The Experts below are selected from a list of 5376 Experts worldwide ranked by ideXlab platform
Craig S Levin - One of the best experts on this subject based on the ideXlab platform.
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time over threshold for pulse shape discrimination in a time of flight phoswich pet detector
Physics in Medicine and Biology, 2017Co-Authors: Chenming Chang, Joshua W Cates, Craig S LevinAbstract:It is well known that a PET detector capable of measuring both photon time-of-flight (TOF) and depth-of-interaction (DOI) improves the image quality and accuracy. Phoswich designs have been realized in PET detectors to measure DOI for more than a decade. However, PET detectors based on phoswich designs put great demand on the readout circuits, which have to differentiate the pulse shape produced by different Crystal layers. A simple pulse shape discrimination approach is required to realize the phoswich designs in a clinical PET scanner, which consists of thousands of Scintillation Crystal elements. In this work, we studied time-over-threshold (ToT) as a pulse shape parameter for DOI. The energy, timing and DOI performance were evaluated for a phoswich detector design comprising mm LYSO:Ce Crystal optically coupled to mm calcium co-doped LSO:Ce,Ca(0.4%) Crystal read out by a silicon photomultiplier (SiPM). A DOI accuracy of 97.2% has been achieved for photopeak events using the proposed time-over-threshold (ToT) processing. The energy resolution without correction for SiPM non-linearity was % and % FWHM at 511 keV for LYSO and LSO Crystal layers, respectively. The coincidence time resolution for photopeak events ranges from 164.6 ps to 183.1 ps FWHM, depending on the layer combinations. The coincidence time resolution for inter-Crystal scatter events ranges from 214.6 ps to 418.3 ps FWHM, depending on the energy windows applied. These results show great promises of using ToT for pulse shape discrimination in a TOF phoswich detector since a ToT measurement can be easily implemented in readout electronics.
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advances in coincidence time resolution for pet
Physics in Medicine and Biology, 2016Co-Authors: Joshua W Cates, Craig S LevinAbstract:Coincidence time resolution (CTR), an important parameter for time-of-flight (TOF) PET performance, is determined mainly by properties of the Scintillation Crystal and photodetector used. Stable production techniques for LGSO:Ce (Lu1.8Gd0.2SiO5:Ce) with decay times varying from ∼ 30-40 ns have been established over the past decade, and the decay time can be accurately controlled with varying cerium concentration (0.025-0.075 mol%). This material is promising for TOF-PET, as it has similar light output and equivalent stopping power for 511 keV annihilation photons compared to industry standard LSO:Ce and LYSO:Ce, and the decay time is improved by more than 30% with proper Ce concentration. This work investigates the achievable CTR with LGSO:Ce (0.025 mol%) when coupled to new silicon photomultipliers. Crystal element dimension is another important parameter for achieving fast timing. 20 mm length Crystal elements achieve higher 511 keV photon detection efficiency, but also introduce higher Scintillation photon transit time variance. 3 mm length Crystals are not practical for PET, but have reduced Scintillation transit time spread. The CTR between pairs of 2.9 × 2.9 × 3 mm(3) and 2.9 × 2.9 × 20 mm(3) LGSO:Ce Crystals was measured to be 80 ± 4 and 122 ± 4 ps FWHM, respectively. Measurements of light yield and intrinsic decay time are also presented for a thorough investigation into the timing performance with LGSO:Ce (0.025 mol%).
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electrical delay line multiplexing for pulsed mode radiation detectors
Physics in Medicine and Biology, 2015Co-Authors: Ruud Vinke, Jung Yeol Yeom, Craig S LevinAbstract:Medical imaging systems are composed of a large number of position sensitive radiation detectors to provide high resolution imaging. For example, whole-body Positron Emission Tomography (PET) systems are typically composed of thousands of Scintillation Crystal elements, which are coupled to photosensors. Thus, PET systems greatly benefit from methods to reduce the number of data acquisition channels, in order to reduce the system development cost and complexity. In this paper we present an electrical delay line multiplexing scheme that can significantly reduce the number of readout channels, while preserving the signal integrity required for good time resolution performance. We experimented with two 4 × 4 LYSO Crystal arrays, with Crystal elements having 3 mm × 3 mm × 5 mm and 3 mm × 3 mm × 20 mm dimensions, coupled to 16 Hamamatsu MPPC S10931-050P SiPM elements. Results show that each Crystal could be accurately identified, even in the presence of Scintillation light sharing and inter-Crystal Compton scatter among neighboring Crystal elements. The multiplexing configuration degraded the coincidence timing resolution from ∼243 ps FWHM to ∼272 ps FWHM when 16 SiPM signals were combined into a single channel for the 4 × 4 LYSO Crystal array with 3 mm × 3 mm × 20 mm Crystal element dimensions, in coincidence with a 3 mm × 3 mm × 5 mm LYSO Crystal pixel. The method is flexible to allow multiplexing configurations across different block detectors, and is scalable to an entire ring of detectors.
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electrical delay line multiplexing for pulsed mode radiation detectors
Nuclear Science Symposium and Medical Imaging Conference, 2013Co-Authors: Ruud Vinke, Jung Yeol Yeom, Craig S LevinAbstract:Medical imaging systems are often composed of a large number of radiation detectors to provide high resolution imaging. For example, whole-body Positron Emission Tomography (PET) systems are typically composed of thousands of Scintillation Crystal elements, which are coupled to photosensors. PET systems would greatly benefit from methods to reduce the number of data acquisition channels, such that the cost and complexity can be kept at a minimum. In this paper we present an electrical delay line multiplexing scheme that can significantly reduce the number of readout channels, while the signal integrity is preserved for good time resolution performance. A 4 × 4 LYSO Crystal array, with each Crystal element having 3 mm × 3 mm × 5 mm dimensions, was coupled to 16 Hamamatsu MPPC S10931-050P SiPM elements. For proof-of-concept, 4 SiPM elements of the array were connected to the multiplexing stage. Results show that each SiPM element could be accurately identified. The method is flexible to allow multiplexing configurations across different block detectors, and is scalable to an entire ring of detectors.
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first performance results of ce gagg Scintillation Crystals with silicon photomultipliers
IEEE Transactions on Nuclear Science, 2013Co-Authors: Jung Yeol Yeom, Seiichi Yamamoto, S E Derenzo, V C Spanoudaki, Kei Kamada, Takanori Endo, Craig S LevinAbstract:A new single-Crystal Cerium doped Gd3Al2Ga3 O123Al2Ga3 O12 (GAGG) Scintillation Crystal with high luminosity, high density and relatively fast decay time has successfully been grown. We report on the first performance results of the new GAGG Scintillation Crystal read out with silicon photomultipliers (SiPM) from Hamamatsu (MPPC) and FBK. The best energy resolution (511 keV peak of Ge-68) of 7.9% was attained with GAGG coupled to MPPC and 9.0% with the FBK SiPM after correcting for non-linearity. On the other hand, the best coincidence resolving time (FWHM) of polished 3 × 3 × 5 mm3 and 3 × 3 × 20mm3Crystals were 464 ±12 ps and 577 ±22 ps for GAGG Crystals compared to 179 ±8 ps and 214 ±6 ps for LYSO Crystals respectively with MPPCs. The rise time of GAGG was measured to be 200 ps (75%) and 6 ns (25%) while the decay time was 140 ns (92%), 500 ns (7.7%) 6000 ns (0.3%).
Michael Schafers - One of the best experts on this subject based on the ideXlab platform.
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performance evaluation of the 32 module quadhidac small animal pet scanner
The Journal of Nuclear Medicine, 2005Co-Authors: Klaus P. Schäfers, Michael Kriens, Otmar Schober, Andrew J. Reader, C. Knoess, Michael SchafersAbstract:UNLABELLED: The 32-module quadHIDAC is a commercial, high-resolution animal PET scanner, based on gas multiwire proportional chambers. METHODS: Several scanner parameters that characterize the performance of the system were evaluated in this study, such as spatial resolution, absolute sensitivity, scatter, and count rate performance. The spatial resolution has been determined with filtered back-projected images of a point source. A line source, a mouse phantom, and a rat phantom have been used to characterize the count rate performance. The scatter fraction and photon absorption have been measured with a mouse scatter phantom. The absolute sensitivity has been determined using a line source with aluminum shields of different thickness. RESULTS: Spatial resolution (full width at half maximum) offers values of 1.08, 1.08, and 1.04 mm in the radial, tangential, and axial directions, respectively. The maximum count rate is 370 kcps for a line source of 19 MBq activity. Registration of scattered coincidences is caused primarily by photons scattering in the large coincidence detectors. For a mouse-sized object, only 5% of the measured coincidences scatter inside the animal, whereas 32% of the coincidences scatter inside the detectors. Photon attenuation within a mouse phantom was 22%. After scatter corrections, the absolute sensitivity of the system is 15.2 cps/kBq for a point source and 13.7 cps/kBq for a 7.8-cm-long line source. The peak noise equivalent count rates are 67 kcps@209 kBq/mL for the mouse phantom and 52 kcps@96 kBq/mL for the rat phantom. Finally, a comparison has been made with the microPET R4, a commercial Scintillation Crystal-based PET camera. CONCLUSION: The results confirm that the quadHIDAC PET scanner, with its large cylindric field of view (165-mm diameter, 280-mm axial length), is particularly suitable for imaging small animals such as mice or rats.
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performance evaluation of the 32 module quadhidac small animal pet scanner
The Journal of Nuclear Medicine, 2005Co-Authors: Klaus P. Schäfers, Michael Kriens, Otmar Schober, Andrew J. Reader, C. Knoess, Michael SchafersAbstract:The 32-module quadHIDAC is a commercial, high-resolution animal PET scanner, based on gas multiwire proportional chambers. Methods: Several scanner parameters that characterize the performance of the system were evaluated in this study, such as spatial resolution, absolute sensitivity, scatter, and count rate performance. The spatial resolution has been determined with filtered back-projected images of a point source. A line source, a mouse phantom, and a rat phantom have been used to characterize the count rate performance. The scatter fraction and photon absorption have been measured with a mouse scatter phantom. The absolute sensitivity has been determined using a line source with aluminum shields of different thickness. Results: Spatial resolution (full width at half maximum) offers values of 1.08, 1.08, and 1.04 mm in the radial, tangential, and axial directions, respectively. The maximum count rate is 370 kcps for a line source of 19 MBq activity. Registration of scattered coincidences is caused primarily by photons scattering in the large coincidence detectors. For a mouse-sized object, only 5% of the measured coincidences scatter inside the animal, whereas 32% of the coincidences scatter inside the detectors. Photon attenuation within a mouse phantom was 22%. After scatter corrections, the absolute sensitivity of the system is 15.2 cps/kBq for a point source and 13.7 cps/kBq for a 7.8-cm-long line source. The peak noise equivalent count rates are 67 kcps@209 kBq/mL for the mouse phantom and 52 kcps@96 kBq/mL for the rat phantom. Finally, a comparison has been made with the microPET R4, a commercial Scintillation Crystal–based PET camera. Conclusion: The results confirm that the quadHIDAC PET scanner, with its large cylindric field of view (165-mm diameter, 280-mm axial length), is particularly suitable for imaging small animals such as mice or rats.
Inadama Naoko - One of the best experts on this subject based on the ideXlab platform.
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DOI detection capability of 3D Crystal array standing over two pmts
2019Co-Authors: Hamamoto Manabu, Inadama Naoko, Murayama Hideo, Yamaya Taiga, Tsuda Tomoaki, Ono YusukeAbstract:Abstract-Absence of Scintillation Crystal in the region between adjacent PMTs, PMT blind region, will cause loss of data sampling and less sensitivity in a PET or another system.We propose design of a depth of interaction (DOI) detector to fill up the PMT blind region with Crystals. In the design, a 3-dimensional (3D) array of single kind Crystals stands over two PMTs. The Crystal array is optically coupled to the PMTs directly and materials between Crystal elements are chosen among optical film, coupling material and just remained as air gap to control Scintillation light path in the Crystal array instead of coupling a light guide on the bottom of the array as is generally done. Not only reflector but translucent film is also utilized as optical film in the DOI detector design. In this paper, first, we seek for an available DOI Crystal array design in simple setting with a PMT, and then we demonstrate its DOI detection capability in the setting with two PMTs. The DOI detector is developed with the intention of the use in jPET-RD system; the PET system we have developed for small animals. In the system, there is about 6 mm interval in axial direction between outer anodes of adjacent two PMTs. The cross section of the Crystal elements is 1.46 mm by 1.46 mm in jPET-RD detector so that 2-layers of four Crystals are involved in the PMT blind region. We introduce the design of the 2-layer DOI Crystal array for the region and the results of its performance evaluationNuclear Science Symposium & Medical Imaging Conferenc
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Application of Scintillation Crystals Cut As A Triangular Prism for A PET Detector
2019Co-Authors: Inadama NaokoAbstract:A depth-of interaction (DOI) PET detector is a detector which provides a detected radiation location 3-dimensionally. The DOI information is important to ensure the PET scanner has both high resolution and high sensitivity. We have successfully developed a 4-layer DOI detector which is composed of four layers of Scintillation Crystal arrays optically coupled to a position sensitive photomultiplier tube. Scintillation light spread in the Crystal arrays is utilized for the Crystal identification in the 4-layer DOI Crystal arrays. As a new trial in our further investigation about Scintillation light spread in a Crystal array, we used Scintillation Crystals cut as a triangular prism (triangular Crystal) with the expectation that the Crystal shape would cause different light behavior compared with rectangular Crystals generally used for a PET detector. As an application of the triangular Crystals, we developed a 3-layer DOI detector with Lu(2x)Gd(2(1-x))SiO(5) (LGSO) Crystals in dimensions of an equilateral triangle of 3.0 mm one side in cross section and 10.0 mm long. The detector performance evaluation showed sufficient Crystal identification performance and energy resolution of 9 - 12% was also obtained.第5回日韓医学物理会
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Four-Layer DOI-PET Detector with a Silicon Photomultiplier Array
2019Co-Authors: Nishikido Fumihiko, Yoshida Eiji, Inadama Naoko, Yamaya Taiga, Shibuya Kengo, Oda Ichiro, Kitamura Keishi, Murayama HideoAbstract:Silicon photomultipliers are promising photo detector for being used in PET detectors due to high internal gain, low power consumption and insensitiveness for magnetic fields. We are developing a PET detector which consists of a Scintillation Crystal array and a silicon photomultiplier array. In addition, the capability of the depth-of-interaction (DOI) is required to high performance PET to reduce the parallax error degrading the uniformity of spatial resolution. We are studying the four-layer DOI PET detector wit a silicon photomultiplier array. The four-layer DOI detector consists of a 6x6x4 LYSO Crystal array and the SPMArray (SPMsrray3035G16, SensL, Ireland) of the array of sixteen silicon photomultiplier detectors (each 3mm x 3mm). The size of each Crystal element is 1.46 mm x 1.46 mm x 4.5 mm. The DOI encoding method was applied the previously presented methods which can identify Crystals of four layers with only one photo detector and Crystal array by the arrangement of the reflector inserted between Crystals. We measured the performance of the four-layer DOI PET detector. Additionally, the related characteristics of SPMArray in the case of being used in the four-layer DOI PET detector were measured. As a result, the Crystal identification was as similar as the detector which consisted of the same Crystal array and the position sensitive photomultiplier tube we typically used. Sufficient energy resolution as a PET detector was obtained. We will present more detail results of the experiment.2008 Nuclear Science Symposium, Medical Imaging Conferenc
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Proposal of a 8-Layer DOI Detector Composed of Same Scintillation Crystal Elements
2019Co-Authors: Inadama NaokoAbstract:Previously, we developed a 4-layer depth of interaction (DOI) detector. It is composed of four layers of a Scintillation Crystal array and a position sensitive photomultiplier tube (PS-PMT) and by removing some reflectors between the Crystal elements in the array, we control Scintillation light distribution on the PS-PMT so that the responses of all Crystal elements are discriminated. We also proposed a 2-layer DOI encoding method by using the Crystal elements cut as a triangular prism and proved its capability. Combining these two methods, here we propose an 8-layer DOI encoding method. The method makes it possible that the 8-layer DOI detector is consisted of same Scintillation Crystal elements, that is to say, any Scintillation Crystals. The method was demonstrated with the Lu2xGd2(1-x)SiO5 (LGSO) Crystals. The obtained results indicated the possibility of the proposed method.2009 Nuclear Science Symposium, Medical Imaging Conferenc
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Development of a DOI-PET detector X\u27tal cube: optimal position calculation for each optical condition in the Scintillation Crystal block
2019Co-Authors: Inadama Naoko, Yoshida Eiji, Murayama Hideo, Nishikido Fumihiko, Hirano Yoshiyuki, Tashima Hideaki, Nitta Munetaka, Ito Hiroshi, Yamaya TaigaAbstract:X\u27tal cube is the PET detector we have developed and it has the capability of getting depth of interaction (DOI) information about radiation detected position in the detector. Fig. 1 illustrates the structure of the X\u27tal cube. It is composed of a Scintillation Crystal block and a number of multi-pixel photon counters (MPPCs) on the Crystal block surfaces. A MPPC is thin and small enough not to interfere in radiation detection. The Crystal block is segmented 3-dimensionally into small cubes. There is no reflector between the Crystal segments so that Scintillation light originating in a radiation detected segment spreads to all 6 surfaces and detected by all MPPCs. Simple Anger-type calculation can be used in position calculation for segment identification. By expressing results of the calculation with the all MPPC signals in a 3-dimensional (3D) position histogram, we get response corresponding to each Crystal segment. In the first stage, we composed of the Crystal block by fabricating a 3D array with small cubic Crystal segments (array-XC). Later, we newly developed the laser processing technique to segment inside of a monolithic Crystal block 3-dimensionally (laser-XC). In both ways, we have already confirmed that small segments such as 1.0 mm x 1.0 mm x 1.0 mm segments can be identified in the X\u27tal cube structure. Meanwhile, in a basic study, we found that Scintillation light spreads in different manners between the array and laser-XCs due to different condition of optical discontinuity between Crystal segments. Because different light distribution among MPPCs should result in different segment response positioning in the 3D position histogram, we reconsidered about the weight of Anger-type calculation to improve segment identification performance for the array and laser- XCs.第105回日本医学物理学会学術大
Yamaya Taiga - One of the best experts on this subject based on the ideXlab platform.
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DOI detection capability of 3D Crystal array standing over two pmts
2019Co-Authors: Hamamoto Manabu, Inadama Naoko, Murayama Hideo, Yamaya Taiga, Tsuda Tomoaki, Ono YusukeAbstract:Abstract-Absence of Scintillation Crystal in the region between adjacent PMTs, PMT blind region, will cause loss of data sampling and less sensitivity in a PET or another system.We propose design of a depth of interaction (DOI) detector to fill up the PMT blind region with Crystals. In the design, a 3-dimensional (3D) array of single kind Crystals stands over two PMTs. The Crystal array is optically coupled to the PMTs directly and materials between Crystal elements are chosen among optical film, coupling material and just remained as air gap to control Scintillation light path in the Crystal array instead of coupling a light guide on the bottom of the array as is generally done. Not only reflector but translucent film is also utilized as optical film in the DOI detector design. In this paper, first, we seek for an available DOI Crystal array design in simple setting with a PMT, and then we demonstrate its DOI detection capability in the setting with two PMTs. The DOI detector is developed with the intention of the use in jPET-RD system; the PET system we have developed for small animals. In the system, there is about 6 mm interval in axial direction between outer anodes of adjacent two PMTs. The cross section of the Crystal elements is 1.46 mm by 1.46 mm in jPET-RD detector so that 2-layers of four Crystals are involved in the PMT blind region. We introduce the design of the 2-layer DOI Crystal array for the region and the results of its performance evaluationNuclear Science Symposium & Medical Imaging Conferenc
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Four-Layer DOI-PET Detector with a Silicon Photomultiplier Array
2019Co-Authors: Nishikido Fumihiko, Yoshida Eiji, Inadama Naoko, Yamaya Taiga, Shibuya Kengo, Oda Ichiro, Kitamura Keishi, Murayama HideoAbstract:Silicon photomultipliers are promising photo detector for being used in PET detectors due to high internal gain, low power consumption and insensitiveness for magnetic fields. We are developing a PET detector which consists of a Scintillation Crystal array and a silicon photomultiplier array. In addition, the capability of the depth-of-interaction (DOI) is required to high performance PET to reduce the parallax error degrading the uniformity of spatial resolution. We are studying the four-layer DOI PET detector wit a silicon photomultiplier array. The four-layer DOI detector consists of a 6x6x4 LYSO Crystal array and the SPMArray (SPMsrray3035G16, SensL, Ireland) of the array of sixteen silicon photomultiplier detectors (each 3mm x 3mm). The size of each Crystal element is 1.46 mm x 1.46 mm x 4.5 mm. The DOI encoding method was applied the previously presented methods which can identify Crystals of four layers with only one photo detector and Crystal array by the arrangement of the reflector inserted between Crystals. We measured the performance of the four-layer DOI PET detector. Additionally, the related characteristics of SPMArray in the case of being used in the four-layer DOI PET detector were measured. As a result, the Crystal identification was as similar as the detector which consisted of the same Crystal array and the position sensitive photomultiplier tube we typically used. Sufficient energy resolution as a PET detector was obtained. We will present more detail results of the experiment.2008 Nuclear Science Symposium, Medical Imaging Conferenc
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Development of a DOI-PET detector X\u27tal cube: optimal position calculation for each optical condition in the Scintillation Crystal block
2019Co-Authors: Inadama Naoko, Yoshida Eiji, Murayama Hideo, Nishikido Fumihiko, Hirano Yoshiyuki, Tashima Hideaki, Nitta Munetaka, Ito Hiroshi, Yamaya TaigaAbstract:X\u27tal cube is the PET detector we have developed and it has the capability of getting depth of interaction (DOI) information about radiation detected position in the detector. Fig. 1 illustrates the structure of the X\u27tal cube. It is composed of a Scintillation Crystal block and a number of multi-pixel photon counters (MPPCs) on the Crystal block surfaces. A MPPC is thin and small enough not to interfere in radiation detection. The Crystal block is segmented 3-dimensionally into small cubes. There is no reflector between the Crystal segments so that Scintillation light originating in a radiation detected segment spreads to all 6 surfaces and detected by all MPPCs. Simple Anger-type calculation can be used in position calculation for segment identification. By expressing results of the calculation with the all MPPC signals in a 3-dimensional (3D) position histogram, we get response corresponding to each Crystal segment. In the first stage, we composed of the Crystal block by fabricating a 3D array with small cubic Crystal segments (array-XC). Later, we newly developed the laser processing technique to segment inside of a monolithic Crystal block 3-dimensionally (laser-XC). In both ways, we have already confirmed that small segments such as 1.0 mm x 1.0 mm x 1.0 mm segments can be identified in the X\u27tal cube structure. Meanwhile, in a basic study, we found that Scintillation light spreads in different manners between the array and laser-XCs due to different condition of optical discontinuity between Crystal segments. Because different light distribution among MPPCs should result in different segment response positioning in the 3D position histogram, we reconsidered about the weight of Anger-type calculation to improve segment identification performance for the array and laser- XCs.第105回日本医学物理学会学術大
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Performance Evaluation of jPET-RD Detector Composed of 32 x 32 x 4 LYSO
2019Co-Authors: Takahashi Kei, Yoshida Eiji, Inadama Naoko, Murayama Hideo, Yamaya Taiga, Tsuda Tomoaki, Nishikido Fumihiko, Shibuya Kengo, Kitamura Keishi, Kawai HideyukiAbstract:jPET-RD (for Rodents with depth of interaction (DOI) detectors) is the small animal PET scanner which is under development at the National Institute of Radiological Sciences in Japan. High sensitivity is expected without degradation of the spatial resolution by the use of four-layer DOI detectors in the scanner. The detector consists of four-layers of Scintillation Crystal array optically coupled to a position sensitive photo-detector and Scintillation light controlled by a proper reflector arrangement in the Crystal array provides information for the Crystal of detection. A basic study such as the validation of the four-layer DOI encoding method and detector parameter optimization has been carried out with a subset of the Crystal arrays; a 10 X 10 X 4 array of Lu2(1-x)Y2xSiO5 (LYSO, x=0.02). We determined detector parameters through the basic study and will compose the full-size detector with a 32 X 32 X 4 LYSO Crystal array. In this paper, we introduce the jPET-RD system, detector design and its performance. The subset of Crystal array in optimal design showed enough Crystal identification performance and 12-17% energy resolutions for all layer Crystals. The results confirm the expectation of the same level performance on the full-size detector.World Congress on Medical Physics and Biomedical Engineering 200
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Basic study of the PET detector
2019Co-Authors: Inadama Naoko, Yoshida Eiji, Murayama Hideo, Nishikido Fumihiko, Tashima Hideaki, Yoshioka Shunsuke, Yamaya TaigaAbstract:The X\u27tal cube is a PET detector we have developed. It has the new structure, which consists of a monolithic Scintillation Crystal block segmented 3-dimensionally into cubes and semiconductor photo-detectors are coupled on all sides of the Crystal block. The Crystal segment originating Scintillation light can be identified by a simple position calculation with the photo-detector signals. Determination of the Crystal segment provides radiation detected location inside the Crystal block including depth of interaction (DOI) information which is necessary for a PET scanner to have both high sensitivity and high spatial resolution. We have already showed sufficient performance of the X\u27tal cube with the prototype using multi-pixel photon counters (MPPCs) for the photo-detectors and a 3-dimensional (3D) array of cubic Crystals for the Crystal block (array-X\u27tal cube). Because we newly succeeded to fabricate the 3D array by applying laser processing to a monolithic Crystal for easy and reliable assembly, in this study, we evaluated performance of the X\u27tal cube using the monolithic Crystal as the Crystal block (laser-X\u27tal cube). The results showed high Crystal identification performance and average energy resolution of 8.6 % for all Crystal segments, which are superior to the array-X\u27tal cube performance.第6回日韓医学物理学術合同大会(JKMP
Klaus P. Schäfers - One of the best experts on this subject based on the ideXlab platform.
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performance evaluation of the 32 module quadhidac small animal pet scanner
The Journal of Nuclear Medicine, 2005Co-Authors: Klaus P. Schäfers, Michael Kriens, Otmar Schober, Andrew J. Reader, C. Knoess, Michael SchafersAbstract:UNLABELLED: The 32-module quadHIDAC is a commercial, high-resolution animal PET scanner, based on gas multiwire proportional chambers. METHODS: Several scanner parameters that characterize the performance of the system were evaluated in this study, such as spatial resolution, absolute sensitivity, scatter, and count rate performance. The spatial resolution has been determined with filtered back-projected images of a point source. A line source, a mouse phantom, and a rat phantom have been used to characterize the count rate performance. The scatter fraction and photon absorption have been measured with a mouse scatter phantom. The absolute sensitivity has been determined using a line source with aluminum shields of different thickness. RESULTS: Spatial resolution (full width at half maximum) offers values of 1.08, 1.08, and 1.04 mm in the radial, tangential, and axial directions, respectively. The maximum count rate is 370 kcps for a line source of 19 MBq activity. Registration of scattered coincidences is caused primarily by photons scattering in the large coincidence detectors. For a mouse-sized object, only 5% of the measured coincidences scatter inside the animal, whereas 32% of the coincidences scatter inside the detectors. Photon attenuation within a mouse phantom was 22%. After scatter corrections, the absolute sensitivity of the system is 15.2 cps/kBq for a point source and 13.7 cps/kBq for a 7.8-cm-long line source. The peak noise equivalent count rates are 67 kcps@209 kBq/mL for the mouse phantom and 52 kcps@96 kBq/mL for the rat phantom. Finally, a comparison has been made with the microPET R4, a commercial Scintillation Crystal-based PET camera. CONCLUSION: The results confirm that the quadHIDAC PET scanner, with its large cylindric field of view (165-mm diameter, 280-mm axial length), is particularly suitable for imaging small animals such as mice or rats.
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performance evaluation of the 32 module quadhidac small animal pet scanner
The Journal of Nuclear Medicine, 2005Co-Authors: Klaus P. Schäfers, Michael Kriens, Otmar Schober, Andrew J. Reader, C. Knoess, Michael SchafersAbstract:The 32-module quadHIDAC is a commercial, high-resolution animal PET scanner, based on gas multiwire proportional chambers. Methods: Several scanner parameters that characterize the performance of the system were evaluated in this study, such as spatial resolution, absolute sensitivity, scatter, and count rate performance. The spatial resolution has been determined with filtered back-projected images of a point source. A line source, a mouse phantom, and a rat phantom have been used to characterize the count rate performance. The scatter fraction and photon absorption have been measured with a mouse scatter phantom. The absolute sensitivity has been determined using a line source with aluminum shields of different thickness. Results: Spatial resolution (full width at half maximum) offers values of 1.08, 1.08, and 1.04 mm in the radial, tangential, and axial directions, respectively. The maximum count rate is 370 kcps for a line source of 19 MBq activity. Registration of scattered coincidences is caused primarily by photons scattering in the large coincidence detectors. For a mouse-sized object, only 5% of the measured coincidences scatter inside the animal, whereas 32% of the coincidences scatter inside the detectors. Photon attenuation within a mouse phantom was 22%. After scatter corrections, the absolute sensitivity of the system is 15.2 cps/kBq for a point source and 13.7 cps/kBq for a 7.8-cm-long line source. The peak noise equivalent count rates are 67 kcps@209 kBq/mL for the mouse phantom and 52 kcps@96 kBq/mL for the rat phantom. Finally, a comparison has been made with the microPET R4, a commercial Scintillation Crystal–based PET camera. Conclusion: The results confirm that the quadHIDAC PET scanner, with its large cylindric field of view (165-mm diameter, 280-mm axial length), is particularly suitable for imaging small animals such as mice or rats.