen, Essen, Germany; Department of Nuclear Medicine, University Hospital Münster, Münster, Germany; West German Cancer Center, University Hospital Essen, Essen, Germany.; German Cancer Consortium (DKTK), University Hospital Essen, Essen, Germany.
| | - David Kersting
- Department of Nuclear Medicine, University Hospital Essen, Essen, Germany; West German Cancer Center, University Hospital Essen, Essen, Germany.; German Cancer Consortium (DKTK), University Hospital Essen, Essen, Germany
| | - Christoph Rischpler
- Department of Nuclear Medicine, University Hospital Essen, Essen, Germany; West German Cancer Center, University Hospital Essen, Essen, Germany.; German Cancer Consortium (DKTK), University Hospital Essen, Essen, Germany
| | - Marcel Opitz
- Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Essen, Germany
| | - Julian Kirchner
- Department of Diagnostic and Interventional Radiology, University Dusseldorf, Medical Faculty, Dusseldorf, Germany
| | - Kim M Pabst
- Department of Nuclear Medicine, University Hospital Essen, Essen, Germany; West German Cancer Center, University Hospital Essen, Essen, Germany.; German Cancer Consortium (DKTK), University Hospital Essen, Essen, Germany
| | - Ilektra-Antonia Mavroeidi
- West German Cancer Center, University Hospital Essen, Essen, Germany.; Clinic for Internal Medicine (Tumor Research), University Hospital Essen, Essen, Germany
| | - Christina Laschinsky
- Department of Nuclear Medicine, University Hospital Essen, Essen, Germany; West German Cancer Center, University Hospital Essen, Essen, Germany.; German Cancer Consortium (DKTK), University Hospital Essen, Essen, Germany
| | - Johannes Grueneisen
- Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Essen, Germany
| | - Benedikt Schaarschmidt
- Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Essen, Germany
| | - Onofrio Antonio Catalano
- Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA; Abdominal Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA
| | - Ken Herrmann
- Department of Nuclear Medicine, University Hospital Essen, Essen, Germany; West German Cancer Center, University Hospital Essen, Essen, Germany.; German Cancer Consortium (DKTK), University Hospital Essen, Essen, Germany
| | - Lale Umutlu
- Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Essen, Germany
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Kratochwil N, Gundacker S, Auffray E. A roadmap for sole Cherenkov radiators with SiPMs in TOF-PET. Phys Med Biol 2021; 66. [PMID: 34433139 DOI: 10.1088/1361-6560/ac212a] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Accepted: 08/25/2021] [Indexed: 11/11/2022]
Abstract
Time of flight positron emission tomography can strongly benefit from a very accurate time estimator given by Cherenkov radiation, which is produced upon a 511 keV positron-electron annihilation gamma interaction in heavy inorganic scintillators. While time resolution in the order of 30 ps full width at half maximum (FWHM) has been reported using MCP-PMTs and black painted Cherenkov radiators, such solutions have several disadvantages, like high cost and low detection efficiency of nowadays available MCP-PMTs. On the other hand, silicon photomultipliers (SiPMs) are not limited by those obstacles and provide high photon detection efficiency with a decent time response. Timing performance of PbF2crystals of various lengths and surface conditions coupled to SiPMs was evaluated against a reference detector with an optimized test setup using high-frequency readout and novel time walk correction, with special attention on the intrinsic limits for one detected Cherenkov photon only. The average number of detected Cherenkov photons largely depends on the crystal surface state, resulting in a tradeoff between low photon time spread, thus good timing performance, and sensitivity. An intrinsic Cherenkov photon yield of 16.5 ± 3.3 was calculated for 2 × 2 × 3 mm3sized PbF2crystals upon 511 keVγ-deposition. After time walk correction based on the slew rate of the signal, assuming two identical detector arms in coincidence, and using all events, a time resolution of 215 ps FWHM (142 ps FWHM) was obtained for 2 × 2 × 20 mm3(2 × 2 × 3 mm3) sized PbF2crystals, compared to 261 ps (190 ps) without correction. Selecting on one detected photon only, a single photon coincidence time resolution of 113 ps FWHM for black painted and 166 ps for Teflon wrapped crystals was measured for 3 mm length, compared to 145 ps (black) and 263 ps (Teflon) for 20 mm length.
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Affiliation(s)
- Nicolaus Kratochwil
- CERN, Esplanade des Particules 1, 1211 Meyrin, Switzerland.,University of Vienna, Universitaetsring 1, A-1010 Vienna, Austria
| | - Stefan Gundacker
- CERN, Esplanade des Particules 1, 1211 Meyrin, Switzerland.,Department of Physics of Molecular Imaging Systems, Institute for Experimental Molecular Imaging, RWTH Aachen University, Forckenbeckstrasse 55, D-52074 Aachen, Germany
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Gonzalez-Montoro A, Pourashraf S, Lee MS, Cates JW, Levin CS. Study of optical reflectors for a 100ps coincidence time resolution TOF-PET detector design. Biomed Phys Eng Express 2021; 7:10.1088/2057-1976/ac240e. [PMID: 34488203 PMCID: PMC8548986 DOI: 10.1088/2057-1976/ac240e] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Accepted: 09/06/2021] [Indexed: 01/05/2023]
Abstract
Positron Emission Tomography (PET) reconstructed image signal-to-noise ratio (SNR) can be improved by including the 511 keV photon pair coincidence time-of-flight (TOF) information. The degree of SNR improvement from this TOF capability depends on the coincidence time resolution (CTR) of the PET system, which is essentially the variation in photon arrival time differences over all coincident photon pairs detected for a point positron source placed at the system center. The CTR is determined by several factors including the intrinsic properties of the scintillation crystals and photodetectors, crystal-to-photodetector coupling configurations, reflective materials, and the electronic readout configuration scheme. The goal of the present work is to build a novel TOF-PET system with 100 picoseconds (ps) CTR, which provides an additional factor of 1.5-2.0 improvement in reconstructed image SNR compared to state-of-the-art TOF-PET systems which achieve 225-400 ps CTR. A critical parameter to understand is the optical reflector's influence on scintillation light collection and transit time variations to the photodetector. To study the effects of the reflector covering the scintillation crystal element on CTR, we have tested the performance of four different reflector materials: Enhanced Specular Reflector (ESR) -coupled with air or optical grease to the scintillator; Teflon tape; BaSO4paint alone or mixed with epoxy; and TiO2paint. For the experimental set-up, we made use of 3 × 3 × 10 mm3fast-LGSO:Ce scintillation crystal elements coupled to an array of silicon photomultipliers (SiPMs) using a novel 'side-readout' configuration that has proven to have lower variations in scintillation light collection efficiency and transit time to the photodetector.Results: show CTR values of 102.0 ± 0.8, 100.2 ± 1.2, 97.3 ± 1.8 and 95.0 ± 1.0 ps full-width-half-maximum (FWHM) with non-calibrated energy resolutions of 10.2 ± 1.8, 9.9 ± 1.2, 7.9 ± 1.2, and 8.6 ± 1.7% FWHM for the Teflon, ESR (without grease), BaSO4(without epoxy) and TiO2paint treatments, respectively.
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Affiliation(s)
- Andrea Gonzalez-Montoro
- Department of Radiology, Molecular Imaging Program at Stanford, School of Medicine, Stanford University, California, United States of America
| | - Shirin Pourashraf
- Department of Radiology, Molecular Imaging Program at Stanford, School of Medicine, Stanford University, California, United States of America
| | - Min Sun Lee
- Department of Radiology, Molecular Imaging Program at Stanford, School of Medicine, Stanford University, California, United States of America
- Nuclear Emergency & Environmental Protection Division, Korea Atomic Energy Research Institute, Daejeon, Republic of Korea
| | - Joshua W Cates
- Applied Nuclear Physics Program, Lawrence Berkeley National Laboratory, California, United States of America
| | - Craig S Levin
- Department of Radiology, Molecular Imaging Program at Stanford, School of Medicine, Stanford University, California, United States of America
- Department of Physics, Stanford University, California, United States of America
- Department of Electrical Engineering, Stanford University, California, United States of America
- Department of Bioengineering, Stanford University, California, United States of America
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Kratochwil N, Auffray E, Gundacker S. Exploring Cherenkov Emission of BGO for TOF-PET. IEEE TRANSACTIONS ON RADIATION AND PLASMA MEDICAL SCIENCES 2021. [DOI: 10.1109/trpms.2020.3030483] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Kersting D, Jentzen W, Fragoso Costa P, Sraieb M, Sandach P, Umutlu L, Conti M, Zarrad F, Rischpler C, Fendler WP, Herrmann K, Weber M. Silicon-photomultiplier-based PET/CT reduces the minimum detectable activity of iodine-124. Sci Rep 2021; 11:17477. [PMID: 34471170 PMCID: PMC8410931 DOI: 10.1038/s41598-021-95719-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Accepted: 07/29/2021] [Indexed: 02/03/2023] Open
Abstract
The radioiodine isotope pair 124I/131I is used in a theranostic approach for patient-specific treatment of differentiated thyroid cancer. Lesion detectability is notably higher for 124I PET (positron emission tomography) than for 131I gamma camera imaging but can be limited for small and low uptake lesions. The recently introduced silicon-photomultiplier-based (SiPM-based) PET/CT (computed tomography) systems outperform previous-generation systems in detector sensitivity, coincidence time resolution, and spatial resolution. Hence, SiPM-based PET/CT shows an improved detectability, particularly for small lesions. In this study, we compare the size-dependant minimum detectable 124I activity (MDA) between the SiPM-based Biograph Vision and the previous-generation Biograph mCT PET/CT systems and we attempt to predict the response to 131I radioiodine therapy of lesions additionally identified on the SiPM-based system. A tumour phantom mimicking challenging conditions (derived from published patient data) was used; i.e., 6 small spheres (diameter of 3.7-9.7 mm), 9 low activity concentrations (0.25-25 kBq/mL), and a very low signal-to-background ratio (20:1). List-mode emission data (single-bed position) were divided into frames of 4, 8, 16, and 30 min. Images were reconstructed with ordinary Poisson ordered-subsets expectation maximization (OSEM), additional time-of-flight (OSEM-TOF) or TOF and point spread function modelling (OSEM-TOF+PSF). The signal-to-noise ratio and the MDA were determined. Absorbed dose estimations were performed to assess possible treatment response to high-activity 131I radioiodine therapy. The signal-to-noise ratio and the MDA were improved from the mCT to the Vision, from OSEM to OSEM-TOF and from OSEM-TOF to OSEM-TOF+PSF reconstructed images, and from shorter to longer emission times. The overall mean MDA ratio of the Vision to the mCT was 0.52 ± 0.18. The absorbed dose estimations indicate that lesions ≥ 6.5 mm with expected response to radioiodine therapy would be detectable on both systems at 4-min emission time. Additional smaller lesions of therapeutic relevance could be detected when using a SiPM-based PET system at clinically reasonable emission times. This study demonstrates that additional lesions with predicted response to 131I radioiodine therapy can be detected. Further clinical evaluation is warranted to evaluate if negative 124I PET scans on a SiPM-based system can be sufficient to preclude patients from blind radioiodine therapy.
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Affiliation(s)
- David Kersting
- Department of Nuclear Medicine, University Hospital Essen, University of Duisburg-Essen, Hufelandstrasse 55, 45147, Essen, Germany.
- German Cancer Consortium (DKTK, Partner Site Essen), Essen, Germany.
| | - Walter Jentzen
- Department of Nuclear Medicine, University Hospital Essen, University of Duisburg-Essen, Hufelandstrasse 55, 45147, Essen, Germany
- German Cancer Consortium (DKTK, Partner Site Essen), Essen, Germany
| | - Pedro Fragoso Costa
- Department of Nuclear Medicine, University Hospital Essen, University of Duisburg-Essen, Hufelandstrasse 55, 45147, Essen, Germany
- German Cancer Consortium (DKTK, Partner Site Essen), Essen, Germany
| | - Miriam Sraieb
- Department of Nuclear Medicine, University Hospital Essen, University of Duisburg-Essen, Hufelandstrasse 55, 45147, Essen, Germany
- German Cancer Consortium (DKTK, Partner Site Essen), Essen, Germany
| | - Patrick Sandach
- Department of Nuclear Medicine, University Hospital Essen, University of Duisburg-Essen, Hufelandstrasse 55, 45147, Essen, Germany
- German Cancer Consortium (DKTK, Partner Site Essen), Essen, Germany
| | - Lale Umutlu
- Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
- German Cancer Consortium (DKTK, Partner Site Essen), Essen, Germany
| | | | - Fadi Zarrad
- Department of Nuclear Medicine, University Hospital Essen, University of Duisburg-Essen, Hufelandstrasse 55, 45147, Essen, Germany
- German Cancer Consortium (DKTK, Partner Site Essen), Essen, Germany
| | - Christoph Rischpler
- Department of Nuclear Medicine, University Hospital Essen, University of Duisburg-Essen, Hufelandstrasse 55, 45147, Essen, Germany
- German Cancer Consortium (DKTK, Partner Site Essen), Essen, Germany
| | - Wolfgang Peter Fendler
- Department of Nuclear Medicine, University Hospital Essen, University of Duisburg-Essen, Hufelandstrasse 55, 45147, Essen, Germany
- German Cancer Consortium (DKTK, Partner Site Essen), Essen, Germany
| | - Ken Herrmann
- Department of Nuclear Medicine, University Hospital Essen, University of Duisburg-Essen, Hufelandstrasse 55, 45147, Essen, Germany
- German Cancer Consortium (DKTK, Partner Site Essen), Essen, Germany
| | - Manuel Weber
- Department of Nuclear Medicine, University Hospital Essen, University of Duisburg-Essen, Hufelandstrasse 55, 45147, Essen, Germany
- German Cancer Consortium (DKTK, Partner Site Essen), Essen, Germany
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Dynamic FDG-PET in localization of focal epilepsy: A pilot study. Epilepsy Behav 2021; 122:108204. [PMID: 34311181 PMCID: PMC8436183 DOI: 10.1016/j.yebeh.2021.108204] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Accepted: 06/29/2021] [Indexed: 11/22/2022]
Abstract
Epilepsy surgery remains underutilized, in part because non-invasive methods of potential seizure foci localization are inadequate. We used high-resolution, parametric quantification from dynamic 2-[18F] fluoro-2-deoxy-d-glucose positron emission tomography (dFDG-PET) imaging to locate hypometabolic foci in patients whose standard clinical static PET images were normal. We obtained dFDG-PET brain images with simultaneous EEG in a one-hour acquisition on seven patients with no MRI evidence of focal epilepsy to record uptake and focal radiation decay. Images were attenuation- and motion-corrected and co-registered with high-resolution T1-weighted patient MRI and segmented into 18 regions of interest (ROI) per hemisphere. Tracer uptake was calibrated with a model corrected blood input function with partial volume (PV) corrections to generate tracer parametric maps compared between mean radiation values between hemispheres with z-scores. We identified ROI with the lowest negative z scores (<-1.65 SD) as hypometabolic. Dynamic 2-[18F] fluoro-2-deoxy-d-glucose positron emission tomography ( found focal regions of altered metabolism in all cases in which standard clinical FDG-PET found no abnormalities. This pilot study of dynamic FDG-PET suggests that further research is merited to evaluate whether glucose dynamics offer improved clinical utility for localization of epileptic foci over standard static techniques.
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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: 113] [Impact Index Per Article: 37.7] [Reference Citation Analysis] [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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LaBella A, Zhao W, Goldan AH. Nanopattern multi-well avalanche selenium detector for TOF-PET. Phys Med Biol 2021; 66:10.1088/1361-6560/abe3d0. [PMID: 33545696 PMCID: PMC11025682 DOI: 10.1088/1361-6560/abe3d0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Accepted: 02/01/2021] [Indexed: 11/11/2022]
Abstract
For the first time, we propose using amorphous selenium (a-Se) as the photoconductive material for time-of-flight (TOF) detectors. Advantages of avalanche-modea-Se are having high fill factor, low excess noise due to unipolar photoconductive gain, band transport in extended states with the highest possible mobility, and negligible trapping. The major drawback ofa-Se is its poor single-photon time resolution and low carrier mobility due to shallow-traps, problems that must be circumvented for TOF applications. We propose a nanopattern multi-wella-Se detector (MWSD) to enable both impact ionization avalanche gain and unipolar time-differential (UTD) charge sensing in one device. Our experimental results show that UTD charge sensing in avalanche-modea-Se improves time-resolution by nearly 4 orders-of-magnitude. In addition, we used Cramér-Rao lower bound analysis and Monte Carlo simulations to demonstrate the viability of our MWSD for low statistics photon imaging modalities such as PET despite it being a linear-mode device. Based on our results, our device may achieve 100 ps coincidence time resolution in TOF PET with a material that is low cost and uniformly scalable to large area.
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Affiliation(s)
- Andy LaBella
- Department of Radiology, Stony Brook University, Stony Brook, NY, United States of America
| | - Wei Zhao
- Department of Radiology, Stony Brook University, Stony Brook, NY, United States of America
| | - Amir H Goldan
- Department of Radiology, Stony Brook University, Stony Brook, NY, United States of America
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40
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Binder T, Kang HG, Nitta M, Schneider F, Yamaya T, Parodi K, Wiest F, Thirolf PG. Performance evaluation of a staggered three-layer DOI PET detector using a 1 mm LYSO pitch with PETsys TOFPET2 ASIC: comparison of HAMAMATSU and KETEK SiPMs. Phys Med Biol 2021; 66. [PMID: 33906179 DOI: 10.1088/1361-6560/abfbf3] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Accepted: 04/27/2021] [Indexed: 11/11/2022]
Abstract
In this study, we propose a staggered three-layer depth-of-interaction (DOI) detector with a 1 mm crystal pitch and 19.8 mm total crystal thickness for a high-resolution and high-sensitivity small animal in-beam PET scanner. A three-layered stacked LYSO scintillation array (0.9 × 0.9 × 6.6 mm3crystals, 23 × 22 mm2surface area) read out by a SiPM array (8 × 8 channels, 3 × 3 mm2active area/channel and 50μm microcell size) with data acquisition, signal processing and digitization performed using the PETsys Electronics Evaluations kit (based on the TOFPET v2c ASIC) builds a DOI LYSO detector block. The performance of the DOI detector was evaluated in terms of crystal resolvability, energy resolution, and coincidence resolving time (CRT). A comparative performance evaluation of the staggered three-layer LYSO block was conducted with two different SiPM arrays from KETEK and HAMAMATSU. 100% (KETEK) and 99.8% (HAMAMATSU) of the crystals were identified, by using a flood irradiation the front- and back-side. The average energy resolutions for the 1st, 2nd, and 3rd layers were 16.5 (±2.3)%, 20.9(±4.0)%, and 32.7 (±21.0)% (KETEK) and 19.3 (±3.5)%, 21.2 (±4.1)%, and 26.6 (±10.3)% (HAMAMATSU) for the used SiPM arrays. The measured CRTs (FWHM) for the 1st, 2nd, and 3rd layers were 532 (±111) ps, 463 (±108) ps, and 447 (±111) ps (KETEK) and 402 (±46) ps, 392 (±54) ps, and 408 (±196) ps (HAMAMATSU). In conclusion, the performance of the staggered three-layer DOI detector with 1 mm LYSO pitch and 19.8 mm total crystal thickness was fully characterized. The feasibility of a highly performing readout of a high resolution DOI PET detector via SiPM arrays from KETEK and HAMAMATSU employing the PETsys TOFPET v2c ASIC could be demonstrated.
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Affiliation(s)
- Tim Binder
- Ludwig-Maximilians-Universität, Munich, Germany.,KETEK GmbH, Munich, Germany
| | - Han Gyu Kang
- Institute for Quantum Medical Science, National Institutes for Quantum and Radiological Science and Technology (QST), Chiba, Japan
| | | | | | - Taiga Yamaya
- Institute for Quantum Medical Science, National Institutes for Quantum and Radiological Science and Technology (QST), Chiba, Japan
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41
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Lee MS, Cates JW, Gonzalez-Montoro A, Levin CS. High-resolution time-of-flight PET detector with 100 ps coincidence time resolution using a side-coupled phoswich configuration. Phys Med Biol 2021; 66. [PMID: 34106089 DOI: 10.1088/1361-6560/ac01b5] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2020] [Accepted: 05/14/2021] [Indexed: 12/23/2022]
Abstract
Photon time-of-flight (TOF) capability in positron emission tomography (PET) enables reconstructed image signal-to-noise ratio (SNR) improvement. With the coincidence time resolution (CTR) of 100 picosecond (ps), a five-fold SNR improvement can be achieved with a 40 cm diameter imaging subject, relative to a system without TOF capability. This 100 ps CTR can be achieved for aclinically relevantdetector design (crystal element length ≥20 mm with reasonably high crystal packing fraction) using a side-readout PET detector configuration that enables 511 keV photon interaction depth-independent light collection efficiency and lower variance in scintillation photon transit time to the silicon photomultiplier (SiPM). In this study, we propose a new concept of TOF-PET detector to achieve high (<2 mm) resolution, using a 'side-coupled phoswich' configuration, where two crystals with different decay times (τd) are coupled in a side-readout configuration to a common row of photosensors. The proposed design was validated and optimized with GATE Monte Carlo simulation studies to determine an efficient detector design. Based on the simulation results, a proof-of-concept side-coupled phoswich detector design was developed comprising two LSO crystals with the size of 1.9 × 1.9 × 10 mm3with decay times of 34.39 and 43.07 ns, respectively. The phoswich crystals were side-coupled to the same three 4 × 4 mm2SiPMs and detector performances were evaluated. As a result of the experimental evaluation, the side-coupled phoswich configuration achieved CTR of 107 ± 3 ps, energy resolution of 10.5% ± 1.21% at 511 keV and >95% accuracy in identifying interactions in the two adjacent 1.9 × 1.9 × 10 mm3crystal elements using the time-over-threshold technique. Based on our results, we can achieve excellent spatial and energy resolution in addition to ∼100 ps CTR with this novel detector design.
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Affiliation(s)
- Min Sun Lee
- Department of Radiology, Molecular Imaging Program at Stanford, School of Medicine, Stanford University, CA, United States of America.,Nuclear Emergency & Environmental Protection Division, Korea Atomic Energy Research Institute, Daejeon, Republic of Korea
| | - Joshua W Cates
- Applied Nuclear Physics Program, Lawrence Berkeley National Laboratory, CA, United States of America
| | - Andrea Gonzalez-Montoro
- Department of Radiology, Molecular Imaging Program at Stanford, School of Medicine, Stanford University, CA, United States of America
| | - Craig S Levin
- Department of Radiology, Molecular Imaging Program at Stanford, School of Medicine, Stanford University, CA, United States of America.,Department of Physics, Stanford University, CA, United States of America.,Department of Electrical Engineering, Stanford University, CA, United States of America.,Department of Bioengineering, Stanford University, CA, United States of America
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42
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Sarrut D, Bała M, Bardiès M, Bert J, Chauvin M, Chatzipapas K, Dupont M, Etxebeste A, M Fanchon L, Jan S, Kayal G, S Kirov A, Kowalski P, Krzemien W, Labour J, Lenz M, Loudos G, Mehadji B, Ménard L, Morel C, Papadimitroulas P, Rafecas M, Salvadori J, Seiter D, Stockhoff M, Testa E, Trigila C, Pietrzyk U, Vandenberghe S, Verdier MA, Visvikis D, Ziemons K, Zvolský M, Roncali E. Advanced Monte Carlo simulations of emission tomography imaging systems with GATE. Phys Med Biol 2021; 66:10.1088/1361-6560/abf276. [PMID: 33770774 PMCID: PMC10549966 DOI: 10.1088/1361-6560/abf276] [Citation(s) in RCA: 49] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Accepted: 03/26/2021] [Indexed: 12/13/2022]
Abstract
Built on top of the Geant4 toolkit, GATE is collaboratively developed for more than 15 years to design Monte Carlo simulations of nuclear-based imaging systems. It is, in particular, used by researchers and industrials to design, optimize, understand and create innovative emission tomography systems. In this paper, we reviewed the recent developments that have been proposed to simulate modern detectors and provide a comprehensive report on imaging systems that have been simulated and evaluated in GATE. Additionally, some methodological developments that are not specific for imaging but that can improve detector modeling and provide computation time gains, such as Variance Reduction Techniques and Artificial Intelligence integration, are described and discussed.
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Affiliation(s)
- David Sarrut
- Université de Lyon, CREATIS, CNRS UMR5220, Inserm U1294, INSA-Lyon, Université Lyon 1, Lyon, France
| | | | - Manuel Bardiès
- Cancer Research Institute of Montpellier, U1194 INSERM/ICM/Montpellier University, 208 Av des Apothicaires, F-34298 Montpellier cedex 5, France
| | - Julien Bert
- LaTIM, INSERM UMR 1101, IBRBS, Faculty of Medicine, Univ Brest, 22 avenue Camille Desmoulins, F-29238, Brest, France
| | - Maxime Chauvin
- CRCT, UMR 1037, INSERM, Université Toulouse III Paul Sabatier, Toulouse, France
| | | | | | - Ane Etxebeste
- Université de Lyon, CREATIS, CNRS UMR5220, Inserm U1294, INSA-Lyon, Université Lyon 1, Lyon, France
| | - Louise M Fanchon
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY, 10065, United States of America
| | - Sébastien Jan
- Université Paris-Saclay, CEA, CNRS, Inserm, BioMaps, Service Hospitalier Frédéric Joliot, F-91401, Orsay, France
| | - Gunjan Kayal
- CRCT, UMR 1037, INSERM, Université Toulouse III Paul Sabatier, Toulouse, France
- SCK CEN, Belgian Nuclear Research Centre, Boeretang 200, Mol 2400, Belgium
| | - Assen S Kirov
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY, 10065, United States of America
| | - Paweł Kowalski
- High Energy Physics Division, National Centre for Nuclear Research, Otwock-Świerk, Poland
| | - Wojciech Krzemien
- High Energy Physics Division, National Centre for Nuclear Research, Otwock-Świerk, Poland
| | - Joey Labour
- Université de Lyon, CREATIS, CNRS UMR5220, Inserm U1294, INSA-Lyon, Université Lyon 1, Lyon, France
| | - Mirjam Lenz
- FH Aachen University of Applied Sciences, Forschungszentrum Jülich, Jülich, Germany
- Faculty of Mathematics and Natural Sciences, University of Wuppertal, Wuppertal, Germany
| | - George Loudos
- Bioemission Technology Solutions (BIOEMTECH), Alexandras Av. 116, Athens, Greece
| | | | - Laurent Ménard
- Université Paris-Saclay, CNRS/IN2P3, IJCLab, F-91405 Orsay, France
- Université de Paris, IJCLab, F-91405 Orsay France
| | | | | | - Magdalena Rafecas
- Institute of Medical Engineering, University of Lübeck, Lübeck, Germany
| | - Julien Salvadori
- Department of Nuclear Medicine and Nancyclotep molecular imaging platform, CHRU-Nancy, Université de Lorraine, F-54000, Nancy, France
| | - Daniel Seiter
- Department of Medical Physics, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI, 53705, United States of America
| | - Mariele Stockhoff
- Medical Image and Signal Processing (MEDISIP), Ghent University, Ghent, Belgium
| | - Etienne Testa
- Univ. Lyon, Univ. Claude Bernard Lyon 1, CNRS/IN2P3, IP2I Lyon, F-69622, Villeurbanne, France
| | - Carlotta Trigila
- Department of Biomedical Engineering, University of California, Davis, CA 95616 United States of America
| | - Uwe Pietrzyk
- Faculty of Mathematics and Natural Sciences, University of Wuppertal, Wuppertal, Germany
| | | | - Marc-Antoine Verdier
- Université Paris-Saclay, CNRS/IN2P3, IJCLab, F-91405 Orsay, France
- Université de Paris, IJCLab, F-91405 Orsay France
| | - Dimitris Visvikis
- LaTIM, INSERM UMR 1101, IBRBS, Faculty of Medicine, Univ Brest, 22 avenue Camille Desmoulins, F-29238, Brest, France
| | - Karl Ziemons
- FH Aachen University of Applied Sciences, Forschungszentrum Jülich, Jülich, Germany
| | - Milan Zvolský
- Institute of Medical Engineering, University of Lübeck, Lübeck, Germany
| | - Emilie Roncali
- Department of Biomedical Engineering, University of California, Davis, CA 95616 United States of America
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43
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Kim JS, Park CR, Yoon SH, Lee JA, Kim TY, Yang HJ. Improvement of image quality using amplitude-based respiratory gating in PET-computed tomography scanning. Nucl Med Commun 2021; 42:553-565. [PMID: 33625179 DOI: 10.1097/mnm.0000000000001368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
OBJECTIVES This study sought to provide data supporting the expanded clinical use of respiratory gating by assessing the diagnostic accuracy of breathing motion correction using amplitude-based respiratory gating. METHODS A respiratory movement tracking device was attached to a PET-computed tomography scanner, and images were obtained in respiratory gating mode using a motion phantom that was capable of sensing vertical motion. Specifically, after setting amplitude changes and intervals according to the movement cycle using a total of nine combinations of three waveforms and three amplitude ranges, respiratory motion-corrected images were reconstructed using the filtered back projection method. After defining areas of interest in the acquired images in the same image planes, statistical analyses were performed to compare differences in standardized uptake value (SUV), lesion volume, full width at half maximum (FWHM), signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR). RESULTS SUVmax increased by 89.9%, and lesion volume decreased by 27.9%. Full width at half maximum decreased by 53.9%, signal-to-noise ratio increased by 11% and contrast-to-noise ratio increased by 16.3%. Optimal results were obtained when using a rest waveform and 35% duty cycle, in which the change in amplitude in the respiratory phase signal was low, and a constant level of long breaths was maintained. CONCLUSIONS These results demonstrate that respiratory-gated PET-CT imaging can be used to accurately correct for SUV changes and image distortion caused by respiratory motion, thereby providing excellent imaging information and quality.
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Affiliation(s)
- Jung-Soo Kim
- Department of Radiological Technology, Dongnam Health University, Suwon
- Department of Biomedical Science, The Korea University, Sejong
| | - Chan-Rok Park
- Department of Biomedical Science, The Korea University, Sejong
- Department of Nuclear Medicine, Seoul National University Hospital, Seoul
| | - Seok-Hwan Yoon
- Department of Biomedical Science, The Korea University, Sejong
- Department of Nuclear Medicine, Seoul National University Hospital, Seoul
| | - Joo-Ah Lee
- Department of Biomedical Science, The Korea University, Sejong
- Department of Radiation Oncology, Catholic University Incheon St. Mary's Hospital, Incheon
| | - Tae-Yoon Kim
- Department of Radiation Oncology, Catholic University Incheon St. Mary's Hospital, Incheon
- Department of Radiation Oncology, National Cancer Center, Goyang
| | - Hyung-Jin Yang
- Department of Radiation Oncology, Catholic University Incheon St. Mary's Hospital, Incheon
- Department of Physics, The Korea University, Sejong, Korea
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Loignon-Houle F, Gundacker S, Toussaint M, Camirand Lemyre F, Auffray E, Fontaine R, Charlebois SA, Lecoq P, Lecomte R. DOI estimation through signal arrival time distribution: a theoretical description including proof of concept measurements. Phys Med Biol 2021; 66. [PMID: 33831858 DOI: 10.1088/1361-6560/abf604] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2020] [Accepted: 04/08/2021] [Indexed: 11/12/2022]
Abstract
The challenge to reach 10 ps coincidence time resolution (CTR) in time-of-flight positron emission tomography (TOF-PET) is triggering major efforts worldwide, but timing improvements of scintillation detectors will remain elusive without depth-of-interaction (DOI) correction in long crystals. Nonetheless, this momentum opportunely brings up the prospect of a fully time-based DOI estimation since fast timing signals intrinsically carry DOI information, even with a traditional single-ended readout. Consequently, extracting features of the detected signal time distribution could uncover the spatial origin of the interaction and in return, provide enhancement on the timing precision of detectors. We demonstrate the validity of a time-based DOI estimation concept in two steps. First, experimental measurements were carried out with current LSO:Ce:Ca crystals coupled to FBK NUV-HD SiPMs read out by fast high-frequency electronics to provide new evidence of a distinct DOI effect on CTR not observable before with slower electronics. Using this detector, a DOI discrimination using a double-threshold scheme on the analog timing signal together with the signal intensity information was also developed without any complex readout or detector modification. As a second step, we explored by simulation the anticipated performance requirements of future detectors to efficiently estimate the DOI and we proposed four estimators that exploit either more generic or more precise features of the DOI-dependent timestamp distribution. A simple estimator using the time difference between two timestamps provided enhanced CTR. Additional improvements were achieved with estimators using multiple timestamps (e.g. kernel density estimation and neural network) converging to the Cramér-Rao lower bound developed in this work for a time-based DOI estimation. This two-step study provides insights on current and future possibilities in exploiting the timing signal features for DOI estimation aiming at ultra-fast CTR while maintaining detection efficiency for TOF PET.
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Affiliation(s)
- Francis Loignon-Houle
- Sherbrooke Molecular Imaging Center, CRCHUS, and Department of Nuclear Medicine and Radiobiology, Université de Sherbrooke, Sherbrooke, Canada
| | - Stefan Gundacker
- CERN, 1211 Geneva 23, Switzerland.,UniMIB, Piazza dell'Ateneo Nuovo, I-120126, Milano, Italy
| | - Maxime Toussaint
- Department of Computer Science, Université de Sherbrooke, Sherbrooke, Canada
| | | | | | - Réjean Fontaine
- Interdisciplinary Institute for Technological Innovation and Department of Electrical and Computer Engineering, Université de Sherbrooke, Sherbrooke, Canada
| | - Serge A Charlebois
- Interdisciplinary Institute for Technological Innovation and Department of Electrical and Computer Engineering, Université de Sherbrooke, Sherbrooke, Canada
| | - Paul Lecoq
- CERN, 1211 Geneva 23, Switzerland.,Polytechnic University, I3M laboratory, Valencia, Spain
| | - Roger Lecomte
- Sherbrooke Molecular Imaging Center, CRCHUS, and Department of Nuclear Medicine and Radiobiology, Université de Sherbrooke, Sherbrooke, Canada
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45
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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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46
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Ota R. Photon counting detectors and their applications ranging from particle physics experiments to environmental radiation monitoring and medical imaging. Radiol Phys Technol 2021; 14:134-148. [PMID: 33742329 DOI: 10.1007/s12194-021-00615-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 03/09/2021] [Accepted: 03/11/2021] [Indexed: 01/01/2023]
Abstract
Photomultiplier tubes (PMTs) and silicon photomultipliers (SiPMs) have played essential roles in various applications, such as fundamental particle physics experiments, nuclear medicine, and environmental radiation monitoring, for several decades. Understandings their physical properties as well as present applications is indispensable for the development and future applications of these detectors. In this review, we describe the physical principles of PMTs and SiPMs and introduce various applications of these detectors.
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Affiliation(s)
- Ryosuke Ota
- Central Research Laboratory, Hamamatsu Photonics K. K, Hamamatsu, Japan. .,, 5000, Hirakuchi, Hamakita-ku, Hamamatsu, 434-8601, Japan.
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47
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Mannheim JG, Cheng JCK, Vafai N, Shahinfard E, English C, McKenzie J, Zhang J, Barlow L, Sossi V. Cross-validation study between the HRRT and the PET component of the SIGNA PET/MRI system with focus on neuroimaging. EJNMMI Phys 2021; 8:20. [PMID: 33635449 PMCID: PMC7910400 DOI: 10.1186/s40658-020-00349-0] [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: 06/10/2020] [Accepted: 12/16/2020] [Indexed: 01/20/2023] Open
Abstract
Background The Siemens high-resolution research tomograph (HRRT - a dedicated brain PET scanner) is to this day one of the highest resolution PET scanners; thus, it can serve as useful benchmark when evaluating performance of newer scanners. Here, we report results from a cross-validation study between the HRRT and the whole-body GE SIGNA PET/MR focusing on brain imaging. Phantom data were acquired to determine recovery coefficients (RCs), % background variability (%BG), and image voxel noise (%). Cross-validation studies were performed with six healthy volunteers using [11C]DTBZ, [11C]raclopride, and [18F]FDG. Line profiles, regional time-activity curves, regional non-displaceable binding potentials (BPND) for [11C]DTBZ and [11C]raclopride scans, and radioactivity ratios for [18F]FDG scans were calculated and compared between the HRRT and the SIGNA PET/MR. Results Phantom data showed that the PET/MR images reconstructed with an ordered subset expectation maximization (OSEM) algorithm with time-of-flight (TOF) and TOF + point spread function (PSF) + filter revealed similar RCs for the hot spheres compared to those obtained on the HRRT reconstructed with an ordinary Poisson-OSEM algorithm with PSF and PSF + filter. The PET/MR TOF + PSF reconstruction revealed the highest RCs for all hot spheres. Image voxel noise of the PET/MR system was significantly lower. Line profiles revealed excellent spatial agreement between the two systems. BPND values revealed variability of less than 10% for the [11C]DTBZ scans and 19% for [11C]raclopride (based on one subject only). Mean [18F]FDG ratios to pons showed less than 12% differences. Conclusions These results demonstrated comparable performances of the two systems in terms of RCs with lower voxel-level noise (%) present in the PET/MR system. Comparison of in vivo human data confirmed the comparability of the two systems. The whole-body GE SIGNA PET/MR system is well suited for high-resolution brain imaging as no significant performance degradation was found compared to that of the reference standard HRRT.
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Affiliation(s)
- Julia G Mannheim
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada. .,Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard-Karls University Tuebingen, Tuebingen, Germany. .,Cluster of Excellence iFIT (EXC 2180) "Image Guided and Functionally Instructed Tumor Therapies", University of Tuebingen, Tuebingen, Germany.
| | - Ju-Chieh Kevin Cheng
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada.,Pacific Parkinson's Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
| | - Nasim Vafai
- Pacific Parkinson's Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
| | - Elham Shahinfard
- Pacific Parkinson's Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
| | - Carolyn English
- Pacific Parkinson's Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
| | - Jessamyn McKenzie
- Djavad Mowafaghian Centre for Brain Health, Pacific Parkinson's Research Centre, University of British Columbia & Vancouver Coastal Health, Vancouver, British Columbia, Canada
| | - Jing Zhang
- Global MR Applications & Workflow, GE Healthcare Canada, Vancouver, British Columbia, Canada
| | - Laura Barlow
- UBC MRI Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
| | - Vesna Sossi
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada
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48
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Kersting D, Jentzen W, Sraieb M, Costa PF, Conti M, Umutlu L, Antoch G, Nader M, Herrmann K, Fendler WP, Rischpler C, Weber M. Comparing lesion detection efficacy and image quality across different PET system generations to optimize the iodine-124 PET protocol for recurrent thyroid cancer. EJNMMI Phys 2021; 8:14. [PMID: 33587222 PMCID: PMC7884562 DOI: 10.1186/s40658-021-00361-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 01/28/2021] [Indexed: 12/13/2022] Open
Abstract
Background In recurrent differentiated thyroid cancer patients, detectability in 124I PET is limited for lesions with low radioiodine uptake. We assess the improvements in lesion detectability and image quality between three generations of PET scanners with different detector technologies. The results are used to suggest an optimized protocol. Methods Datasets of 10 patients with low increasing thyroglobulin or thyroglobulin antibody levels after total thyroidectomy and radioiodine therapies were included. PET data were acquired and reconstructed on a Biograph mCT PET/CT (whole-body, 4-min acquisition time per bed position; OSEM, OSEM-TOF, OSEM-TOF+PSF), a non-TOF Biograph mMR PET/MR (neck region, 4 min and 20 min; OSEM), and a new generation Biograph Vision PET/CT (whole-body, 4 min; OSEM, OSEM-TOF, OSEM-TOF+PSF). The 20-min image on the mMR was used as reference to calculate the detection efficacy in the neck region. Image quality was rated on a 5-point scale. Results All detected lesions were in the neck region. Detection efficacy was 8/9 (Vision OSEM-TOF and OSEM-TOF+PSF), 4/9 (Vision OSEM), 3/9 (mMR OSEM and mCT OSEM-TOF+PSF), and 2/9 (mCT OSEM and OSEM-TOF). Median image quality was 4 (Vision OSEM-TOF and OSEM-TOF+PSF), 3 (Vision OSEM, mCT OSEM-TOF+PSF, and mMR OSEM 20-min), 2 (mCT OSEM-TOF), 1.5 (mCT OSEM), and 1 (mMR OSEM 4 min). Conclusion At a clinical standard acquisition time of 4 min per bed position, the new generation Biograph Vision using a TOF-based image reconstruction demonstrated the highest detectability and image quality and should, if available, be preferably used for imaging of low-uptake lesions. A prolonged acquisition time for the mostly affected neck region can be useful. Supplementary Information The online version contains supplementary material available at 10.1186/s40658-021-00361-y.
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Affiliation(s)
- David Kersting
- Department of Nuclear Medicine, University Hospital Essen, University of Duisburg-Essen, Hufelandstrasse 55, 45147, Essen, Germany. .,West German Cancer Center (WTZ), Essen, Germany. .,German Cancer Consortium (DKTK), Essen and Dusseldorf, Germany.
| | - Walter Jentzen
- Department of Nuclear Medicine, University Hospital Essen, University of Duisburg-Essen, Hufelandstrasse 55, 45147, Essen, Germany.,West German Cancer Center (WTZ), Essen, Germany.,German Cancer Consortium (DKTK), Essen and Dusseldorf, Germany
| | - Miriam Sraieb
- Department of Nuclear Medicine, University Hospital Essen, University of Duisburg-Essen, Hufelandstrasse 55, 45147, Essen, Germany.,West German Cancer Center (WTZ), Essen, Germany.,German Cancer Consortium (DKTK), Essen and Dusseldorf, Germany
| | - Pedro Fragoso Costa
- Department of Nuclear Medicine, University Hospital Essen, University of Duisburg-Essen, Hufelandstrasse 55, 45147, Essen, Germany.,West German Cancer Center (WTZ), Essen, Germany.,German Cancer Consortium (DKTK), Essen and Dusseldorf, Germany
| | | | - Lale Umutlu
- West German Cancer Center (WTZ), Essen, Germany.,German Cancer Consortium (DKTK), Essen and Dusseldorf, Germany.,Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, 45147, Essen, Germany
| | - Gerald Antoch
- German Cancer Consortium (DKTK), Essen and Dusseldorf, Germany.,Medical Faculty, Department of Diagnostic and Interventional Radiology, University Dusseldorf, 40225, Dusseldorf, Germany
| | - Michael Nader
- Department of Nuclear Medicine, University Hospital Essen, University of Duisburg-Essen, Hufelandstrasse 55, 45147, Essen, Germany.,West German Cancer Center (WTZ), Essen, Germany.,German Cancer Consortium (DKTK), Essen and Dusseldorf, Germany
| | - Ken Herrmann
- Department of Nuclear Medicine, University Hospital Essen, University of Duisburg-Essen, Hufelandstrasse 55, 45147, Essen, Germany.,West German Cancer Center (WTZ), Essen, Germany.,German Cancer Consortium (DKTK), Essen and Dusseldorf, Germany
| | - Wolfgang Peter Fendler
- Department of Nuclear Medicine, University Hospital Essen, University of Duisburg-Essen, Hufelandstrasse 55, 45147, Essen, Germany.,West German Cancer Center (WTZ), Essen, Germany.,German Cancer Consortium (DKTK), Essen and Dusseldorf, Germany
| | - Christoph Rischpler
- Department of Nuclear Medicine, University Hospital Essen, University of Duisburg-Essen, Hufelandstrasse 55, 45147, Essen, Germany.,West German Cancer Center (WTZ), Essen, Germany.,German Cancer Consortium (DKTK), Essen and Dusseldorf, Germany
| | - Manuel Weber
- Department of Nuclear Medicine, University Hospital Essen, University of Duisburg-Essen, Hufelandstrasse 55, 45147, Essen, Germany.,West German Cancer Center (WTZ), Essen, Germany.,German Cancer Consortium (DKTK), Essen and Dusseldorf, Germany
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Hornnes C, Loft A, Højgaard L, Andersen FL. The effect of reduced scan time on response assessment FDG-PET/CT imaging using Deauville score in patients with lymphoma. Eur J Hybrid Imaging 2021; 5:2. [PMID: 34181115 PMCID: PMC8218124 DOI: 10.1186/s41824-021-00096-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 01/03/2021] [Indexed: 12/24/2022] Open
Abstract
PURPOSE [18F]Fluoro-deoxy-glucose positron emission tomography/computed tomography (FDG-PET/CT) is used for response assessment during therapy in Hodgkin lymphoma (HL) and non-Hodgkin lymphoma (NHL). Clinicians report the scans visually using Deauville criteria. Improved performance in modern PET/CT scanners could allow for a reduction in scan time without compromising diagnostic image quality. Additionally, patient throughput can be increased with increasing cost-effectiveness. We investigated the effects of reducing scan time of response assessment FDG-PET/CT in HL and NHL patients on Deauville score (DS) and image quality. METHODS Twenty patients diagnosed with HL/NHL referred to a response assessment FDG-PET/CT were included. PET scans were performed in list-mode with an acquisition time of 120 s per bed position(s/bp). From PET list-mode data images with full acquisition time of 120 s/bp and shorter acquisition times (90, 60, 45, and 30 s/bp) were reconstructed. All images were assessed by two specialists and assigned a DS. We estimated the possible savings when reducing scan time using a simplified model based on assumed values/costs for our hospital. RESULTS There were no significant changes in the visually assessed DS when reducing scan time to 90 s/bp, 60 s/bp, 45 s/bp, and 30 s/bp. Image quality of 90 s/bp images were rated equal to 120 s/bp images. Coefficient of variance values for 120 s/bp and 90 s/bp images was significantly < 15%. The estimated annual savings to the hospital when reducing scan time was 8000-16,000 €/scanner. CONCLUSION Acquisition time can be reduced to 90 s/bp in response assessment FDG-PET/CT without compromising Deauville score or image quality. Reducing acquisition time can reduce costs to the clinic.
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Affiliation(s)
- Charlotte Hornnes
- Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, University of Copenhagen, Blegdamsvej 9, DK-2100, Copenhagen, Denmark
| | - Annika Loft
- Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, University of Copenhagen, Blegdamsvej 9, DK-2100, Copenhagen, Denmark
| | - Liselotte Højgaard
- Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, University of Copenhagen, Blegdamsvej 9, DK-2100, Copenhagen, Denmark
| | - Flemming Littrup Andersen
- Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, University of Copenhagen, Blegdamsvej 9, DK-2100, Copenhagen, Denmark.
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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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