Pub Date : 2012-11-01DOI: 10.1109/NSSMIC.2012.6551294
V. Popov, H. Mkrtchyan
A new photomultiplier tube active base was designed and tested. The base combines active voltage division circuit and fast amplifier, powered by the current flowing through voltage divider. This base is developed to upgrade older photomultiplier bases of Jefferson Lab lead-tungsten calorimeter (about ~1200 crystals of PbWO4 from the PrimEx experimental setup). This is needed for the extension of detectors' rate capability to meet requirements of new Hall C proposal PR12-11-102 of measurements of the LIT separated cross sections and their ratio R = αL/αT in neutral-pion p(e,e'π0)p deep exclusive and p(e,e'no)X semi-inclusive scattering regions. New active base is direct replacement of older passive base circuit without adding of additional power or signal lines. However, it extends detectors rate capability with factor over 20. Moreover, transistorized voltage divider improves detector's amplitude resolution due to reduction of photomultiplier gain dependence from tube anode current. The PMT active base is the invention disclosed in V. Popov's U.S. Patent No. 6,791,269, which successfully works over ten years in several Jefferson Lab Cherenkov detectors. The following design is a new revised and improved electronic circuit with better gain stability and linearity in challenge to meet requirements of new Hall C experimental setup. New active base performance was tested using fast LED light source and Pr:LuAG scintillator and gamma sources. Electronics radiation hardness was tested on JLab accelerator. Results of testing R4125 Hamamatsu photomultiplier tube in new active base are presented.
{"title":"New photomultiplier active base for Hall C jefferson lab lead tungstate calorimeter","authors":"V. Popov, H. Mkrtchyan","doi":"10.1109/NSSMIC.2012.6551294","DOIUrl":"https://doi.org/10.1109/NSSMIC.2012.6551294","url":null,"abstract":"A new photomultiplier tube active base was designed and tested. The base combines active voltage division circuit and fast amplifier, powered by the current flowing through voltage divider. This base is developed to upgrade older photomultiplier bases of Jefferson Lab lead-tungsten calorimeter (about ~1200 crystals of PbWO4 from the PrimEx experimental setup). This is needed for the extension of detectors' rate capability to meet requirements of new Hall C proposal PR12-11-102 of measurements of the LIT separated cross sections and their ratio R = αL/αT in neutral-pion p(e,e'π0)p deep exclusive and p(e,e'no)X semi-inclusive scattering regions. New active base is direct replacement of older passive base circuit without adding of additional power or signal lines. However, it extends detectors rate capability with factor over 20. Moreover, transistorized voltage divider improves detector's amplitude resolution due to reduction of photomultiplier gain dependence from tube anode current. The PMT active base is the invention disclosed in V. Popov's U.S. Patent No. 6,791,269, which successfully works over ten years in several Jefferson Lab Cherenkov detectors. The following design is a new revised and improved electronic circuit with better gain stability and linearity in challenge to meet requirements of new Hall C experimental setup. New active base performance was tested using fast LED light source and Pr:LuAG scintillator and gamma sources. Electronics radiation hardness was tested on JLab accelerator. Results of testing R4125 Hamamatsu photomultiplier tube in new active base are presented.","PeriodicalId":187728,"journal":{"name":"2012 IEEE Nuclear Science Symposium and Medical Imaging Conference Record (NSS/MIC)","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124462127","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 : 2012-10-29DOI: 10.1109/NSSMIC.2012.6551943
V. Babentsov, F. Sizov, J. Franc, P. Fochuk, G. Yang, A. Bolotnikov, R. James
We investigated dislocation-related electronic states induced by dislocation motion in CdTe-based semiconductors. Dislocations cause various types of electronic defect states in the bandgap of semiconductors, namely, defects created by different types of dislocations, and those due to an impurity or native defect segregated around the dislocations. The aim of this work was to further clarify, on the basis of an analysis of the lattice deformation, whether these defects belong to either the Te or Cd sublattice and to formulate a model describing such defects.
{"title":"Dislocations and defect structure around micro-indentations and Te precipitates in CdTe","authors":"V. Babentsov, F. Sizov, J. Franc, P. Fochuk, G. Yang, A. Bolotnikov, R. James","doi":"10.1109/NSSMIC.2012.6551943","DOIUrl":"https://doi.org/10.1109/NSSMIC.2012.6551943","url":null,"abstract":"We investigated dislocation-related electronic states induced by dislocation motion in CdTe-based semiconductors. Dislocations cause various types of electronic defect states in the bandgap of semiconductors, namely, defects created by different types of dislocations, and those due to an impurity or native defect segregated around the dislocations. The aim of this work was to further clarify, on the basis of an analysis of the lattice deformation, whether these defects belong to either the Te or Cd sublattice and to formulate a model describing such defects.","PeriodicalId":187728,"journal":{"name":"2012 IEEE Nuclear Science Symposium and Medical Imaging Conference Record (NSS/MIC)","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131739463","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 : 2012-10-29DOI: 10.1109/NSSMIC.2012.6551581
L. Imbert, P. Marie, E. Galbrun, S. Poussier, D. Wolf, G. Karcher, A. Noel
Significant improvements have been achieved recently for gamma-cameras dedicated to myocardial perfusion imaging such as the DSPECT camera. These cameras involve new Cadmium-Zinc-Telluride (CZT) detectors and original "heart-centric" collimation systems and up to now, they have not been analyzed through Monte-Carlo simulations modeling systems. This study was aimed at analyzing the DSPECT camera by using the "Geant4 Application for Emission Tomography" (GATE). This Monte-Carlo simulation tool is commonly used for SPECT and PET imaging and is based upon a modeling of detectors response and of radiations interactions. The DSPECT gamma-camera involved 9 mobile blocks of pixelated CZT detectors with a wide-angle square-hole tungsten collimator system. A total of 120 projections is recorded by each block by means of a 'region-centric' acquisition. Placements and movements of detector-blocks were tried to be simulated by GATE, as well as the detector response in terms of count sensitivity and spatial and energy resolutions. This simulation was applied to point and linear sources of 99mTc and simulation results were compared to what was obtained by the real recording of such a point source. The real and simulated recorded data were both reconstructed by a specific algorithm of iterative reconstruction, which compensates for the collimatorrelated loss in spatial resolution. Excellent agreement was documented between simulated and real recording: 1) for count sensitivity with an <; 1 % difference, 2) for energy resolution, with only a 5% difference for the full width at half maximum (FWHM) of the 99mTc photopeak and 3) for spatial resolution with only a 7% difference for the full width at half maximum of the point source (simulated recording: 7.9 mm and real recording: 7.4 mm). The modeling of the recording of a point sourc
{"title":"Initial assessment of the Monte-Carlo simulation of SPECT recording with the new region-centric CZT “DSPECT” camera","authors":"L. Imbert, P. Marie, E. Galbrun, S. Poussier, D. Wolf, G. Karcher, A. Noel","doi":"10.1109/NSSMIC.2012.6551581","DOIUrl":"https://doi.org/10.1109/NSSMIC.2012.6551581","url":null,"abstract":"Significant improvements have been achieved recently for gamma-cameras dedicated to myocardial perfusion imaging such as the DSPECT camera. These cameras involve new Cadmium-Zinc-Telluride (CZT) detectors and original \"heart-centric\" collimation systems and up to now, they have not been analyzed through Monte-Carlo simulations modeling systems. This study was aimed at analyzing the DSPECT camera by using the \"Geant4 Application for Emission Tomography\" (GATE). This Monte-Carlo simulation tool is commonly used for SPECT and PET imaging and is based upon a modeling of detectors response and of radiations interactions. The DSPECT gamma-camera involved 9 mobile blocks of pixelated CZT detectors with a wide-angle square-hole tungsten collimator system. A total of 120 projections is recorded by each block by means of a 'region-centric' acquisition. Placements and movements of detector-blocks were tried to be simulated by GATE, as well as the detector response in terms of count sensitivity and spatial and energy resolutions. This simulation was applied to point and linear sources of 99mTc and simulation results were compared to what was obtained by the real recording of such a point source. The real and simulated recorded data were both reconstructed by a specific algorithm of iterative reconstruction, which compensates for the collimatorrelated loss in spatial resolution. Excellent agreement was documented between simulated and real recording: 1) for count sensitivity with an <; 1 % difference, 2) for energy resolution, with only a 5% difference for the full width at half maximum (FWHM) of the 99mTc photopeak and 3) for spatial resolution with only a 7% difference for the full width at half maximum of the point source (simulated recording: 7.9 mm and real recording: 7.4 mm). The modeling of the recording of a point sourc","PeriodicalId":187728,"journal":{"name":"2012 IEEE Nuclear Science Symposium and Medical Imaging Conference Record (NSS/MIC)","volume":"127 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130882063","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 : 2012-10-29DOI: 10.1109/NSSMIC.2012.6551511
J. Bert, H. Pérez-Ponce, S. Jan, Z. El Bitar, P. Gueth, Vesna CupJov, Hocine Chekatt, D. Benoit, D. Sarrut, Y. Boursier, D. Brasse, I. Buvat, C. Morel, D. Visvikis
Monte Carlo simulations (MCS) play a key role in medical applications. In this context GATE is a MCS platform dedicated to medical imaging and particle therapy. Yet MCS are very computationally demanding, which limits their applicability in clinical practice. Recently, graphics processing units (GPU) became, in many domains, a cost-effective solution to access high power computation. The objective of this work was to develop a GPU code targeting MCS for medical applications integrated within the GATE software. An aim was to enhance GATE computational efficiency by taking advantage of GPU architectures. We first developed a GPU framework with basic elements to run MCS for different medical applications. The implementation was based on a GPU adaptation of the Geant4 code. For each main GATE medical application, we developed a specific code from the GPU framework. Some of these GPU codes are currently being integrated in GATE as new features, and users can perform GPU computing in their GATE simulations. The acceleration factor resulting from the implementation of the tracking within the phantom on GPU was 60 for a PET simulation and 80 for a CT simulation. By using GPU architectures, we are also extending GATE to support optical imaging simulations that are heavily demanding in terms of computational resources. Radiation therapy applications currently supported by GATE V6.2 are also being adapted to run on hybrid GPU/CPU architectures.
{"title":"Hybrid GATE: A GPU/CPU implementation for imaging and therapy applications","authors":"J. Bert, H. Pérez-Ponce, S. Jan, Z. El Bitar, P. Gueth, Vesna CupJov, Hocine Chekatt, D. Benoit, D. Sarrut, Y. Boursier, D. Brasse, I. Buvat, C. Morel, D. Visvikis","doi":"10.1109/NSSMIC.2012.6551511","DOIUrl":"https://doi.org/10.1109/NSSMIC.2012.6551511","url":null,"abstract":"Monte Carlo simulations (MCS) play a key role in medical applications. In this context GATE is a MCS platform dedicated to medical imaging and particle therapy. Yet MCS are very computationally demanding, which limits their applicability in clinical practice. Recently, graphics processing units (GPU) became, in many domains, a cost-effective solution to access high power computation. The objective of this work was to develop a GPU code targeting MCS for medical applications integrated within the GATE software. An aim was to enhance GATE computational efficiency by taking advantage of GPU architectures. We first developed a GPU framework with basic elements to run MCS for different medical applications. The implementation was based on a GPU adaptation of the Geant4 code. For each main GATE medical application, we developed a specific code from the GPU framework. Some of these GPU codes are currently being integrated in GATE as new features, and users can perform GPU computing in their GATE simulations. The acceleration factor resulting from the implementation of the tracking within the phantom on GPU was 60 for a PET simulation and 80 for a CT simulation. By using GPU architectures, we are also extending GATE to support optical imaging simulations that are heavily demanding in terms of computational resources. Radiation therapy applications currently supported by GATE V6.2 are also being adapted to run on hybrid GPU/CPU architectures.","PeriodicalId":187728,"journal":{"name":"2012 IEEE Nuclear Science Symposium and Medical Imaging Conference Record (NSS/MIC)","volume":"86 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133380034","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 : 2012-10-29DOI: 10.1109/NSSMIC.2012.6551539
C. Mory, Vincent Auvray, Bo Zhang, M. Grass, Dirk Schafer, F. Peyrin, S. Rit, P. Douek, L. Boussel
Cardiac C-Arm computed tomography leads to a view-starved reconstruction problem because of electrocardiogram gating. Reconstruction with the Feldkamp, Davis and Kress method (FDK) generates large streak artifacts in the reconstructed volumes, hampering the medical interpretation. In order to remove these artifacts, deconvolution techniques have been proposed. In this paper, we start from a recent inverse filtering method developed for streak artifact removal. Two ways to improve upon this method are described. It is then proposed to replace inverse filtering with an iterative deconvolution scheme. Finally, we show that the iterative deconvolution method can itself be replaced by iterative filtered back projection (IFBP). The IFBP approach is flexible and could be used in a broad range of applications, while the improved inverse filtering approaches are computationally less demanding and better suited for time-critical applications.
{"title":"Deconvolution for limited-view streak artifacts removal: improvements upon an existing approach","authors":"C. Mory, Vincent Auvray, Bo Zhang, M. Grass, Dirk Schafer, F. Peyrin, S. Rit, P. Douek, L. Boussel","doi":"10.1109/NSSMIC.2012.6551539","DOIUrl":"https://doi.org/10.1109/NSSMIC.2012.6551539","url":null,"abstract":"Cardiac C-Arm computed tomography leads to a view-starved reconstruction problem because of electrocardiogram gating. Reconstruction with the Feldkamp, Davis and Kress method (FDK) generates large streak artifacts in the reconstructed volumes, hampering the medical interpretation. In order to remove these artifacts, deconvolution techniques have been proposed. In this paper, we start from a recent inverse filtering method developed for streak artifact removal. Two ways to improve upon this method are described. It is then proposed to replace inverse filtering with an iterative deconvolution scheme. Finally, we show that the iterative deconvolution method can itself be replaced by iterative filtered back projection (IFBP). The IFBP approach is flexible and could be used in a broad range of applications, while the improved inverse filtering approaches are computationally less demanding and better suited for time-critical applications.","PeriodicalId":187728,"journal":{"name":"2012 IEEE Nuclear Science Symposium and Medical Imaging Conference Record (NSS/MIC)","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123430725","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 : 2012-10-29DOI: 10.1109/NSSMIC.2012.6551963
S. Egarievwe, A. L. Adams, Mebougna L. Drabo, M. Ashford, R. Pinder, Dominique E. Jones, A. Kassu, W. Chan, Ge Yang, G. Camarda, A. Bolotnikov, R. James
Despite immense endeavor invested in optimizing the crystal growth parameters and the post growth improvement methodologies proposed by numerous studies, there are still unresolved shortcomings of CdZnTe crystals to produce commercial-grade CdZnTe detectors. Post-growth thermal annealing under Zn, Te, or Cd vapor overpressure at various temperature have been the approach attempted to improve the crystallinity of CdZnTe crystals. This paper presents results of post growth annealing of CdZnTe detectors that shows both reduction in the sizes of Te inclusions and the migration of the inclusions towards the high-temperature side of the crystal. Two set of annealing experiments were made. The first is annealing under Cd vapor overpressure in vacuum at 600 °C for 45 minutes at a temperature gradient of 10 °C/cm. The second set of CdZnTe post-growth annealing experiments was carried out at 700 °C CdZnTe annealing temperature with the Cadmium temperature at 650 °C, 30 minutes annealing time, and temperature gradient of 10 °C/cm. The reduction in the sizes of Te inclusions ranges from 8% to 38%.
{"title":"Study of the diffusion of Te inclusions in CdZnTe nuclear detectors in post-growth annealing","authors":"S. Egarievwe, A. L. Adams, Mebougna L. Drabo, M. Ashford, R. Pinder, Dominique E. Jones, A. Kassu, W. Chan, Ge Yang, G. Camarda, A. Bolotnikov, R. James","doi":"10.1109/NSSMIC.2012.6551963","DOIUrl":"https://doi.org/10.1109/NSSMIC.2012.6551963","url":null,"abstract":"Despite immense endeavor invested in optimizing the crystal growth parameters and the post growth improvement methodologies proposed by numerous studies, there are still unresolved shortcomings of CdZnTe crystals to produce commercial-grade CdZnTe detectors. Post-growth thermal annealing under Zn, Te, or Cd vapor overpressure at various temperature have been the approach attempted to improve the crystallinity of CdZnTe crystals. This paper presents results of post growth annealing of CdZnTe detectors that shows both reduction in the sizes of Te inclusions and the migration of the inclusions towards the high-temperature side of the crystal. Two set of annealing experiments were made. The first is annealing under Cd vapor overpressure in vacuum at 600 °C for 45 minutes at a temperature gradient of 10 °C/cm. The second set of CdZnTe post-growth annealing experiments was carried out at 700 °C CdZnTe annealing temperature with the Cadmium temperature at 650 °C, 30 minutes annealing time, and temperature gradient of 10 °C/cm. The reduction in the sizes of Te inclusions ranges from 8% to 38%.","PeriodicalId":187728,"journal":{"name":"2012 IEEE Nuclear Science Symposium and Medical Imaging Conference Record (NSS/MIC)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130070767","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 : 2012-10-27DOI: 10.1109/NSSMIC.2012.6551895
F. Tahavori, M. Alnowami, K. Wells
In this present study, tumour (3D) locations are predicted via external surface motion, extracted from abdomen/thoracic surface measurements that can be used to enhance dose targeting in external beam radiotherapy. Canonical Correlation Analysis (CCA) is applied to the surface and tumour motion data to maximise the correlation between them. This correlation is exploited for motion prediction [1]. Nine dynamic CT datasets were used to extract the surface and tumour motion and to create the Canonical Correlation model (CCM). Gaussian Mixture Regression (GMR) and Adaptive Kernel Density Estimation (AKDE) were trained on these nine datasets to predict the respiratory signal by updating the surface motion and CCM. A leave-one-out method was used to evaluate and compare the performance of GMR and AKDE in predicting the tumour motion.
{"title":"A comparison between adaptive kernel density estimation and Gaussian Mixture Regression for real-time tumour motion prediction from external surface motion","authors":"F. Tahavori, M. Alnowami, K. Wells","doi":"10.1109/NSSMIC.2012.6551895","DOIUrl":"https://doi.org/10.1109/NSSMIC.2012.6551895","url":null,"abstract":"In this present study, tumour (3D) locations are predicted via external surface motion, extracted from abdomen/thoracic surface measurements that can be used to enhance dose targeting in external beam radiotherapy. Canonical Correlation Analysis (CCA) is applied to the surface and tumour motion data to maximise the correlation between them. This correlation is exploited for motion prediction [1]. Nine dynamic CT datasets were used to extract the surface and tumour motion and to create the Canonical Correlation model (CCM). Gaussian Mixture Regression (GMR) and Adaptive Kernel Density Estimation (AKDE) were trained on these nine datasets to predict the respiratory signal by updating the surface motion and CCM. A leave-one-out method was used to evaluate and compare the performance of GMR and AKDE in predicting the tumour motion.","PeriodicalId":187728,"journal":{"name":"2012 IEEE Nuclear Science Symposium and Medical Imaging Conference Record (NSS/MIC)","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-10-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121545439","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 : 2012-10-27DOI: 10.1109/NSSMIC.2012.6551933
A. Rossall, M. Myronakis, A. Cherlin, I. Radley, M. Ayoub, D. Darambara
In this work, we combine a number of pixellated, high quality CdZnTe crystals of different configurations with a unique, fast electronic readout system with dynamic energy binning capabilities to develop a novel detection system capable of photon-counting, multispectral medical x-ray imaging. This technique offers significant advantages over conventional medical x-ray imaging by providing improved image quality through a reduction in beam hardening artefacts and better scatter rejection; enhanced soft tissue contrast, improving on current dual energy techniques by taking full advantage of the variation in mass attenuation coefficients of different tissues; in the development of K-edge imaging, identifying different high-Z contrast agents in a single scan; and in a significant reduction in radiation dose to the patient. This state-of-the-art readout system has eight dynamic energy bins, controlled by variable threshold voltages on comparator circuits with 16-bit counters. Using a novel technique of interchangeable CdZnTe dies, a wide range of detector configurations have been tested, providing the most complete experimental description of charge transfer effects within CdZnTe crystals. Pixellated CdZnTe crystals of thicknesses ranging between 1 and 3 mm and pixel sizes ranging between 100 and 400μm have been rigorously tested to determine the energy response, linearity, and stability of each crystal with an investigation into polarisation and charge sharing effects in order to provide a comprehensive comparison between simulation and experimental. Using the most advanced photoncounting, dynamic energy binning electronic readout system to date has allowed us to determine the optimum configuration for the electronic readout for medical x-ray imaging, providing essential information regarding the number of energy bins required for task specific medical imaging.
{"title":"Optimal architecture of CdZnTe detectors for photon counting, multispectral medical x-ray imaging: Comparison between simulation and experiment","authors":"A. Rossall, M. Myronakis, A. Cherlin, I. Radley, M. Ayoub, D. Darambara","doi":"10.1109/NSSMIC.2012.6551933","DOIUrl":"https://doi.org/10.1109/NSSMIC.2012.6551933","url":null,"abstract":"In this work, we combine a number of pixellated, high quality CdZnTe crystals of different configurations with a unique, fast electronic readout system with dynamic energy binning capabilities to develop a novel detection system capable of photon-counting, multispectral medical x-ray imaging. This technique offers significant advantages over conventional medical x-ray imaging by providing improved image quality through a reduction in beam hardening artefacts and better scatter rejection; enhanced soft tissue contrast, improving on current dual energy techniques by taking full advantage of the variation in mass attenuation coefficients of different tissues; in the development of K-edge imaging, identifying different high-Z contrast agents in a single scan; and in a significant reduction in radiation dose to the patient. This state-of-the-art readout system has eight dynamic energy bins, controlled by variable threshold voltages on comparator circuits with 16-bit counters. Using a novel technique of interchangeable CdZnTe dies, a wide range of detector configurations have been tested, providing the most complete experimental description of charge transfer effects within CdZnTe crystals. Pixellated CdZnTe crystals of thicknesses ranging between 1 and 3 mm and pixel sizes ranging between 100 and 400μm have been rigorously tested to determine the energy response, linearity, and stability of each crystal with an investigation into polarisation and charge sharing effects in order to provide a comprehensive comparison between simulation and experimental. Using the most advanced photoncounting, dynamic energy binning electronic readout system to date has allowed us to determine the optimum configuration for the electronic readout for medical x-ray imaging, providing essential information regarding the number of energy bins required for task specific medical imaging.","PeriodicalId":187728,"journal":{"name":"2012 IEEE Nuclear Science Symposium and Medical Imaging Conference Record (NSS/MIC)","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-10-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117263059","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 : 2012-10-01DOI: 10.1109/NSSMIC.2012.6551691
Jung Woo Yu, S. Woo, Y. Lee, I. Ko, R. Yoo, J. Kang, Byung Il Kim, Y. Chung, Sang-Moo Lim, KyeongMin Kim
The acute organ motion estimation in multimodal imaging improves quality of diagnosis and therapy of tumor. It is particularly important in the organ related involuntary movement such as lung and liver. The aim of this study was to compare the region specific motion in rodent using radioactive molecular sieve PET image and MRI image. The molecular sieve was contained 0.37 MBq F-18 and coated with hydrogel. For comparison of internal and external motion, molecular sieve was placed inside lung and liver and attached on the surface of each organ region in SD-rat. PET study was performed using a small animal PET scanner (Inveon) after IV injection of FDG 37 MBq/0.2 mL. List-mode data was synchronized with respiratory gating trigger signal from external monitoring system (Biovet). MRI study was performed using 3-T clinical MRI system (Magnetom Tim Trio) with human wrist coil. Coronal MRI images were acquired using T2-weighted turbo spin echo (TSE) sequence with respiratory triggering. The parameter is as follow settings: TR = 1000 ms, TE = 36 ms, FA = 20. We analyzed moving pattern and variation of movement in lung and liver region following respiratory cycle in both of PET and MRI images. Moving patterns in PET image were different in accordance with where molecular sieve was placed. The variation of lung and liver internal motion was 0.93 and 0.52 in PET image, respectively. Estimated organ motion in MRI image revealed moving pattern based on respiratory cycle. The maximum variation of lung and liver region was 1.75 and 1.36 in MRI image, respectively. We recognized organ motion was different depending on the region and the monitoring signal was overestimated compared to real motion in both of region in PET. This study demonstrated that region-specific motion estimation would realize through aid of MRI images without ext
多模态影像中的急性器官运动估计提高了肿瘤的诊断和治疗质量。它在与肺、肝等器官相关的不自主运动中尤为重要。本研究的目的是比较放射性分子筛PET图像和MRI图像对啮齿动物区域特定运动的影响。分子筛含有0.37 MBq F-18，并包被水凝胶。将分子筛置于sd大鼠肺和肝内，并附着于各脏器区域表面，比较内外运动。静脉注射FDG 37 MBq/0.2 mL后，使用小动物PET扫描仪(Inveon)进行PET研究，列表模式数据与外部监测系统(Biovet)的呼吸门控触发信号同步。MRI研究采用3-T临床MRI系统(Magnetom Tim Trio)与人体手腕线圈进行。采用呼吸触发的t2加权涡轮自旋回波(TSE)序列获取冠状面MRI图像。参数设置如下:TR = 1000ms, TE = 36ms, FA = 20。我们分析了PET和MRI图像中肺和肝区域随呼吸周期的运动模式和变化。不同位置的分子筛在PET图像上呈现不同的运动模式。肺和肝内运动的PET变化分别为0.93和0.52。在MRI图像上估计器官运动显示基于呼吸周期的运动模式。肺区和肝区在MRI图像上的最大变异分别为1.75和1.36。我们认识到不同区域的器官运动是不同的，并且在PET的两个区域的监测信号与真实运动相比被高估了。本研究表明，区域运动估计可以通过MRI图像来实现
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Pub Date : 2012-10-01DOI: 10.1109/NSSMIC.2012.6551093
J. Dolan, E. Miller, A. C. Kaplan, A. Enqvist, M. Flaska, A. Tomanin, P. Peerani, D. Chichester, S. Pozzi
At nuclear facilities, domestically and internationally, most measurement systems used for nuclear materials' control and accountability rely on He-3 detectors. Due to resource shortages, alternatives to He-3 systems are needed. This paper presents preliminary simulation and experimental efforts to develop a fast-neutron-multiplicity counter based on liquid organic scintillators. This mission also provides the opportunity to broaden the capabilities of such safeguards measurement systems to improve current neutron-multiplicity techniques and expand the scope to encompass advanced nuclear fuels.
{"title":"Passive measurement of organic-scintillator neutron signatures for nuclear safeguards applications","authors":"J. Dolan, E. Miller, A. C. Kaplan, A. Enqvist, M. Flaska, A. Tomanin, P. Peerani, D. Chichester, S. Pozzi","doi":"10.1109/NSSMIC.2012.6551093","DOIUrl":"https://doi.org/10.1109/NSSMIC.2012.6551093","url":null,"abstract":"At nuclear facilities, domestically and internationally, most measurement systems used for nuclear materials' control and accountability rely on He-3 detectors. Due to resource shortages, alternatives to He-3 systems are needed. This paper presents preliminary simulation and experimental efforts to develop a fast-neutron-multiplicity counter based on liquid organic scintillators. This mission also provides the opportunity to broaden the capabilities of such safeguards measurement systems to improve current neutron-multiplicity techniques and expand the scope to encompass advanced nuclear fuels.","PeriodicalId":187728,"journal":{"name":"2012 IEEE Nuclear Science Symposium and Medical Imaging Conference Record (NSS/MIC)","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115146378","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}
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