Pub Date : 2016-10-01DOI: 10.1109/NSSMIC.2016.8069544
D. Grau-Ruíz, J. Rigla, E. Diaz-Caballero, A. Nacev, A. Aguilar, P. Bellido, P. Conde, A. Gonzalez-Montoro, A. González, L. Hernández, A. Iborra, L. Moliner, M. Rodríguez-Álvarez, S. Sánchez, M. Seimetz, A. Soriano, L. Vidal, I. Weinberg, F. Sánchez, J. Benlloch
Magnetic Resonance Imaging (MRI) is a widely used technique to obtain images in different applications based on the nuclear magnetic renonance (NMR) phenomenon. Gradient coils are the responsible components for encoding the volume of interest (VOI). Linearity, inductance and resistance are taken in account to perform the gradient coil design. In this work, EM and thermal gradient coil properties are studied and two cooling system are presented to cool them. Finally, the gradient coils are tested in a biplanar permanent magnet system and a 2D phantom image is obtained.
{"title":"Feasibility study of a gradient coil for a dedicated and portable single-sided MRI system","authors":"D. Grau-Ruíz, J. Rigla, E. Diaz-Caballero, A. Nacev, A. Aguilar, P. Bellido, P. Conde, A. Gonzalez-Montoro, A. González, L. Hernández, A. Iborra, L. Moliner, M. Rodríguez-Álvarez, S. Sánchez, M. Seimetz, A. Soriano, L. Vidal, I. Weinberg, F. Sánchez, J. Benlloch","doi":"10.1109/NSSMIC.2016.8069544","DOIUrl":"https://doi.org/10.1109/NSSMIC.2016.8069544","url":null,"abstract":"Magnetic Resonance Imaging (MRI) is a widely used technique to obtain images in different applications based on the nuclear magnetic renonance (NMR) phenomenon. Gradient coils are the responsible components for encoding the volume of interest (VOI). Linearity, inductance and resistance are taken in account to perform the gradient coil design. In this work, EM and thermal gradient coil properties are studied and two cooling system are presented to cool them. Finally, the gradient coils are tested in a biplanar permanent magnet system and a 2D phantom image is obtained.","PeriodicalId":184587,"journal":{"name":"2016 IEEE Nuclear Science Symposium, Medical Imaging Conference and Room-Temperature Semiconductor Detector Workshop (NSS/MIC/RTSD)","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131278703","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2016-10-01DOI: 10.1109/NSSMIC.2016.8069494
Sen Wang, Li Zhang, Xiaofei Xu, Dufan Wu
The degrading factors of photon counting detectors such as charge-sharing, K-escape, resulting in spectrum distortion, set the crucial limitation for its application in quantitative imaging. We present a method to eliminate the degrading factors by spectral deconvolution. Simulation study and experimental study were carried out to verify its effectiveness and robustness. In simulation study, the method can significantly reduce the bias between detected photon counts and the theoretical value, which implies the effectiveness. Poisson noise was added to test the robustness and we find the result shows no significant difference to noiseless result when up to 106 photons are detected. In experimental study, theoretical spectrum is not easily accessible, instead we verified the effectiveness by calculating the width of an aluminum plate based on Beer-Lambert Law, which is supposed to be consistent among the whole energy range. An improvement can be seen after deconvolution and the output shows a good agreement with simulation result. Furthermore, we simulated a CT reconstruction process using the proposed method and found the reconstructed μ fits the theoretical value very well, which manifests a promising potential in quantitative X-ray spectral imaging.
{"title":"Preliminary study of quantitative X-ray spectral imaging with spectral deconvolution","authors":"Sen Wang, Li Zhang, Xiaofei Xu, Dufan Wu","doi":"10.1109/NSSMIC.2016.8069494","DOIUrl":"https://doi.org/10.1109/NSSMIC.2016.8069494","url":null,"abstract":"The degrading factors of photon counting detectors such as charge-sharing, K-escape, resulting in spectrum distortion, set the crucial limitation for its application in quantitative imaging. We present a method to eliminate the degrading factors by spectral deconvolution. Simulation study and experimental study were carried out to verify its effectiveness and robustness. In simulation study, the method can significantly reduce the bias between detected photon counts and the theoretical value, which implies the effectiveness. Poisson noise was added to test the robustness and we find the result shows no significant difference to noiseless result when up to 106 photons are detected. In experimental study, theoretical spectrum is not easily accessible, instead we verified the effectiveness by calculating the width of an aluminum plate based on Beer-Lambert Law, which is supposed to be consistent among the whole energy range. An improvement can be seen after deconvolution and the output shows a good agreement with simulation result. Furthermore, we simulated a CT reconstruction process using the proposed method and found the reconstructed μ fits the theoretical value very well, which manifests a promising potential in quantitative X-ray spectral imaging.","PeriodicalId":184587,"journal":{"name":"2016 IEEE Nuclear Science Symposium, Medical Imaging Conference and Room-Temperature Semiconductor Detector Workshop (NSS/MIC/RTSD)","volume":"291 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133796056","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2016-10-01DOI: 10.1109/NSSMIC.2016.8069622
Konstantinos A. Mountris, J. Bert, D. Visvikis
Planning the radioactive seeds delivery during prostate brachytherapy is a critical part of the overall procedure. The planning process is time consuming and requires substantial user input and implication to ensure the optimal decision on the seeds' locations. Therefore efforts have been done to help in the decision making and minimize the overall planning required time, introducing automatic optimization techniques. The principal idea of these techniques is the construction and minimization of a cost function considering certain prescribed parameters. By minimizing the cost function, the optimal seeds distribution can be retrieved. Therefore a successful minimization algorithm has to be able to search randomly the given solution space and find the global minimum, escaping existing local minima. Pouliot J. et al. [1] have successfully adopt the simulated annealing (SA) technique in the treatment planning optimization ofprostate brachytherapy. This approach is able to obtain clinically acceptable seed distributions after 20000 iterations within 15 minutes, time duration which is acceptable for treatment planning purposes prior to operation. However, the dose calculation using standard protocols induces significant uncertainties and the optimization result is limited by the dose calculation accuracy. GGEMS-Brachy, a framework using GPU accelerated Monte Carlo (MC) methods has been proposed to address the limitations of current dosimetric protocols by Lemarechal Y. et al. [2]. Within this context one can produce a dose calculation of 2% uncertainty in 9.35s / 2.5s using one or four GPUs respectively. Our goal is to combine the MC dosimetry accuracy delivered by GGEMSBrachy with the optimization procedure of SA to improve the dosimetric outcome for intraoperative radiotherapy procedures. In addition, we propose a simple yet efficient modification in the SA algorithm [1] to further decrease the computational cost of the optimization process exploiting the GPU capabilities in order to facilitate the introduction of MC simulation in treatment planning optimization.
{"title":"Prostate brachytherapy optimization using GPU accelerated simulated annealing and Monte Carlo dose simulation","authors":"Konstantinos A. Mountris, J. Bert, D. Visvikis","doi":"10.1109/NSSMIC.2016.8069622","DOIUrl":"https://doi.org/10.1109/NSSMIC.2016.8069622","url":null,"abstract":"Planning the radioactive seeds delivery during prostate brachytherapy is a critical part of the overall procedure. The planning process is time consuming and requires substantial user input and implication to ensure the optimal decision on the seeds' locations. Therefore efforts have been done to help in the decision making and minimize the overall planning required time, introducing automatic optimization techniques. The principal idea of these techniques is the construction and minimization of a cost function considering certain prescribed parameters. By minimizing the cost function, the optimal seeds distribution can be retrieved. Therefore a successful minimization algorithm has to be able to search randomly the given solution space and find the global minimum, escaping existing local minima. Pouliot J. et al. [1] have successfully adopt the simulated annealing (SA) technique in the treatment planning optimization ofprostate brachytherapy. This approach is able to obtain clinically acceptable seed distributions after 20000 iterations within 15 minutes, time duration which is acceptable for treatment planning purposes prior to operation. However, the dose calculation using standard protocols induces significant uncertainties and the optimization result is limited by the dose calculation accuracy. GGEMS-Brachy, a framework using GPU accelerated Monte Carlo (MC) methods has been proposed to address the limitations of current dosimetric protocols by Lemarechal Y. et al. [2]. Within this context one can produce a dose calculation of 2% uncertainty in 9.35s / 2.5s using one or four GPUs respectively. Our goal is to combine the MC dosimetry accuracy delivered by GGEMSBrachy with the optimization procedure of SA to improve the dosimetric outcome for intraoperative radiotherapy procedures. In addition, we propose a simple yet efficient modification in the SA algorithm [1] to further decrease the computational cost of the optimization process exploiting the GPU capabilities in order to facilitate the introduction of MC simulation in treatment planning optimization.","PeriodicalId":184587,"journal":{"name":"2016 IEEE Nuclear Science Symposium, Medical Imaging Conference and Room-Temperature Semiconductor Detector Workshop (NSS/MIC/RTSD)","volume":"66 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127898918","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2016-10-01DOI: 10.1109/NSSMIC.2016.8069654
P. Fernandez-Martínez, L. Ré, D. Flores, S. Hidalgo, D. Quirion, M. Ullán
The IMB-CNM (Barcelona) has developed a new vertical JFET (V-JFET) technology with the purpose of working as rad-hard switches in the HV powering scheme of the upgraded ATLAS tracker. The design of the new transistors draws upon a deep-trenched 3D technology to achieve vertical conduction and low switch-off voltage. These features prospect suitable radiation hardness for the application. The first V-JFET prototypes are now fabricated and characterized, with very promising results already meeting the application requirements. A compilation of the simulated and measured performance is shown in the contribution. To evaluate the radiation hardness, gamma irradiation has been performed and the main results are presented here.
{"title":"A new vertical JFET technology for the powering scheme of the ATLAS upgrade inner tracker","authors":"P. Fernandez-Martínez, L. Ré, D. Flores, S. Hidalgo, D. Quirion, M. Ullán","doi":"10.1109/NSSMIC.2016.8069654","DOIUrl":"https://doi.org/10.1109/NSSMIC.2016.8069654","url":null,"abstract":"The IMB-CNM (Barcelona) has developed a new vertical JFET (V-JFET) technology with the purpose of working as rad-hard switches in the HV powering scheme of the upgraded ATLAS tracker. The design of the new transistors draws upon a deep-trenched 3D technology to achieve vertical conduction and low switch-off voltage. These features prospect suitable radiation hardness for the application. The first V-JFET prototypes are now fabricated and characterized, with very promising results already meeting the application requirements. A compilation of the simulated and measured performance is shown in the contribution. To evaluate the radiation hardness, gamma irradiation has been performed and the main results are presented here.","PeriodicalId":184587,"journal":{"name":"2016 IEEE Nuclear Science Symposium, Medical Imaging Conference and Room-Temperature Semiconductor Detector Workshop (NSS/MIC/RTSD)","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115183396","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2016-10-01DOI: 10.1109/NSSMIC.2016.8069838
R. Giordano, V. Izzo, S. Perrella, A. Aloisio
In February 2016, the SuperKEKB positron-electron high-luminosity collider of the KEK laboratory (Tsukuba, Japan) started being commissioned. A dedicated commissioning detector, named BEAST2, has been used to characterize beam backgrounds before the Belle2 detector is rolled into the beams and to provide tuning parameters for Monte Carlo simulations. BEAST2 consists of a fiberglass support structure and several subdetectors mounted onto it, including time projection chambers (TPCs) and He-3 tubes. In this work, we present direct measurements of radiation-induced single event upsets in a SRAM-based FPGA device installed in BEAST2 at a distance of ∼1 m from the beam interaction point. Our goal is to provide experimental results of the expected radiation-induced configuration upset rate and power consumption variation at Belle2 and at other experiments operating in similar radiation conditions. For this study, we designed a dedicated board hosting a Xilinx Kintex-7 325T FPGA without additional active components, in such a way to be able to decouple FPGA failures from those of other devices. During the commissioning of the collider, we periodically read back the FPGA configuration in order to detect errors and we logged the power consumption on the different power domains of the device. Currents for both electron and positron rings spanned a range between 50 and 500 mA, therefore providing data about the FPGA operation in different radiation conditions.
{"title":"Soft-errors in FPGAs at the SuperKEKB interaction point","authors":"R. Giordano, V. Izzo, S. Perrella, A. Aloisio","doi":"10.1109/NSSMIC.2016.8069838","DOIUrl":"https://doi.org/10.1109/NSSMIC.2016.8069838","url":null,"abstract":"In February 2016, the SuperKEKB positron-electron high-luminosity collider of the KEK laboratory (Tsukuba, Japan) started being commissioned. A dedicated commissioning detector, named BEAST2, has been used to characterize beam backgrounds before the Belle2 detector is rolled into the beams and to provide tuning parameters for Monte Carlo simulations. BEAST2 consists of a fiberglass support structure and several subdetectors mounted onto it, including time projection chambers (TPCs) and He-3 tubes. In this work, we present direct measurements of radiation-induced single event upsets in a SRAM-based FPGA device installed in BEAST2 at a distance of ∼1 m from the beam interaction point. Our goal is to provide experimental results of the expected radiation-induced configuration upset rate and power consumption variation at Belle2 and at other experiments operating in similar radiation conditions. For this study, we designed a dedicated board hosting a Xilinx Kintex-7 325T FPGA without additional active components, in such a way to be able to decouple FPGA failures from those of other devices. During the commissioning of the collider, we periodically read back the FPGA configuration in order to detect errors and we logged the power consumption on the different power domains of the device. Currents for both electron and positron rings spanned a range between 50 and 500 mA, therefore providing data about the FPGA operation in different radiation conditions.","PeriodicalId":184587,"journal":{"name":"2016 IEEE Nuclear Science Symposium, Medical Imaging Conference and Room-Temperature Semiconductor Detector Workshop (NSS/MIC/RTSD)","volume":"49 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115205988","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2016-10-01DOI: 10.1109/NSSMIC.2016.8069944
T. Johng-ay, P. Fajardo, T. Martin, C. Ponchut, P. Douissard, M. Ruat
This paper introduces the detector simulation code DECIMO under development at the ESRF as well as some of its first applications. The code is organized as a modular Python package designed to simulate in a relatively easy and efficient way the complete detection chains of future X-ray detectors for synchrotron radiation experiments. The core of the simulation engine is based on Monte Carlo techniques implemented as efficient C/C++ routines integrated in Python objects that are interconnected to build the simulation chains. The package has been used for a preliminary investigation of various new signal processing schemes intended to push the spatial resolution of small pixel hybrid detectors, including photon counting schemes with subpixel relocation features. The paper also introduces the ESOP figure of merit, a single value describing an equivalent pixel size specifically defined to compare in a convenient way the spatial resolution of different detectors.
{"title":"DECIMO: A simulation tool to explore next generation of detectors for synchrotron radiation applications","authors":"T. Johng-ay, P. Fajardo, T. Martin, C. Ponchut, P. Douissard, M. Ruat","doi":"10.1109/NSSMIC.2016.8069944","DOIUrl":"https://doi.org/10.1109/NSSMIC.2016.8069944","url":null,"abstract":"This paper introduces the detector simulation code DECIMO under development at the ESRF as well as some of its first applications. The code is organized as a modular Python package designed to simulate in a relatively easy and efficient way the complete detection chains of future X-ray detectors for synchrotron radiation experiments. The core of the simulation engine is based on Monte Carlo techniques implemented as efficient C/C++ routines integrated in Python objects that are interconnected to build the simulation chains. The package has been used for a preliminary investigation of various new signal processing schemes intended to push the spatial resolution of small pixel hybrid detectors, including photon counting schemes with subpixel relocation features. The paper also introduces the ESOP figure of merit, a single value describing an equivalent pixel size specifically defined to compare in a convenient way the spatial resolution of different detectors.","PeriodicalId":184587,"journal":{"name":"2016 IEEE Nuclear Science Symposium, Medical Imaging Conference and Room-Temperature Semiconductor Detector Workshop (NSS/MIC/RTSD)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124257046","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2016-10-01DOI: 10.1109/NSSMIC.2016.8069669
S. Mandal, J. Saini, S. Sau, A. Chakrabarti, Wojciech Zabolotny, S. Chattopadhyay, W. Muller
The Compressed Baryonic Matter (CBM) experiment is a part of the Facility for Antiproton and Ion Research (FAIR) at Darmstadt, Germany. The challenge in CBM experiment is to measure the particles generated in nuclear collisions with unprecedented precision and statistics. To capture the data from each collision a highly time synchronized fault tolerant self-triggered electronics is required for Data Acquisition (DAQ) system that can support high data rate (up to several TB/s). Basic readout chain for CBM consists of a front-end Application Specific Integrated Circuit (ASIC) also known as X-Y Time Energy Read-out (XYTER) ASIC, a radiation hardened high speed optical transceiver board with Gigabit Transceiver (GBTx) ASIC followed by a Data Processing Board (DPB) and First Level Event Selector Interface Board (FLIB). As the first step towards the development of the readout chain, FPGA prototypes of GBTx ASIC and XYTER ASIC also known as GBTx emulator and XYTER emulator are developed. GBTx chips are connected to the XYTER in the front end through Low Voltage Differential Signalling (LVDS) electrical line also known as E-link and in the back-end with DPB using optical fiber. In this work, an FPGA-based readout chain prototype comprising of XYTER emulator, GBTx emulator, and DPB is developed where control and configuration signal of XYTER will be sent from DPB through GBTx emulator. A Python script is written in the computer to generate the control information that will be transferred to DPB through Ethernet using IPBus protocol.
{"title":"Integration of GBTx emulator with MUCH-XYTER and data processing board for CBM experiment","authors":"S. Mandal, J. Saini, S. Sau, A. Chakrabarti, Wojciech Zabolotny, S. Chattopadhyay, W. Muller","doi":"10.1109/NSSMIC.2016.8069669","DOIUrl":"https://doi.org/10.1109/NSSMIC.2016.8069669","url":null,"abstract":"The Compressed Baryonic Matter (CBM) experiment is a part of the Facility for Antiproton and Ion Research (FAIR) at Darmstadt, Germany. The challenge in CBM experiment is to measure the particles generated in nuclear collisions with unprecedented precision and statistics. To capture the data from each collision a highly time synchronized fault tolerant self-triggered electronics is required for Data Acquisition (DAQ) system that can support high data rate (up to several TB/s). Basic readout chain for CBM consists of a front-end Application Specific Integrated Circuit (ASIC) also known as X-Y Time Energy Read-out (XYTER) ASIC, a radiation hardened high speed optical transceiver board with Gigabit Transceiver (GBTx) ASIC followed by a Data Processing Board (DPB) and First Level Event Selector Interface Board (FLIB). As the first step towards the development of the readout chain, FPGA prototypes of GBTx ASIC and XYTER ASIC also known as GBTx emulator and XYTER emulator are developed. GBTx chips are connected to the XYTER in the front end through Low Voltage Differential Signalling (LVDS) electrical line also known as E-link and in the back-end with DPB using optical fiber. In this work, an FPGA-based readout chain prototype comprising of XYTER emulator, GBTx emulator, and DPB is developed where control and configuration signal of XYTER will be sent from DPB through GBTx emulator. A Python script is written in the computer to generate the control information that will be transferred to DPB through Ethernet using IPBus protocol.","PeriodicalId":184587,"journal":{"name":"2016 IEEE Nuclear Science Symposium, Medical Imaging Conference and Room-Temperature Semiconductor Detector Workshop (NSS/MIC/RTSD)","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114837009","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2016-10-01DOI: 10.1109/NSSMIC.2016.8069466
M. Aykaç, V. Panin
It is essential to have properly tuned PET scanner and data correction methods to obtain accurate quantitative images. Quality control (QC) procedure ensures reproducible performance of a clinical PET scanner. The scope of this study is to observe the stability of a PET scanner by monitoring the 511keV photopeak during a phantom/patient scan at the crystal level. In addition, during the histogramming process of the listmode data, normalization including the crystal-based deadtime model can be implemented for accurate data correction. The method of peak monitoring could be used to adjust crystal sensitivity based on the exact condition of each crystal during the patient scan in the future. This would allow for a “personalized”, improved normalization, using data already available during the data acquisition.
{"title":"Towards better normalization using photopeak monitoring from phantom/patient data in positron emission tomography (PET)","authors":"M. Aykaç, V. Panin","doi":"10.1109/NSSMIC.2016.8069466","DOIUrl":"https://doi.org/10.1109/NSSMIC.2016.8069466","url":null,"abstract":"It is essential to have properly tuned PET scanner and data correction methods to obtain accurate quantitative images. Quality control (QC) procedure ensures reproducible performance of a clinical PET scanner. The scope of this study is to observe the stability of a PET scanner by monitoring the 511keV photopeak during a phantom/patient scan at the crystal level. In addition, during the histogramming process of the listmode data, normalization including the crystal-based deadtime model can be implemented for accurate data correction. The method of peak monitoring could be used to adjust crystal sensitivity based on the exact condition of each crystal during the patient scan in the future. This would allow for a “personalized”, improved normalization, using data already available during the data acquisition.","PeriodicalId":184587,"journal":{"name":"2016 IEEE Nuclear Science Symposium, Medical Imaging Conference and Room-Temperature Semiconductor Detector Workshop (NSS/MIC/RTSD)","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114554210","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2016-10-01DOI: 10.1109/NSSMIC.2016.8069734
P. Menge, Kan Yang, Michael McLaughlin, B. Bacon
Silicon photomultipliers (SiPMs) are attractive replacements for photomultiplier tubes (PMTs). However, many radiation detector applications require large volumes of monolithic scintillator and correspondingly large numbers of SiPMs. When multiples of SiPMs are used, the dark count noise and cost increase proportionally with the surface area covered. When too few SiPMs are used, non-uniformity of light collection degrades the energy resolution of the detector. Strategic placement of a limited number of SiPMs on a large scintillator can reduce the number of SiPMs necessary and decrease the cost-to-performance ratio. Simulations and experiments have been performed to find general guidelines regarding optimal positioning of SiPMs on large NaI(Tl) crystal scintillators. For example, if the SiPMs are placed near edges and vertices on one cuboid face, the number of SiPMs necessary to achieve adequate energy resolution need only cover 40% or less of the light output face.
{"title":"Efficient positioning of silicon photomultipliers on large scintillation crystals","authors":"P. Menge, Kan Yang, Michael McLaughlin, B. Bacon","doi":"10.1109/NSSMIC.2016.8069734","DOIUrl":"https://doi.org/10.1109/NSSMIC.2016.8069734","url":null,"abstract":"Silicon photomultipliers (SiPMs) are attractive replacements for photomultiplier tubes (PMTs). However, many radiation detector applications require large volumes of monolithic scintillator and correspondingly large numbers of SiPMs. When multiples of SiPMs are used, the dark count noise and cost increase proportionally with the surface area covered. When too few SiPMs are used, non-uniformity of light collection degrades the energy resolution of the detector. Strategic placement of a limited number of SiPMs on a large scintillator can reduce the number of SiPMs necessary and decrease the cost-to-performance ratio. Simulations and experiments have been performed to find general guidelines regarding optimal positioning of SiPMs on large NaI(Tl) crystal scintillators. For example, if the SiPMs are placed near edges and vertices on one cuboid face, the number of SiPMs necessary to achieve adequate energy resolution need only cover 40% or less of the light output face.","PeriodicalId":184587,"journal":{"name":"2016 IEEE Nuclear Science Symposium, Medical Imaging Conference and Room-Temperature Semiconductor Detector Workshop (NSS/MIC/RTSD)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116901182","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2016-10-01DOI: 10.1109/NSSMIC.2016.8069554
Li Tao, H. Daghighian, C. Levin
In this paper, we further explore the optical property modulation-based method for ionizing radiation photon detection in PET as a potential new direction to dramatically improve the coincidence time resolution. We compare the performance of three detector crystals for this method including two types of cadmium telluride (CdTe) crystals and one bismuth silicon oxide (BSO) crystal under high bias voltages up to 3500V. We first show that the induced current flow in the detector crystal determines the strength of the optical property modulation signal due to ionization. A larger resistivity is favorable for reducing the dark current (noise) in the crystal and facilitates the detection of weak optical property modulation signals. In addition, we show that BSO is a potential candidate detector material. When biased at 3500 V, it has comparable modulation signal sensitivity as CdTe biased at 1000V, but with higher resistivity (lower noise), larger 511 keV photon attenuation coefficient, lower price, better crystal surface finish quality, and less toxicity. By studying the dependence of modulation signal amplitude on crystal bias voltage, we show that the modulation signal amplitude (induced by both UV laser diode and Ge-68 source) is linearly proportional to crystal bias voltage with a linear fit R factor of around 0.95. The modulation signal amplitude induced by UV laser diode irradiation increases from 0% to 2% (normalized to the average signal level) for both CdTe and BSO under crystal bias voltage from 0V to 3500V. The modulation signal amplitude induced by Ge-68 irradiation increases from 0% to 12% for CdTe under crystal bias voltage from 0V to 1500 V, and increases from 0% to 10% for BSO under crystal bias voltage from 0V to 3500 V. Therefore the electron multiplication effect (with high crystal bias) shows promise to significantly boost the modulation signal amplitude with the ultimate goal to achieve single 511 keV photon detection.
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