Pub Date : 2003-12-01DOI: 10.1109/NSSMIC.2003.1351933
R. Angstadt, G. Brooijmans, D. Chapin, M. Clements, D. Cutts, S. Fuess, A. Haas, R. Hauser, M. Johnson, A. Kulyavtsev, M. Mulders, P. Padley, D. Petravick, R. Rechemacher, S. Snyder, G. Watts
The Level 3 Trigger/Data Acquisition system (L3DAQ) for the DZERO detector was redesigned from scratch for the Fermilab Tevatron's RunII. The L3DAQ moves data at a rate of 250 MB/sec from 63 readout crates to one of 82 Level 3 Trigger farm nodes over Ethernet. The readout crates are VME based, and each consists of a number of detector specific digitizer cards and a controller. The readout crates also contain a single L3DAQ Single Board Computer (SBC). Crate data size per event ranges from several kilobytes up to 24 kilobytes for the largest; and the data must he collected from each of the VME cards at an event readout rate of 1 kHz. The SBC, a VMIC 7750, is an off-the-shelf component and runs Linux with several common and custom patches. This paper will describe the custom driver we've written to control the VME readout, modifications to the Linux kernel, and the user level readout code.
{"title":"The Linux-based single board computer for front end crates in the DZERO Data Acquisition System","authors":"R. Angstadt, G. Brooijmans, D. Chapin, M. Clements, D. Cutts, S. Fuess, A. Haas, R. Hauser, M. Johnson, A. Kulyavtsev, M. Mulders, P. Padley, D. Petravick, R. Rechemacher, S. Snyder, G. Watts","doi":"10.1109/NSSMIC.2003.1351933","DOIUrl":"https://doi.org/10.1109/NSSMIC.2003.1351933","url":null,"abstract":"The Level 3 Trigger/Data Acquisition system (L3DAQ) for the DZERO detector was redesigned from scratch for the Fermilab Tevatron's RunII. The L3DAQ moves data at a rate of 250 MB/sec from 63 readout crates to one of 82 Level 3 Trigger farm nodes over Ethernet. The readout crates are VME based, and each consists of a number of detector specific digitizer cards and a controller. The readout crates also contain a single L3DAQ Single Board Computer (SBC). Crate data size per event ranges from several kilobytes up to 24 kilobytes for the largest; and the data must he collected from each of the VME cards at an event readout rate of 1 kHz. The SBC, a VMIC 7750, is an off-the-shelf component and runs Linux with several common and custom patches. This paper will describe the custom driver we've written to control the VME readout, modifications to the Linux kernel, and the user level readout code.","PeriodicalId":186175,"journal":{"name":"2003 IEEE Nuclear Science Symposium. Conference Record (IEEE Cat. No.03CH37515)","volume":"196 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123232429","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 : 2003-12-01DOI: 10.1109/NSSMIC.2003.1352440
T.-S. Lee, W. Segars, B. Tsui
The purpose of the study is to investigate the effect of cardiac gating in myocardial SPECT obtained from different gating schemes and image reconstruction methods using the 4D NURBS-based cardiac-torso (NCAT) phantom. We generated 144 phantoms over a cardiac cycle modeling a typical Tc-99m Sestamibi study. The cardiac cycle was divided into different gating schemes (8, 12, 16, and 24 gates) by summing combinations of these phantoms. For each gate, we generated projection data using an analytical projector that included the effects of attenuation, collimator-detector response and scatter, and reconstructed using different image reconstruction methods including FBP, OS-EM (with and without attenuation, scatter, and collimator-detector response corrections), and a 4D MAP-RBI-EM algorithm. The amount of motion blur (measured by mean square error) and percentage fluctuation of the reconstructed images were evaluated as measures for temporal resolution and noise level. The ejection fraction was also calculated to further evaluate the different gating schemes and reconstruction methods. The results show a dramatic improvement in temporal resolution in gated versus ungated images. The level of noise was found to increase significantly with an increase in the number of gates. Using a smaller number of gates was found to have a higher variation in estimating the ejection fraction. For each gating scheme, FBP and OS-EM without correction were found to have the poorest temporal resolution and the highest level of image noise while OS-EM with corrections was found to significantly improve temporal resolution and reduce image noise. We conclude that the 4D NCAT phantom is a useful tool in the study of optimal gating schemes and 4D image reconstruction methods for improved gated myocardial SPECT.
{"title":"A study of the effect of cardiac gating in myocardial SPECT using the 4D NCAT","authors":"T.-S. Lee, W. Segars, B. Tsui","doi":"10.1109/NSSMIC.2003.1352440","DOIUrl":"https://doi.org/10.1109/NSSMIC.2003.1352440","url":null,"abstract":"The purpose of the study is to investigate the effect of cardiac gating in myocardial SPECT obtained from different gating schemes and image reconstruction methods using the 4D NURBS-based cardiac-torso (NCAT) phantom. We generated 144 phantoms over a cardiac cycle modeling a typical Tc-99m Sestamibi study. The cardiac cycle was divided into different gating schemes (8, 12, 16, and 24 gates) by summing combinations of these phantoms. For each gate, we generated projection data using an analytical projector that included the effects of attenuation, collimator-detector response and scatter, and reconstructed using different image reconstruction methods including FBP, OS-EM (with and without attenuation, scatter, and collimator-detector response corrections), and a 4D MAP-RBI-EM algorithm. The amount of motion blur (measured by mean square error) and percentage fluctuation of the reconstructed images were evaluated as measures for temporal resolution and noise level. The ejection fraction was also calculated to further evaluate the different gating schemes and reconstruction methods. The results show a dramatic improvement in temporal resolution in gated versus ungated images. The level of noise was found to increase significantly with an increase in the number of gates. Using a smaller number of gates was found to have a higher variation in estimating the ejection fraction. For each gating scheme, FBP and OS-EM without correction were found to have the poorest temporal resolution and the highest level of image noise while OS-EM with corrections was found to significantly improve temporal resolution and reduce image noise. We conclude that the 4D NCAT phantom is a useful tool in the study of optimal gating schemes and 4D image reconstruction methods for improved gated myocardial SPECT.","PeriodicalId":186175,"journal":{"name":"2003 IEEE Nuclear Science Symposium. Conference Record (IEEE Cat. No.03CH37515)","volume":"60 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127938695","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 : 2003-12-01DOI: 10.1109/NSSMIC.2003.1352363
J. Griffiths, R. Speller, G. Royle, A. Horrocks, A. Olivo, S. Pani, R. Longo, D. Dreossi, S. Spencer, M. Robbins, D.P. Clifford, A. Hanby
The scattering properties of breast tissue have been suggested as a diagnostic tool in the early detection of breast cancer. To aid in the development of a clinical imaging system based upon these properties, a series of breast tissue samples have been subjected to diffraction microCT using the SYRMEP beamline at Elettra, Italy. Using 18 keV photons, both transmission and diffraction CT data sets were collected using a specially designed microCT system. This system was based around a finely collimated, X-ray sensitive L3Vision CCD camera and a simple rotary stage controlled using Lab View software. The images were reconstructed using routines developed in IDL. This paper presents both transmission and diffraction CT images of three samples. The samples were excised breast tissue sections known to contain either tumour, normal tissue adjacent to the tumour or a mixture of each. The results demonstrate that diffraction microCT can be used to evaluate the structure of breast tissue tumours. Registration of the transmission and diffraction CT images demonstrated that both techniques showed the same principle features in the sample and allowed the main components to be identified. However, the diffraction images demonstrated an average increase in image contrast over the transmission images. Further improvements in the collimator design used in the experiments will need to be made if detailed structure is to be seen.
{"title":"X-ray diffraction CT of excised breast tissue sections: first results from Elettra","authors":"J. Griffiths, R. Speller, G. Royle, A. Horrocks, A. Olivo, S. Pani, R. Longo, D. Dreossi, S. Spencer, M. Robbins, D.P. Clifford, A. Hanby","doi":"10.1109/NSSMIC.2003.1352363","DOIUrl":"https://doi.org/10.1109/NSSMIC.2003.1352363","url":null,"abstract":"The scattering properties of breast tissue have been suggested as a diagnostic tool in the early detection of breast cancer. To aid in the development of a clinical imaging system based upon these properties, a series of breast tissue samples have been subjected to diffraction microCT using the SYRMEP beamline at Elettra, Italy. Using 18 keV photons, both transmission and diffraction CT data sets were collected using a specially designed microCT system. This system was based around a finely collimated, X-ray sensitive L3Vision CCD camera and a simple rotary stage controlled using Lab View software. The images were reconstructed using routines developed in IDL. This paper presents both transmission and diffraction CT images of three samples. The samples were excised breast tissue sections known to contain either tumour, normal tissue adjacent to the tumour or a mixture of each. The results demonstrate that diffraction microCT can be used to evaluate the structure of breast tissue tumours. Registration of the transmission and diffraction CT images demonstrated that both techniques showed the same principle features in the sample and allowed the main components to be identified. However, the diffraction images demonstrated an average increase in image contrast over the transmission images. Further improvements in the collimator design used in the experiments will need to be made if detailed structure is to be seen.","PeriodicalId":186175,"journal":{"name":"2003 IEEE Nuclear Science Symposium. Conference Record (IEEE Cat. No.03CH37515)","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121095928","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 : 2003-12-01DOI: 10.1109/NSSMIC.2003.1351854
B. Angstadt, G. Brooijmans, D. Chapin, D. Charak, A. Clements, D. Cutts, A. Haas, R. Hauser, M. Johnson, A. Kulyavtsev, S. Mattingly, M. Mulders, P. Padley, D. Petravick, R. Rechenmacher, G. Watts, D. Zhang
The DO detector at Fermilab has been collecting data with its new, Ethernet-based Data Acquisition (DAQ) System since spring 2002. The system was built almost exclusively with commercially available components, and designed to read in event fragments at a rate of 1 kHz from about 70 VME crates, assemble the events with a typical size of 250 kB and pass them to the Level 3 trigger farm, composed of about 160 CPUs, for final event selection. Accepted events are sent to the online system to he stored on tape at an average rate of 50 Hz. The event fragments are read out over VME using Single Board Computers (SBCs) and sent to the trigger farm through 100 Mb/s and 1 Gb/s Ethernet connections via a series of Ethernet switches. This paper gives an overview of the main components of the DAQ and trigger system and reports on its performance during the first year of operation.
{"title":"Ethernet-based data acquisition system for the DO experiment at Fermilab","authors":"B. Angstadt, G. Brooijmans, D. Chapin, D. Charak, A. Clements, D. Cutts, A. Haas, R. Hauser, M. Johnson, A. Kulyavtsev, S. Mattingly, M. Mulders, P. Padley, D. Petravick, R. Rechenmacher, G. Watts, D. Zhang","doi":"10.1109/NSSMIC.2003.1351854","DOIUrl":"https://doi.org/10.1109/NSSMIC.2003.1351854","url":null,"abstract":"The DO detector at Fermilab has been collecting data with its new, Ethernet-based Data Acquisition (DAQ) System since spring 2002. The system was built almost exclusively with commercially available components, and designed to read in event fragments at a rate of 1 kHz from about 70 VME crates, assemble the events with a typical size of 250 kB and pass them to the Level 3 trigger farm, composed of about 160 CPUs, for final event selection. Accepted events are sent to the online system to he stored on tape at an average rate of 50 Hz. The event fragments are read out over VME using Single Board Computers (SBCs) and sent to the trigger farm through 100 Mb/s and 1 Gb/s Ethernet connections via a series of Ethernet switches. This paper gives an overview of the main components of the DAQ and trigger system and reports on its performance during the first year of operation.","PeriodicalId":186175,"journal":{"name":"2003 IEEE Nuclear Science Symposium. Conference Record (IEEE Cat. No.03CH37515)","volume":"63 6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115916626","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 : 2003-12-01DOI: 10.1109/NSSMIC.2003.1351928
G. Cancelo, E. Gottschalk, V. Pavlicek, M. Wang, J. Wu
The current paper studies how processor failures affect the dataflow of the Level I Trigger in the BTeV experiment proposed to run at Fermilab's Tevatron. The failure analysis is crucial for a system with over 2500 processing nodes and a number of storage units and communication links of the same order of magnitude. The failure analysis is based on models of the L1 Trigger architecture and shows the dynamics of the architecture's dataflow. The failure analysis provides insight into how system variables are affected by single component failures and provides key information to the implementation Of error recovery strategies. The analysis includes both short term failures from which the system can recover quickly and long term failures which imply a more drastic error recovery strategy. The modeling results are supported by behavioral simulations of the L1 Trigger processing BTeV's Geant Monte Carlo data.
{"title":"Failure Analysis in a highly parallel processor for Ll Triggering","authors":"G. Cancelo, E. Gottschalk, V. Pavlicek, M. Wang, J. Wu","doi":"10.1109/NSSMIC.2003.1351928","DOIUrl":"https://doi.org/10.1109/NSSMIC.2003.1351928","url":null,"abstract":"The current paper studies how processor failures affect the dataflow of the Level I Trigger in the BTeV experiment proposed to run at Fermilab's Tevatron. The failure analysis is crucial for a system with over 2500 processing nodes and a number of storage units and communication links of the same order of magnitude. The failure analysis is based on models of the L1 Trigger architecture and shows the dynamics of the architecture's dataflow. The failure analysis provides insight into how system variables are affected by single component failures and provides key information to the implementation Of error recovery strategies. The analysis includes both short term failures from which the system can recover quickly and long term failures which imply a more drastic error recovery strategy. The modeling results are supported by behavioral simulations of the L1 Trigger processing BTeV's Geant Monte Carlo data.","PeriodicalId":186175,"journal":{"name":"2003 IEEE Nuclear Science Symposium. Conference Record (IEEE Cat. No.03CH37515)","volume":"66 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129669173","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}
Y. Maravin, John Anderson, R. Angstadt, L. Babukhadia, Mrinmoy Bhattacharjee, G. Blazey, F. Borcherding, Brian Connolly, Michael Cooke, Satish Desai, P. Grannis, S. Grünendahl, Carsten Hensel, Vivek Jain, Marvin Johnson, Stephan Linn, Juan Lizarazo, Manuel Martin, Y. Mutaf, C. Nöding, J. Olsen, R. Ramirez-Gomez, S. Rapisarda, K. Stevenson, M. Tomoto, Brigitte Vachon, Thei Wijnen, N. Wilcer, Graham Wilson, Qichun Xu, K. Yip
An overview of the DO Central Track Trigger (CTT) for the Tevatron Run 2 program is presented. This newly commissioned system uses information from the DO Central Fiber Tracker and Preshower Detectors to generate trigger information for the first level of the three-tiered DO Trigger. The system delivers tracking detector trigger decisions every 132 ns, based on input data flowing at a rate of 475 Gbit per second. Initial results indicate excellent performance of the CTT. First studies of efficiency and trigger performance of the CTT are presented.
介绍了Tevatron Run 2程序的DO中央轨道触发器(CTT)的概述。该新系统使用来自DO中央光纤跟踪器和预淋浴探测器的信息，为三层DO触发器的第一级生成触发信息。该系统基于每秒475 Gbit / s的输入数据流，每132 ns提供跟踪检测器触发决策。初步结果表明，CTT具有良好的性能。本文首先对CTT的效率和触发性能进行了研究。
{"title":"First results from the central tracking trigger of the DO experiment","authors":"Y. Maravin, John Anderson, R. Angstadt, L. Babukhadia, Mrinmoy Bhattacharjee, G. Blazey, F. Borcherding, Brian Connolly, Michael Cooke, Satish Desai, P. Grannis, S. Grünendahl, Carsten Hensel, Vivek Jain, Marvin Johnson, Stephan Linn, Juan Lizarazo, Manuel Martin, Y. Mutaf, C. Nöding, J. Olsen, R. Ramirez-Gomez, S. Rapisarda, K. Stevenson, M. Tomoto, Brigitte Vachon, Thei Wijnen, N. Wilcer, Graham Wilson, Qichun Xu, K. Yip","doi":"10.1109/TNS.2004.832623","DOIUrl":"https://doi.org/10.1109/TNS.2004.832623","url":null,"abstract":"An overview of the DO Central Track Trigger (CTT) for the Tevatron Run 2 program is presented. This newly commissioned system uses information from the DO Central Fiber Tracker and Preshower Detectors to generate trigger information for the first level of the three-tiered DO Trigger. The system delivers tracking detector trigger decisions every 132 ns, based on input data flowing at a rate of 475 Gbit per second. Initial results indicate excellent performance of the CTT. First studies of efficiency and trigger performance of the CTT are presented.","PeriodicalId":186175,"journal":{"name":"2003 IEEE Nuclear Science Symposium. Conference Record (IEEE Cat. No.03CH37515)","volume":"173 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126284089","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 : 2003-12-01DOI: 10.1109/NSSMIC.2003.1351868
T. Quinn, R. Bates, M. Bruzzi, W. Cunningham, K. Mathieson, M. Moll, T. Nelson, H. Nilsson, I. Pintillie, L. Reynolds, S. Sciortino, P. Sellin, H. Strachan, B. Svensson, J. Vaitkus, M. Rahman
Measurements and simulations have been carried out using bulk and epitaxial SiC detectors. Samples were irradiated to fluences of around 10/sup 14/ hardrons/cm/sup 2/. Material of thickness 40/spl mu/m gave a charge collection efficiency of 100% dropping to around 60% at 100 /spl mu/m thickness. Detailed MEDICI simulations incorporated the main defect levels in SiC, the vanadium center, Z-center and a mid-gap level as measured by deep level transient spectroscopy and other techniques. Calculated recombination currents and charge collection efficiencies at varying fluences were comparable to experimental data. The study suggests that SiC detectors will operate up to fluences around 10/sup 16//cm/sup 2/ as required by future particle physics experiments.
{"title":"Comparison of bulk and epitaxial 4H-SiC detectors for radiation hard particle tracking","authors":"T. Quinn, R. Bates, M. Bruzzi, W. Cunningham, K. Mathieson, M. Moll, T. Nelson, H. Nilsson, I. Pintillie, L. Reynolds, S. Sciortino, P. Sellin, H. Strachan, B. Svensson, J. Vaitkus, M. Rahman","doi":"10.1109/NSSMIC.2003.1351868","DOIUrl":"https://doi.org/10.1109/NSSMIC.2003.1351868","url":null,"abstract":"Measurements and simulations have been carried out using bulk and epitaxial SiC detectors. Samples were irradiated to fluences of around 10/sup 14/ hardrons/cm/sup 2/. Material of thickness 40/spl mu/m gave a charge collection efficiency of 100% dropping to around 60% at 100 /spl mu/m thickness. Detailed MEDICI simulations incorporated the main defect levels in SiC, the vanadium center, Z-center and a mid-gap level as measured by deep level transient spectroscopy and other techniques. Calculated recombination currents and charge collection efficiencies at varying fluences were comparable to experimental data. The study suggests that SiC detectors will operate up to fluences around 10/sup 16//cm/sup 2/ as required by future particle physics experiments.","PeriodicalId":186175,"journal":{"name":"2003 IEEE Nuclear Science Symposium. Conference Record (IEEE Cat. No.03CH37515)","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130282714","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 : 2003-12-01DOI: 10.1109/NSSMIC.2003.1352412
R. Harrison, S. Dhavala, P.N. Kumar, Y. Shao, T. Lewellen
SimSET (a Simulation System for Emission Tomography) incorporates importance sampling (IS) to accelerate emission tomography simulations. To this point IS has been used in the object being imaged, but not in the collimator. This is an effective strategy for simulations using geometric or perfect-absorber collimators, but breaks down when more realistic collimators are simulated. We are improving the efficiency of collimator simulation with algorithms that complement the IS algorithms used in the object. Recent improvements to the IS in the object have led to many more photons passing through the collimator without intersecting the septa. However, the photons that do intersect septa have much higher weights, resulting in poor quality factors if they are detected. The collimator IS algorithms force these high-weight photons either to penetrate the septa or to scatter toward the detector and then penetrate the septa. This reduces the weights of the photons, improve detection efficiency, and raise the quality factor. The new algorithms are currently focused on collimators for position emission tomography (PET), but the underlying techniques are more broadly applicable.
{"title":"Importance sampling in PET collimator simulations","authors":"R. Harrison, S. Dhavala, P.N. Kumar, Y. Shao, T. Lewellen","doi":"10.1109/NSSMIC.2003.1352412","DOIUrl":"https://doi.org/10.1109/NSSMIC.2003.1352412","url":null,"abstract":"SimSET (a Simulation System for Emission Tomography) incorporates importance sampling (IS) to accelerate emission tomography simulations. To this point IS has been used in the object being imaged, but not in the collimator. This is an effective strategy for simulations using geometric or perfect-absorber collimators, but breaks down when more realistic collimators are simulated. We are improving the efficiency of collimator simulation with algorithms that complement the IS algorithms used in the object. Recent improvements to the IS in the object have led to many more photons passing through the collimator without intersecting the septa. However, the photons that do intersect septa have much higher weights, resulting in poor quality factors if they are detected. The collimator IS algorithms force these high-weight photons either to penetrate the septa or to scatter toward the detector and then penetrate the septa. This reduces the weights of the photons, improve detection efficiency, and raise the quality factor. The new algorithms are currently focused on collimators for position emission tomography (PET), but the underlying techniques are more broadly applicable.","PeriodicalId":186175,"journal":{"name":"2003 IEEE Nuclear Science Symposium. Conference Record (IEEE Cat. No.03CH37515)","volume":" 2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133122922","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 : 2003-12-01DOI: 10.1109/NSSMIC.2003.1352404
X. Song, E. Frey, X. He, W. Segars, B. Tsui
We have previously developed a model-based method to compensate for the crosstalk in simultaneous acquisition of Tc-99m stress and Tl-201 rest myocardial perfusion SPECT. The purpose of this study is to evaluate the performance of this method in terms of a defect detection task using a mathematical Channelized Hoteling Observer (CHO) study. In this study we also optimized the iteration number in reconstruction of Tl distributions. A population of male and female NCAT phantoms were used to realistically model variation in patients. Both defect-free and defect-present data of Tc and Tl were simulated using the SimSET/PHG codes and our newly developed and validated angular response function (ARF) method to mimic simultaneous acquisition and separate acquisition. Poisson noise was modeled at clinically realistic levels. The Tl data were reconstructed using filtered backprojection (FBP) and ordered subset expectation maximization (OSEM) algorithms for up to 20 iterations with and without the model-based crosstalk compensation (MBC). CHO methodology and receiver operating characteristic (ROC) analysis were applied to short axis Tl images to obtain ROC curves and area under ROC curves (AUC). The AUC values were compared with those from separately acquired data reconstructed using FBP and OSEM algorithms. The results show that a relatively small number of iteration (/spl sim/3) is optimal for the postreconstruction filtering cutoff frequency of 0.16 pixel/sup -1/ used in this study. Also, the AUC values obtained with the MBC were significantly better than those without crosstalk compensation and those with the FBP reconstruction method applied to the separately acquired data.
{"title":"A mathematical observer study for evaluation of a model-based compensation method for crosstalk in simultaneous dual isotope SPECT","authors":"X. Song, E. Frey, X. He, W. Segars, B. Tsui","doi":"10.1109/NSSMIC.2003.1352404","DOIUrl":"https://doi.org/10.1109/NSSMIC.2003.1352404","url":null,"abstract":"We have previously developed a model-based method to compensate for the crosstalk in simultaneous acquisition of Tc-99m stress and Tl-201 rest myocardial perfusion SPECT. The purpose of this study is to evaluate the performance of this method in terms of a defect detection task using a mathematical Channelized Hoteling Observer (CHO) study. In this study we also optimized the iteration number in reconstruction of Tl distributions. A population of male and female NCAT phantoms were used to realistically model variation in patients. Both defect-free and defect-present data of Tc and Tl were simulated using the SimSET/PHG codes and our newly developed and validated angular response function (ARF) method to mimic simultaneous acquisition and separate acquisition. Poisson noise was modeled at clinically realistic levels. The Tl data were reconstructed using filtered backprojection (FBP) and ordered subset expectation maximization (OSEM) algorithms for up to 20 iterations with and without the model-based crosstalk compensation (MBC). CHO methodology and receiver operating characteristic (ROC) analysis were applied to short axis Tl images to obtain ROC curves and area under ROC curves (AUC). The AUC values were compared with those from separately acquired data reconstructed using FBP and OSEM algorithms. The results show that a relatively small number of iteration (/spl sim/3) is optimal for the postreconstruction filtering cutoff frequency of 0.16 pixel/sup -1/ used in this study. Also, the AUC values obtained with the MBC were significantly better than those without crosstalk compensation and those with the FBP reconstruction method applied to the separately acquired data.","PeriodicalId":186175,"journal":{"name":"2003 IEEE Nuclear Science Symposium. Conference Record (IEEE Cat. No.03CH37515)","volume":"166 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131950108","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 : 2003-12-01DOI: 10.1109/NSSMIC.2003.1352586
J. Griffiths, G. Royle, R. Speller, J. Horrocks, A. Olivo, S. Pani, R. Longo, S. Spencer, M. Robbins, D.P. Clifford, A. Hanby
A detectable difference in X-ray diffraction data of healthy and diseased breast tissues has been observed. This information can be used to generate images with a higher contrast than that of conventional transmission mammography. A diffraction enhanced breast imaging (DEBI) system that simultaneously combines transmission and diffraction breast images is currently being developed. This paper presents the imaging system requirements for a clinical DEBI system. The DEBI imaging system employs a phosphor coated L3Vision CCD camera. The DEBI principle has been assessed at the SYRMEP synchrotron beamline (Elettra, Trieste) and with a purpose built mammographic X-ray imaging unit. Diffraction enhanced images have been obtained of realistic breast tissue phantoms, consisting of 4 cm thick slabs of excised breast tissue containing embedded carcinomas. The images were obtained at pre-determined momentum transfer values, allowing some tissue characterization to be achieved during imaging, as well as optimizing image contrast This paper presents the current state of the project. The spatial resolution of the diffraction images have been studied using test phantoms and suggestions are made for the collimation systems necessary for a clinical system. A correction procedure applied to the diffraction images is also presented.
{"title":"Diffraction enhanced breast imaging: assessment of realistic system requirements to improve the diagnostic capabilities of mammography","authors":"J. Griffiths, G. Royle, R. Speller, J. Horrocks, A. Olivo, S. Pani, R. Longo, S. Spencer, M. Robbins, D.P. Clifford, A. Hanby","doi":"10.1109/NSSMIC.2003.1352586","DOIUrl":"https://doi.org/10.1109/NSSMIC.2003.1352586","url":null,"abstract":"A detectable difference in X-ray diffraction data of healthy and diseased breast tissues has been observed. This information can be used to generate images with a higher contrast than that of conventional transmission mammography. A diffraction enhanced breast imaging (DEBI) system that simultaneously combines transmission and diffraction breast images is currently being developed. This paper presents the imaging system requirements for a clinical DEBI system. The DEBI imaging system employs a phosphor coated L3Vision CCD camera. The DEBI principle has been assessed at the SYRMEP synchrotron beamline (Elettra, Trieste) and with a purpose built mammographic X-ray imaging unit. Diffraction enhanced images have been obtained of realistic breast tissue phantoms, consisting of 4 cm thick slabs of excised breast tissue containing embedded carcinomas. The images were obtained at pre-determined momentum transfer values, allowing some tissue characterization to be achieved during imaging, as well as optimizing image contrast This paper presents the current state of the project. The spatial resolution of the diffraction images have been studied using test phantoms and suggestions are made for the collimation systems necessary for a clinical system. A correction procedure applied to the diffraction images is also presented.","PeriodicalId":186175,"journal":{"name":"2003 IEEE Nuclear Science Symposium. Conference Record (IEEE Cat. No.03CH37515)","volume":"189 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132599711","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：