Pub Date : 2007-09-21DOI: 10.1016/J.NIMA.2007.05.104
A. Berdondini, M. Bettuzzi, D. Bianconi, R. Brancaccio, F. Casali, S. Cornacchia, A. Flisch, N. Lanconelli, M. Morigi, J. Hofmann, A. Pasini, A. Rossi
{"title":"Monte Carlo optimization of an industrial tomography system","authors":"A. Berdondini, M. Bettuzzi, D. Bianconi, R. Brancaccio, F. Casali, S. Cornacchia, A. Flisch, N. Lanconelli, M. Morigi, J. Hofmann, A. Pasini, A. Rossi","doi":"10.1016/J.NIMA.2007.05.104","DOIUrl":"https://doi.org/10.1016/J.NIMA.2007.05.104","url":null,"abstract":"","PeriodicalId":105619,"journal":{"name":"IEEE Nuclear Science Symposium Conference Record, 2005","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116083793","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 : 2007-01-08DOI: 10.1109/NSSMIC.2005.1596609
P. Delogu, M. Fantacci, Alessandro Preite Martinez, A. Retico, A. Stefanini, Alessandro Tata
A computer-aided detection (CADe) system for microcalcification cluster identification in mammograms has been developed in the framework of the EU-founded MammoGrid project. The CADe software is mainly based on wavelet transforms and artificial neural networks. It is able to identify microcalcifications in different datasets of mammograms (i.e. acquired with different machines and settings, digitized with different pitch and bit depth or direct digital ones). The CADe can be remotely run from GRID-connected acquisition and annotation stations, supporting clinicians from geographically distant locations in the interpretation of mammographic data. We report and discuss the system performances on different datasets of mammograms and the status of the GRID-enabled CADe analysis
{"title":"A scalable system for microcalcification cluster automated detection in a distributed mammographic database","authors":"P. Delogu, M. Fantacci, Alessandro Preite Martinez, A. Retico, A. Stefanini, Alessandro Tata","doi":"10.1109/NSSMIC.2005.1596609","DOIUrl":"https://doi.org/10.1109/NSSMIC.2005.1596609","url":null,"abstract":"A computer-aided detection (CADe) system for microcalcification cluster identification in mammograms has been developed in the framework of the EU-founded MammoGrid project. The CADe software is mainly based on wavelet transforms and artificial neural networks. It is able to identify microcalcifications in different datasets of mammograms (i.e. acquired with different machines and settings, digitized with different pitch and bit depth or direct digital ones). The CADe can be remotely run from GRID-connected acquisition and annotation stations, supporting clinicians from geographically distant locations in the interpretation of mammographic data. We report and discuss the system performances on different datasets of mammograms and the status of the GRID-enabled CADe analysis","PeriodicalId":105619,"journal":{"name":"IEEE Nuclear Science Symposium Conference Record, 2005","volume":"119 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132220460","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 : 2006-09-05DOI: 10.1109/NSSMIC.2005.1596597
W. Menges
Resistive plate chambers (RPCs) were used for the instrumentation of the iron flux return of the BaBar detector as a muon system. Unfortunately the efficiency of the original RPCs degraded rapidly with time. Limited streamer tubes (LSTs) were chosen for an upgrade of the barrel portion of the detector. The phased installation started in summer 2004 with replacing two sextants of the BaBar barrel muon system with LSTs. The modules for the remaining four sextants are under long-term test at SLAC and ready for installation, expected in 2006. The modules become inaccessible once installed in BaBar, so it is critical to select only perfectly working tubes. To accomplish this a strong QC system was established during the prototype phase, and fully implemented throughout pre-production and construction. To spot any damage during transport, the final modules are subjected to comprehensive tests at SLAC immediately after arrival and kept under long-term test till installation into BaBar. Details of these tests and results from long-term testing will be discussed. Since spring 2005 the PEP-II accelerator is running and BaBar is collecting data. First experience from data taking with the LSTs will be presented and the performance of the detector discussed
{"title":"The BaBar muon system upgrade","authors":"W. Menges","doi":"10.1109/NSSMIC.2005.1596597","DOIUrl":"https://doi.org/10.1109/NSSMIC.2005.1596597","url":null,"abstract":"Resistive plate chambers (RPCs) were used for the instrumentation of the iron flux return of the BaBar detector as a muon system. Unfortunately the efficiency of the original RPCs degraded rapidly with time. Limited streamer tubes (LSTs) were chosen for an upgrade of the barrel portion of the detector. The phased installation started in summer 2004 with replacing two sextants of the BaBar barrel muon system with LSTs. The modules for the remaining four sextants are under long-term test at SLAC and ready for installation, expected in 2006. The modules become inaccessible once installed in BaBar, so it is critical to select only perfectly working tubes. To accomplish this a strong QC system was established during the prototype phase, and fully implemented throughout pre-production and construction. To spot any damage during transport, the final modules are subjected to comprehensive tests at SLAC immediately after arrival and kept under long-term test till installation into BaBar. Details of these tests and results from long-term testing will be discussed. Since spring 2005 the PEP-II accelerator is running and BaBar is collecting data. First experience from data taking with the LSTs will be presented and the performance of the detector discussed","PeriodicalId":105619,"journal":{"name":"IEEE Nuclear Science Symposium Conference Record, 2005","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117139385","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 : 2006-04-01DOI: 10.1109/NSSMIC.2005.1596388
C. Munro, B. Koblitz, N. Santos, A. Khan
When the Large Hadron Collider (LHC) begins operation at CERN in 2007 it will produce data in volumes never before seen. Physicists around the world will manage, distribute and analyse petabytes of this data using the middleware provided by the LHC computing grid. One of the critical factors in the smooth running of this system is the performance of the file catalogues which allow users to access their files with a logical filename without knowing their physical location. This paper presents a detailed study comparing the performance and respective merits and shortcomings of two of the main catalogues: the LCG file catalogue and the gLite FiReMan catalogue
{"title":"Performance comparison of the LCG2 and gLite file catalogues","authors":"C. Munro, B. Koblitz, N. Santos, A. Khan","doi":"10.1109/NSSMIC.2005.1596388","DOIUrl":"https://doi.org/10.1109/NSSMIC.2005.1596388","url":null,"abstract":"When the Large Hadron Collider (LHC) begins operation at CERN in 2007 it will produce data in volumes never before seen. Physicists around the world will manage, distribute and analyse petabytes of this data using the middleware provided by the LHC computing grid. One of the critical factors in the smooth running of this system is the performance of the file catalogues which allow users to access their files with a logical filename without knowing their physical location. This paper presents a detailed study comparing the performance and respective merits and shortcomings of two of the main catalogues: the LCG file catalogue and the gLite FiReMan catalogue","PeriodicalId":105619,"journal":{"name":"IEEE Nuclear Science Symposium Conference Record, 2005","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127515859","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 : 2006-04-01DOI: 10.1142/9789812773678_0064
K. Andert, B. Baumbaugh, A. Brothers, A. David, H. Gunther, J. Gurrola, D. Karmgard, T. Madlem, J. Marchant, P. Mcgough, M. Mckenna, R. Ruchti, J. Thompson, M. Vigneault, L. Hernández, C. Hurlbut
Studies are presented of new blue-green to red emitting scintillator and waveshifter materials for tracking and calorimetry applications for the detection of ionizing radiation. Materials include plastic scintillators, liquid scintillators, and plastic scintillating and waveshifting fibers. Program goals are to develop faster and more efficient detection media for a variety of experimental applications
{"title":"Fast, long-wavelength scintillators and waveshifters","authors":"K. Andert, B. Baumbaugh, A. Brothers, A. David, H. Gunther, J. Gurrola, D. Karmgard, T. Madlem, J. Marchant, P. Mcgough, M. Mckenna, R. Ruchti, J. Thompson, M. Vigneault, L. Hernández, C. Hurlbut","doi":"10.1142/9789812773678_0064","DOIUrl":"https://doi.org/10.1142/9789812773678_0064","url":null,"abstract":"Studies are presented of new blue-green to red emitting scintillator and waveshifter materials for tracking and calorimetry applications for the detection of ionizing radiation. Materials include plastic scintillators, liquid scintillators, and plastic scintillating and waveshifting fibers. Program goals are to develop faster and more efficient detection media for a variety of experimental applications","PeriodicalId":105619,"journal":{"name":"IEEE Nuclear Science Symposium Conference Record, 2005","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123067506","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 : 2006-04-01DOI: 10.1109/NSSMIC.2005.1596210
V. Re, M. Bondioli, M. Bruinsma, S. Curry, D. Kirkby, J. Berryhill, S. Burke, D. Callahan, C. Campagnari, A. Cunha, B. Dahmes, D. Hale, S. Kyre, J. Richman, J. Stoner, W. Verkerke, T. Beck, A. Eisner, J. Kroseberg, W. Lockman, G. Nesom, A. Seiden, P. Spradlin, M. Wilson, L. Winstrom, C. Bozzi, G. Cibinetto, L. Piemontese, D. Brown, E. Charles, S. Dardin, F. Goozen, A. Gritsan, L. Kerth, G. Lynch, N. Roe, C. Chen, C. Lae, D. Roberts, G. Simi, A. Lazzaro, F. Palombo, H. Snoek, L. Ratti, C. Angelini, G. Batignani, S. Bettarini, F. Bosi, F. Bucci, G. Calderini, M. Carpinelli, M. Ceccanti, R. Cenci, F. Forti, M. Giorgi, A. Lusiani, P. Mammini, P. Manfredi, G. Marchiori, M. Mazur, M. Morganti, F. Morsani, N. Neri, E. Paoloni, A. Profeti, M. Rama, G. Rizzo, J. Walsh, P. Elmer, O. Long, A. Perazzo, P. Burchat, A. Edwards, S. Majewski, B. Petersen, M. Bona, F. Bianchi, D. Gamba, P. Trapani, M. Bomben, L. Bosisio, C. Cartaro, F. Cossutti, G. Della Ricca, S. Dittongo, L. Lanceri, L. Vitale, M. Datta, A. Mihályi
The silicon vertex tracker (SVT) of the BaBar experiment at PEP II is briefly described. It consists of five layers of double-sided AC-coupled silicon strip detectors, constituting the core of the BaBar tracking system. After six years of operation, some unexpected effects have appeared. In particular, a shift in the pedestal for the channels of the AToM readout chips that are most exposed to radiation has been observed. The behavior has been understood and reproduced in AToM chip irradiations with 1-GeV electrons at Elettra (Trieste) and the results of the studies are presented here. A second unexpected behavior has been detected, consisting of an anomalous increase in the bias leakage current for the modules in the outer layers. The effect is beam-related but not directly linked to radiation damage, as suggested by the fact that it is not present in the inner layers. The cause has been understood and the conclusions are presented here. The effect has been reproduced in a qualitative way in the laboratory. Over the next three years the luminosity is predicted to increase by a factor of three, leading to radiation and occupancy levels significantly exceeding the detector design. Estimates of future radiation doses and occupancies are shown together with the extrapolated detector performance and lifetime, in light of the new observations. Upgrade scenarios to deal with the increased luminosity and backgrounds are discussed.
{"title":"New effects observed in the BaBar silicon vertex tracker: interpretation and estimate of their impact on the future performance of the detector","authors":"V. Re, M. Bondioli, M. Bruinsma, S. Curry, D. Kirkby, J. Berryhill, S. Burke, D. Callahan, C. Campagnari, A. Cunha, B. Dahmes, D. Hale, S. Kyre, J. Richman, J. Stoner, W. Verkerke, T. Beck, A. Eisner, J. Kroseberg, W. Lockman, G. Nesom, A. Seiden, P. Spradlin, M. Wilson, L. Winstrom, C. Bozzi, G. Cibinetto, L. Piemontese, D. Brown, E. Charles, S. Dardin, F. Goozen, A. Gritsan, L. Kerth, G. Lynch, N. Roe, C. Chen, C. Lae, D. Roberts, G. Simi, A. Lazzaro, F. Palombo, H. Snoek, L. Ratti, C. Angelini, G. Batignani, S. Bettarini, F. Bosi, F. Bucci, G. Calderini, M. Carpinelli, M. Ceccanti, R. Cenci, F. Forti, M. Giorgi, A. Lusiani, P. Mammini, P. Manfredi, G. Marchiori, M. Mazur, M. Morganti, F. Morsani, N. Neri, E. Paoloni, A. Profeti, M. Rama, G. Rizzo, J. Walsh, P. Elmer, O. Long, A. Perazzo, P. Burchat, A. Edwards, S. Majewski, B. Petersen, M. Bona, F. Bianchi, D. Gamba, P. Trapani, M. Bomben, L. Bosisio, C. Cartaro, F. Cossutti, G. Della Ricca, S. Dittongo, L. Lanceri, L. Vitale, M. Datta, A. Mihályi","doi":"10.1109/NSSMIC.2005.1596210","DOIUrl":"https://doi.org/10.1109/NSSMIC.2005.1596210","url":null,"abstract":"The silicon vertex tracker (SVT) of the BaBar experiment at PEP II is briefly described. It consists of five layers of double-sided AC-coupled silicon strip detectors, constituting the core of the BaBar tracking system. After six years of operation, some unexpected effects have appeared. In particular, a shift in the pedestal for the channels of the AToM readout chips that are most exposed to radiation has been observed. The behavior has been understood and reproduced in AToM chip irradiations with 1-GeV electrons at Elettra (Trieste) and the results of the studies are presented here. A second unexpected behavior has been detected, consisting of an anomalous increase in the bias leakage current for the modules in the outer layers. The effect is beam-related but not directly linked to radiation damage, as suggested by the fact that it is not present in the inner layers. The cause has been understood and the conclusions are presented here. The effect has been reproduced in a qualitative way in the laboratory. Over the next three years the luminosity is predicted to increase by a factor of three, leading to radiation and occupancy levels significantly exceeding the detector design. Estimates of future radiation doses and occupancies are shown together with the extrapolated detector performance and lifetime, in light of the new observations. Upgrade scenarios to deal with the increased luminosity and backgrounds are discussed.","PeriodicalId":105619,"journal":{"name":"IEEE Nuclear Science Symposium Conference Record, 2005","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124079717","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 : 2006-04-01DOI: 10.1109/NSSMIC.2005.1596450
S. Derenzo, E. Bourret-Courchesne, F. James, M. Klintenberg, Y. Porter-Chapman, J. Wang, M. Weber
We describe a method for identifying semiconductor radiation detector materials based on the mobility of internally generated electrons and holes. It was designed for the early stages of exploration, when samples are not available as single crystals, but as crystalline powders. Samples are confined under pressure in an electric field and semiconductors are identified by an increase in d.c. conductivity during exposure to a high-intensity source of 60Co gamma rays. Using this method, we have determined that BiOI, PbIF, BiPbO2Cl, BiPbO2Br, BiPbO2I, Bi2GdO4Cl, Pb3O2I2, and Pb5O4I2 are semiconductors
{"title":"Identifying semiconductors by D.C. ionization conductivity","authors":"S. Derenzo, E. Bourret-Courchesne, F. James, M. Klintenberg, Y. Porter-Chapman, J. Wang, M. Weber","doi":"10.1109/NSSMIC.2005.1596450","DOIUrl":"https://doi.org/10.1109/NSSMIC.2005.1596450","url":null,"abstract":"We describe a method for identifying semiconductor radiation detector materials based on the mobility of internally generated electrons and holes. It was designed for the early stages of exploration, when samples are not available as single crystals, but as crystalline powders. Samples are confined under pressure in an electric field and semiconductors are identified by an increase in d.c. conductivity during exposure to a high-intensity source of <sup>60</sup>Co gamma rays. Using this method, we have determined that BiOI, PbIF, BiPbO<sub>2</sub>Cl, BiPbO<sub>2</sub>Br, BiPbO<sub>2</sub>I, Bi<sub>2</sub>GdO<sub>4</sub>Cl, Pb<sub>3</sub>O<sub>2</sub>I<sub>2</sub>, and Pb<sub>5</sub>O<sub>4</sub>I<sub>2</sub> are semiconductors","PeriodicalId":105619,"journal":{"name":"IEEE Nuclear Science Symposium Conference Record, 2005","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130171860","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 : 2006-01-19DOI: 10.1109/NSSMIC.2005.1596430
J. Bauer
The electromagnetic calorimeter at the BaBar detector, part of the asymmetric B factory at SLAC, measures photons in the energy range from 20 MeV to 8 GeV with high resolution. The current status of the calorimeter, now in its seventh year of operation, is being presented, as well as details on improvements made to the analysis code during the last years.
{"title":"The BaBar electromagnetic calorimeter: status and performance improvements","authors":"J. Bauer","doi":"10.1109/NSSMIC.2005.1596430","DOIUrl":"https://doi.org/10.1109/NSSMIC.2005.1596430","url":null,"abstract":"The electromagnetic calorimeter at the BaBar detector, part of the asymmetric B factory at SLAC, measures photons in the energy range from 20 MeV to 8 GeV with high resolution. The current status of the calorimeter, now in its seventh year of operation, is being presented, as well as details on improvements made to the analysis code during the last years.","PeriodicalId":105619,"journal":{"name":"IEEE Nuclear Science Symposium Conference Record, 2005","volume":"199 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116689269","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 : 2005-12-19DOI: 10.1142/9789812773678_0090
M. Gallas, A. Rimoldi, A. Dellacqua, A. Di Simone, A. Nairz, J. Boudreau, V. Tsulaia, D. Costanzo
The simulation program for the ATLAS experiment at CERN is currently in a full operational mode and integrated into the ATLAS's common analysis framework, ATHENA. The OO approach, based on GEANT4, and in use during the DC2 data challenge has been interfaced within ATHENA and to GEANT4 using the LCG dictionaries and Python scripting. The robustness of the application was proved during the DC2 data challenge. The Python interface has added the flexibility, modularity and interactivity that the simulation tool needs to tackle, in a common way, different full ATLAS simulations setups, test beams and cosmic ray studies. Generation, simulation and digitization steps were exercised for performance and robustness tests. The comparison with real data has been possible in the context of the ATLAS combined test beam (2004) and ongoing cosmic ray studies
{"title":"ATLAS detector simulation: status and outlook","authors":"M. Gallas, A. Rimoldi, A. Dellacqua, A. Di Simone, A. Nairz, J. Boudreau, V. Tsulaia, D. Costanzo","doi":"10.1142/9789812773678_0090","DOIUrl":"https://doi.org/10.1142/9789812773678_0090","url":null,"abstract":"The simulation program for the ATLAS experiment at CERN is currently in a full operational mode and integrated into the ATLAS's common analysis framework, ATHENA. The OO approach, based on GEANT4, and in use during the DC2 data challenge has been interfaced within ATHENA and to GEANT4 using the LCG dictionaries and Python scripting. The robustness of the application was proved during the DC2 data challenge. The Python interface has added the flexibility, modularity and interactivity that the simulation tool needs to tackle, in a common way, different full ATLAS simulations setups, test beams and cosmic ray studies. Generation, simulation and digitization steps were exercised for performance and robustness tests. The comparison with real data has been possible in the context of the ATLAS combined test beam (2004) and ongoing cosmic ray studies","PeriodicalId":105619,"journal":{"name":"IEEE Nuclear Science Symposium Conference Record, 2005","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131781867","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 : 2005-12-01DOI: 10.1109/NSSMIC.2005.1596662
S. Blinder, M. Camborde, K. Buckley, A. Rahmim, K. Cheng, T. Ruth, V. Sossi
The high resolution research tomograph (HRRT) is an octagonal design PET camera with 119,808 crystals arranged in a dual layer to determine the depth of interaction (DOI) and compensate for the parallax effect. The DOI discrimination is based on the identification of the layer in which the gamma interaction occurred using pulse shape discrimination. However the observed fractional crystal efficiency is count rate dependent, thus affecting the accuracy of the pulse shape discrimination. In this study we investigated the impact of the mismatch between the emission and the normalization scan count rate on image uniformity using phantom data when DOI correction was applied and when it was switched off. Count rate mismatch was found to manifest itself in form of streaking artifacts and high frequency non-uniformities with a star shape pattern in Fourier space. It was found to be enhanced when DOI correction was applied. In realistic scanning conditions assessed with non-human primate data the effect of count rate mismatch was found to be nearly negligible with DOI correction present or absent. Since DOI corrected data proved to be more sensitive to an emission/normalization count rate mismatch, the impact of DOI on resolution and biological measure obtained in realistic scanning conditions was further evaluated. With DOI determination, spatial resolution was improved by up to 7% in the outer part of the FoV where it was measured to be 2.9 /spl plusmn/ 0.2 mm (SPAN 3) and 3.3 /spl plusmn/ 0.2 mm (SPAN 9) and the biological parameters (binding potentials) extracted from the non-human primate study were improved by up to 5%. In summary this study shows a greater sensitivity to emission/normalization count rate mismatch in phantom studies when DOI correction is present. However much less sensitivity is observed in realistic data, while the resolution uniformity advantage due to DOI determination is still noticeable, not only in resolution measurement but also in the accuracy of the biological measures extracted from realistic scanning protocols.
高分辨率研究层析成像仪(HRRT)是一种八角形设计的PET相机，由119,808个晶体排列在双层中，以确定相互作用深度(DOI)并补偿视差效应。DOI识别是基于使用脉冲形状识别伽马相互作用发生的层的识别。然而，观察到的分数晶体效率依赖于计数率，从而影响了脉冲形状识别的准确性。在本研究中，我们研究了在应用DOI校正和关闭DOI校正时，使用幻影数据研究了发射和归一化扫描计数率之间的不匹配对图像均匀性的影响。发现计数率不匹配表现为条纹伪影和高频不均匀，在傅里叶空间中呈星形图案。应用DOI校正后，发现其增强。在非人类灵长类动物数据评估的现实扫描条件下，计数率不匹配的影响被发现几乎可以忽略不计，DOI校正存在或不存在。由于DOI校正后的数据对发射/归一化计数率失配更为敏感，因此我们进一步评估了DOI对实际扫描条件下获得的分辨率和生物测量的影响。通过DOI确定，FoV外部部分的空间分辨率提高了7%，测量结果为2.9 /spl plusmn/ 0.2 mm (SPAN 3)和3.3 /spl plusmn/ 0.2 mm (SPAN 9)，从非人灵长类动物研究中提取的生物学参数(结合电位)提高了5%。总之，本研究表明，当DOI校正存在时，幻影研究对发射/归一化计数率不匹配的敏感性更高。然而，在实际数据中观察到的灵敏度要低得多，而DOI确定所带来的分辨率均匀性优势仍然是显而易见的，不仅在分辨率测量方面，而且在从实际扫描方案中提取的生物测量的准确性方面。
{"title":"Influence of depth of interaction on spatial resolution and image quality for the HRRT","authors":"S. Blinder, M. Camborde, K. Buckley, A. Rahmim, K. Cheng, T. Ruth, V. Sossi","doi":"10.1109/NSSMIC.2005.1596662","DOIUrl":"https://doi.org/10.1109/NSSMIC.2005.1596662","url":null,"abstract":"The high resolution research tomograph (HRRT) is an octagonal design PET camera with 119,808 crystals arranged in a dual layer to determine the depth of interaction (DOI) and compensate for the parallax effect. The DOI discrimination is based on the identification of the layer in which the gamma interaction occurred using pulse shape discrimination. However the observed fractional crystal efficiency is count rate dependent, thus affecting the accuracy of the pulse shape discrimination. In this study we investigated the impact of the mismatch between the emission and the normalization scan count rate on image uniformity using phantom data when DOI correction was applied and when it was switched off. Count rate mismatch was found to manifest itself in form of streaking artifacts and high frequency non-uniformities with a star shape pattern in Fourier space. It was found to be enhanced when DOI correction was applied. In realistic scanning conditions assessed with non-human primate data the effect of count rate mismatch was found to be nearly negligible with DOI correction present or absent. Since DOI corrected data proved to be more sensitive to an emission/normalization count rate mismatch, the impact of DOI on resolution and biological measure obtained in realistic scanning conditions was further evaluated. With DOI determination, spatial resolution was improved by up to 7% in the outer part of the FoV where it was measured to be 2.9 /spl plusmn/ 0.2 mm (SPAN 3) and 3.3 /spl plusmn/ 0.2 mm (SPAN 9) and the biological parameters (binding potentials) extracted from the non-human primate study were improved by up to 5%. In summary this study shows a greater sensitivity to emission/normalization count rate mismatch in phantom studies when DOI correction is present. However much less sensitivity is observed in realistic data, while the resolution uniformity advantage due to DOI determination is still noticeable, not only in resolution measurement but also in the accuracy of the biological measures extracted from realistic scanning protocols.","PeriodicalId":105619,"journal":{"name":"IEEE Nuclear Science Symposium Conference Record, 2005","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125348223","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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