Pub Date : 2003-10-19DOI: 10.1109/NSSMIC.2003.1352620
Longxia Li, F. Lu, Chun Lee, Honglin Ding, Wangchang Zhang, W. Yao, R. James, R. Olsen, A. Burger, G. Wright, D. Rhiger, K. Shah, M. Squillante, L. Cirignano, Hadong Kim, V. Ivanov, P. Luke
Using modified vertical Bridgman and a seeded technique, 3-inch-diameter CdZnTe (CZT) ingots were successfully grown with 40% of the ingots having single-crystal volumes of over 300 cm/sup 3/, and 80% of the ingots with single-crystal volumes of over 100 cm/sup 3/. High-yield growth of CZT crystals with these dimensions enables the production of novel monolithic, multi-element detectors. Defects such as Cd-vacancies, indium dopant and impurities were studied systematically. The studies show that by appropriately reducing the Cd-vacancy and the Group III dopant, one can increase the /spl mu//spl tau/(e) and /spl mu//spl tau/(h) products. Furthermore, the indium doping and the purity of the CZT were found to limit the value of the /spl mu//spl tau/(e) product. The "best" purity source material coupled with an optimized indium doping concentration will produce /spl mu//spl tau/(e) products as high as 1.8x10/sup -2/ cm/sup 2//V (collimated and the "best" area), and the best /spl mu//spl tau/(h) is 7x10/sup -4/ cm/sup 2//V.
{"title":"Studies of Cd-vacancies, indium dopant and impurities in CdZnTe crystals (Zn = 10%)","authors":"Longxia Li, F. Lu, Chun Lee, Honglin Ding, Wangchang Zhang, W. Yao, R. James, R. Olsen, A. Burger, G. Wright, D. Rhiger, K. Shah, M. Squillante, L. Cirignano, Hadong Kim, V. Ivanov, P. Luke","doi":"10.1109/NSSMIC.2003.1352620","DOIUrl":"https://doi.org/10.1109/NSSMIC.2003.1352620","url":null,"abstract":"Using modified vertical Bridgman and a seeded technique, 3-inch-diameter CdZnTe (CZT) ingots were successfully grown with 40% of the ingots having single-crystal volumes of over 300 cm/sup 3/, and 80% of the ingots with single-crystal volumes of over 100 cm/sup 3/. High-yield growth of CZT crystals with these dimensions enables the production of novel monolithic, multi-element detectors. Defects such as Cd-vacancies, indium dopant and impurities were studied systematically. The studies show that by appropriately reducing the Cd-vacancy and the Group III dopant, one can increase the /spl mu//spl tau/(e) and /spl mu//spl tau/(h) products. Furthermore, the indium doping and the purity of the CZT were found to limit the value of the /spl mu//spl tau/(e) product. The \"best\" purity source material coupled with an optimized indium doping concentration will produce /spl mu//spl tau/(e) products as high as 1.8x10/sup -2/ cm/sup 2//V (collimated and the \"best\" area), and the best /spl mu//spl tau/(h) is 7x10/sup -4/ cm/sup 2//V.","PeriodicalId":186175,"journal":{"name":"2003 IEEE Nuclear Science Symposium. Conference Record (IEEE Cat. No.03CH37515)","volume":"20 3","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132968870","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 : 2003-10-19DOI: 10.1109/NSSMIC.2003.1352713
S. Zimmermann, C. Cernoch
The monitored drift tubes (MDTs) of the Atlas muon spectrometer have to sustain count rates up to 1500 Hz/cm and must be able to survive an accumulated charge of up to 0.6 C/cm during 10 years of operation. This paper presents results of aging studies carried out at the CERN Gamma Irradiation Facility GIF for the first time with a final Atlas muon chamber and a prototype of the gas recirculation system planned at LHC. A loss in pulse height was observed for MDTs under gas recirculation after an accumulated charge equivalent to only 1 year of LHC operation; the effect was traced to a silicone contamination from bad components in the gas recirculation system. Tubes operated with the classical one-pass, flushing mode did not show any evidence of aging, thus (re)validating the materials and components used in the MDT construction. Questions of long-term stability when recycling the major part of the operating gas could also be addressed by the measurements performed; results on this will also be discussed.
{"title":"Atlas monitored drift tube long-term stability and aging study performed for the first time with the gas-recirculation system planned for LHC","authors":"S. Zimmermann, C. Cernoch","doi":"10.1109/NSSMIC.2003.1352713","DOIUrl":"https://doi.org/10.1109/NSSMIC.2003.1352713","url":null,"abstract":"The monitored drift tubes (MDTs) of the Atlas muon spectrometer have to sustain count rates up to 1500 Hz/cm and must be able to survive an accumulated charge of up to 0.6 C/cm during 10 years of operation. This paper presents results of aging studies carried out at the CERN Gamma Irradiation Facility GIF for the first time with a final Atlas muon chamber and a prototype of the gas recirculation system planned at LHC. A loss in pulse height was observed for MDTs under gas recirculation after an accumulated charge equivalent to only 1 year of LHC operation; the effect was traced to a silicone contamination from bad components in the gas recirculation system. Tubes operated with the classical one-pass, flushing mode did not show any evidence of aging, thus (re)validating the materials and components used in the MDT construction. Questions of long-term stability when recycling the major part of the operating gas could also be addressed by the measurements performed; results on this will also be discussed.","PeriodicalId":186175,"journal":{"name":"2003 IEEE Nuclear Science Symposium. Conference Record (IEEE Cat. No.03CH37515)","volume":"110 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131951102","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 : 2003-10-19DOI: 10.1109/NSSMIC.2003.1352458
P. Koken, R. Manzke, M. Grass
Modern multislice CT systems with a fast rotating gantry are particularly suitable for cardiac volume imaging. Due to the cone angle, true 3D back-projection algorithms deliver superior image quality compared with 2D techniques. We propose a true cone-beam reconstruction algorithm making use of the maximum amount of the measured data in combination with retrospective cardiac gating. Results are presented on a patient data set, which has been acquired using a 16-slice CT system.
{"title":"Aperture weighted cardiac cone-beam reconstruction using retrospective ECG gating","authors":"P. Koken, R. Manzke, M. Grass","doi":"10.1109/NSSMIC.2003.1352458","DOIUrl":"https://doi.org/10.1109/NSSMIC.2003.1352458","url":null,"abstract":"Modern multislice CT systems with a fast rotating gantry are particularly suitable for cardiac volume imaging. Due to the cone angle, true 3D back-projection algorithms deliver superior image quality compared with 2D techniques. We propose a true cone-beam reconstruction algorithm making use of the maximum amount of the measured data in combination with retrospective cardiac gating. Results are presented on a patient data set, which has been acquired using a 16-slice CT system.","PeriodicalId":186175,"journal":{"name":"2003 IEEE Nuclear Science Symposium. Conference Record (IEEE Cat. No.03CH37515)","volume":"142 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131298746","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 : 2003-10-19DOI: 10.1109/NSSMIC.2003.1352390
S. Riboldi, J. Seidel, M. Green, J. Monaldo, J. Kakareka, T. Pohida
Pulse processing efficiency is among the most important parameters to maximize when designing effective systems for positron emission tomography (PET) applications. As the activity of the positron source increases, the attainable processing efficiency is often limited by the increased probability of pulse pileup. Various techniques have been proposed to read out position-sensitive multiwire or multianode photomultiplier tubes (PSPMTs) that trade resistance to pulse-pileup against the simplicity (and cost) of the readout method. Light spreading onto the detector surface also affects the choice of readout method for multianode tubes. Four methods for readout of signals are compared for the H8500 Hamamatsu multianode PSPMT. The first combines signals from the entire device surface; the second scheme implements readout of signals from four separate quadrants. The third scheme, proposed by Majewski et al., is based on row and column readout. We propose a fourth, and new, readout scheme based on a geometrical arrangement of overlapping square sectors. We show that this solution reduces pulse pileup yet requires a relatively small number of output signal lines to determine the energy and position of each scintillation event.
{"title":"Investigation of signal readout methods for the Hamamatsu R8500 flat panel PSPMT","authors":"S. Riboldi, J. Seidel, M. Green, J. Monaldo, J. Kakareka, T. Pohida","doi":"10.1109/NSSMIC.2003.1352390","DOIUrl":"https://doi.org/10.1109/NSSMIC.2003.1352390","url":null,"abstract":"Pulse processing efficiency is among the most important parameters to maximize when designing effective systems for positron emission tomography (PET) applications. As the activity of the positron source increases, the attainable processing efficiency is often limited by the increased probability of pulse pileup. Various techniques have been proposed to read out position-sensitive multiwire or multianode photomultiplier tubes (PSPMTs) that trade resistance to pulse-pileup against the simplicity (and cost) of the readout method. Light spreading onto the detector surface also affects the choice of readout method for multianode tubes. Four methods for readout of signals are compared for the H8500 Hamamatsu multianode PSPMT. The first combines signals from the entire device surface; the second scheme implements readout of signals from four separate quadrants. The third scheme, proposed by Majewski et al., is based on row and column readout. We propose a fourth, and new, readout scheme based on a geometrical arrangement of overlapping square sectors. We show that this solution reduces pulse pileup yet requires a relatively small number of output signal lines to determine the energy and position of each scintillation event.","PeriodicalId":186175,"journal":{"name":"2003 IEEE Nuclear Science Symposium. Conference Record (IEEE Cat. No.03CH37515)","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125449012","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 : 2003-10-19DOI: 10.1109/NSSMIC.2003.1352398
E. Yoshida, Y. Kimura, K. Kitamura, H. Murayama
A depth of interaction (DOI) detector is developed for the next generation of PET scanners. The detector unit consists of 8/spl times/8 crystal blocks with 4 layers of 2/spl times/2 Gd/sub 2/SiO/sub 5/:Ce (GSO) arrays coupled to a 52 mm square position sensitive photomultiplier tube (PS-PMT). Each scintillation event is mapped in a two-dimensional (2D) distribution through the relative ratio of the output signals of the PS-PMT. To facilitate high spatial resolution imaging, accurate crystal identification is needed. A statistical model based on the approach of a mixture Gaussian model (MGM) is introduced for crystal identification. In the MGM, a cluster center and range attributed to individual peaks in the 2D distribution are defined. The MGM method is applied two times, once for the cluster centers and once for determination of the range. These results are used to generate a Look-Up-Table (LUT). This method successfully identifies 288 crystal elements composing 36 crystal blocks.
{"title":"Calibration procedure for a DOI detector of high resolution PET through mixture Gaussian model","authors":"E. Yoshida, Y. Kimura, K. Kitamura, H. Murayama","doi":"10.1109/NSSMIC.2003.1352398","DOIUrl":"https://doi.org/10.1109/NSSMIC.2003.1352398","url":null,"abstract":"A depth of interaction (DOI) detector is developed for the next generation of PET scanners. The detector unit consists of 8/spl times/8 crystal blocks with 4 layers of 2/spl times/2 Gd/sub 2/SiO/sub 5/:Ce (GSO) arrays coupled to a 52 mm square position sensitive photomultiplier tube (PS-PMT). Each scintillation event is mapped in a two-dimensional (2D) distribution through the relative ratio of the output signals of the PS-PMT. To facilitate high spatial resolution imaging, accurate crystal identification is needed. A statistical model based on the approach of a mixture Gaussian model (MGM) is introduced for crystal identification. In the MGM, a cluster center and range attributed to individual peaks in the 2D distribution are defined. The MGM method is applied two times, once for the cluster centers and once for determination of the range. These results are used to generate a Look-Up-Table (LUT). This method successfully identifies 288 crystal elements composing 36 crystal blocks.","PeriodicalId":186175,"journal":{"name":"2003 IEEE Nuclear Science Symposium. Conference Record (IEEE Cat. No.03CH37515)","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122212304","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 : 2003-10-19DOI: 10.1109/NSSMIC.2003.1352446
K. Dixon, L.N. Baldwin, B. Coquinco, E. Vandervoort, A. Fung, A. Celler
In order to determine the size of myocardial perfusion infarcts in clinical SPECT images, we have developed a software package iQuant that eliminates the need for a normal-heart database - a problem that exists in commercial products. Details of the iQuant method are presented in this paper together with results from preliminary tests of accuracy and reproducibility. iQuant uses different count thresholds to define viable myocardial tissue and to provide a rough outline of the complete myocardium. This outline together with the visible thickness of the viable myocardium is used by the operator as a guide to determine the location and size of infarcted tissue. Using noiseless data iQuant is shown to be accurate to within 5%; with more clinically realistic simulated data the measured accuracy is 14%. When testing reproducibility, independent operators consistently produced results within 10% of the truth. Clinical experience was shown to be an important factor in the reproducible accuracy of each individual observer. Measurements to date only involve infarcts considered clinically small, but further work is planned to investigate the reliability of this method over a large range of infarct sizes and locations. Initial analysis shows the iQuant software to be an objective, robust and versatile tool suitable for the determination of myocardial perfusion infarct size in the clinical research environment. Its elimination of the need for a normal-heart database is its main advantages over current, commercially availably software.
{"title":"A robust and versatile method for the quantification of myocardial infarct size","authors":"K. Dixon, L.N. Baldwin, B. Coquinco, E. Vandervoort, A. Fung, A. Celler","doi":"10.1109/NSSMIC.2003.1352446","DOIUrl":"https://doi.org/10.1109/NSSMIC.2003.1352446","url":null,"abstract":"In order to determine the size of myocardial perfusion infarcts in clinical SPECT images, we have developed a software package iQuant that eliminates the need for a normal-heart database - a problem that exists in commercial products. Details of the iQuant method are presented in this paper together with results from preliminary tests of accuracy and reproducibility. iQuant uses different count thresholds to define viable myocardial tissue and to provide a rough outline of the complete myocardium. This outline together with the visible thickness of the viable myocardium is used by the operator as a guide to determine the location and size of infarcted tissue. Using noiseless data iQuant is shown to be accurate to within 5%; with more clinically realistic simulated data the measured accuracy is 14%. When testing reproducibility, independent operators consistently produced results within 10% of the truth. Clinical experience was shown to be an important factor in the reproducible accuracy of each individual observer. Measurements to date only involve infarcts considered clinically small, but further work is planned to investigate the reliability of this method over a large range of infarct sizes and locations. Initial analysis shows the iQuant software to be an objective, robust and versatile tool suitable for the determination of myocardial perfusion infarct size in the clinical research environment. Its elimination of the need for a normal-heart database is its main advantages over current, commercially availably software.","PeriodicalId":186175,"journal":{"name":"2003 IEEE Nuclear Science Symposium. Conference Record (IEEE Cat. No.03CH37515)","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120967135","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 : 2003-10-19DOI: 10.1109/NSSMIC.2003.1352460
T. Li, Z. Liang, K. Mueller, J. Heimann, L. Johnson, H. Sadrozinski, A. Seiden, David C Williams, L. Zhang, S. Peggs, T. Satogata, V. Bashkirov, R. Schulte
Advantages of proton computed tomography (pCT) have been recognized in the past. However, the quality of a pCT image may be limited due to the stochastic nature of the proton path inside the object. In this work, we report a preliminary study on reconstruction of pCT image with improved path estimation. A set of Monte Carlo simulations was carried out with the GEANT4 program, and reconstructed by filtered backprojection method. Simulations with different density contrast settings were compared, and spatial resolution around 0.5 mm for the highest contrast phantom was achieved, which is comparable to that of X-ray CT image. Further improvement by utilizing the statistical properties of proton transport is expected and is under progress.
{"title":"Reconstruction for proton computed tomography: a Monte Carlo study","authors":"T. Li, Z. Liang, K. Mueller, J. Heimann, L. Johnson, H. Sadrozinski, A. Seiden, David C Williams, L. Zhang, S. Peggs, T. Satogata, V. Bashkirov, R. Schulte","doi":"10.1109/NSSMIC.2003.1352460","DOIUrl":"https://doi.org/10.1109/NSSMIC.2003.1352460","url":null,"abstract":"Advantages of proton computed tomography (pCT) have been recognized in the past. However, the quality of a pCT image may be limited due to the stochastic nature of the proton path inside the object. In this work, we report a preliminary study on reconstruction of pCT image with improved path estimation. A set of Monte Carlo simulations was carried out with the GEANT4 program, and reconstructed by filtered backprojection method. Simulations with different density contrast settings were compared, and spatial resolution around 0.5 mm for the highest contrast phantom was achieved, which is comparable to that of X-ray CT image. Further improvement by utilizing the statistical properties of proton transport is expected and is under progress.","PeriodicalId":186175,"journal":{"name":"2003 IEEE Nuclear Science Symposium. Conference Record (IEEE Cat. No.03CH37515)","volume":"84 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121249109","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 : 2003-10-19DOI: 10.1109/NSSMIC.2003.1352707
G. Royle, R. Speller, P. Sellin, J. Gabathuse, W. Ghoggali
Work is underway to produce a clinical imaging system, based upon the Compton camera principle, to image positron emitters. The system has been designed by computer simulation to have a spatial resolution <1 cm at the patient and have good efficiency at 511 keV. An attempt has been made to make the camera reasonably portable. The camera was constructed by ORTEC. Controlling electronics based upon GRT4 electronics boards (Daresbury, UK) are employed. The camera comprises two pixellated germanium detector planes housed 9.6 cm apart in the same vacuum housing. The scattering detector is a pixellated germanium ring with an outer diameter of 10 cm, an inner diameter of 6 cm and a thickness of 0.4 cm. A total of 152 4/spl times/4 mm/sup 2/ pixels are distributed in 8 blocks around the ring. The absorbing detector is a pixellated germanium cylinder with a diameter of 2.8 cm and a thickness of 1 cm. A 5/spl times/5 block of 4/spl times/4 mm/sup 2/ pixels are implanted in the absorbing detector. Pulse timing information and induced charge in surrounding pixels is used to improve the intrinsic spatial resolution of the detectors to an expected value of /spl sim/1 mm. A mean energy resolution of 1.9 keV at 122 keV has been achieved, with a 0.2 keV standard deviation across the pixels. This paper will summarise the results to date and present the current state of camera developments.
{"title":"Development of a pixellated germanium Compton camera for nuclear medicine","authors":"G. Royle, R. Speller, P. Sellin, J. Gabathuse, W. Ghoggali","doi":"10.1109/NSSMIC.2003.1352707","DOIUrl":"https://doi.org/10.1109/NSSMIC.2003.1352707","url":null,"abstract":"Work is underway to produce a clinical imaging system, based upon the Compton camera principle, to image positron emitters. The system has been designed by computer simulation to have a spatial resolution <1 cm at the patient and have good efficiency at 511 keV. An attempt has been made to make the camera reasonably portable. The camera was constructed by ORTEC. Controlling electronics based upon GRT4 electronics boards (Daresbury, UK) are employed. The camera comprises two pixellated germanium detector planes housed 9.6 cm apart in the same vacuum housing. The scattering detector is a pixellated germanium ring with an outer diameter of 10 cm, an inner diameter of 6 cm and a thickness of 0.4 cm. A total of 152 4/spl times/4 mm/sup 2/ pixels are distributed in 8 blocks around the ring. The absorbing detector is a pixellated germanium cylinder with a diameter of 2.8 cm and a thickness of 1 cm. A 5/spl times/5 block of 4/spl times/4 mm/sup 2/ pixels are implanted in the absorbing detector. Pulse timing information and induced charge in surrounding pixels is used to improve the intrinsic spatial resolution of the detectors to an expected value of /spl sim/1 mm. A mean energy resolution of 1.9 keV at 122 keV has been achieved, with a 0.2 keV standard deviation across the pixels. This paper will summarise the results to date and present the current state of camera developments.","PeriodicalId":186175,"journal":{"name":"2003 IEEE Nuclear Science Symposium. Conference Record (IEEE Cat. No.03CH37515)","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122851618","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 : 2003-10-19DOI: 10.1109/NSSMIC.2003.1352414
K. Lee, Paul Kinahan, J. Fessler, R. Miyaoka, T. Lewellen
We present a pragmatic approach to image reconstruction for data from the MiCES fully-3D mouse imaging PET scanner under construction at the University of Washington. Our approach is modeled on fully-3D image reconstruction used in clinical PET scanners, which is based on Fourier rebinning (FORE) followed by 2D iterative image reconstruction. The use of iterative methods allows modeling the effects of statistical noise and attenuation etc., while FORE accelerates the reconstruction process by reducing the fully-3D data to a stacked set of independent 2D sinograms. Preliminary investigations have indicated that nonstationary detector point-spread response effects, which are ignored for clinical imaging, significantly impact image quality for the MiCES scanner geometry. To model the effect of nonstationary detector point spread response, we have added a factorized system matrix to the ASPIRE reconstruction library. The current implementation uses FORE+AWOSEM followed by postreconstruction 3D Gaussian smoothing. The results indicate that the proposed approach produces a dramatic improvement in resolution without undue increases in noise.
{"title":"Pragmatic image reconstruction for the MiCES Fully-3D mouse imaging PET scanner","authors":"K. Lee, Paul Kinahan, J. Fessler, R. Miyaoka, T. Lewellen","doi":"10.1109/NSSMIC.2003.1352414","DOIUrl":"https://doi.org/10.1109/NSSMIC.2003.1352414","url":null,"abstract":"We present a pragmatic approach to image reconstruction for data from the MiCES fully-3D mouse imaging PET scanner under construction at the University of Washington. Our approach is modeled on fully-3D image reconstruction used in clinical PET scanners, which is based on Fourier rebinning (FORE) followed by 2D iterative image reconstruction. The use of iterative methods allows modeling the effects of statistical noise and attenuation etc., while FORE accelerates the reconstruction process by reducing the fully-3D data to a stacked set of independent 2D sinograms. Preliminary investigations have indicated that nonstationary detector point-spread response effects, which are ignored for clinical imaging, significantly impact image quality for the MiCES scanner geometry. To model the effect of nonstationary detector point spread response, we have added a factorized system matrix to the ASPIRE reconstruction library. The current implementation uses FORE+AWOSEM followed by postreconstruction 3D Gaussian smoothing. The results indicate that the proposed approach produces a dramatic improvement in resolution without undue increases in noise.","PeriodicalId":186175,"journal":{"name":"2003 IEEE Nuclear Science Symposium. Conference Record (IEEE Cat. No.03CH37515)","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121644124","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 : 2003-10-19DOI: 10.1109/NSSMIC.2003.1352379
K. Thielemans, S. Mustafovic, L. Schnorr
We discuss a motion correction scheme for rigid body motion in PET if the movement is known. Several groups have previously proposed a 2 stage process for motion correction: acquiring the data in list-mode and realigning the events according to the known motion before binning them into a sinogram, followed by reconstruction of the sinogram. However, motion correction of the sinogram data can result in parts of the sinogram not being filled for the full duration of the time frame. This results in image artefacts. We suggest ways to remove these artefacts by either reprojecting data or by determining scale factors for the partially measured parts of the sinogram, or a combination of both. We test this on simulations, phantom data and one patient study.
{"title":"Image reconstruction of motion corrected sinograms","authors":"K. Thielemans, S. Mustafovic, L. Schnorr","doi":"10.1109/NSSMIC.2003.1352379","DOIUrl":"https://doi.org/10.1109/NSSMIC.2003.1352379","url":null,"abstract":"We discuss a motion correction scheme for rigid body motion in PET if the movement is known. Several groups have previously proposed a 2 stage process for motion correction: acquiring the data in list-mode and realigning the events according to the known motion before binning them into a sinogram, followed by reconstruction of the sinogram. However, motion correction of the sinogram data can result in parts of the sinogram not being filled for the full duration of the time frame. This results in image artefacts. We suggest ways to remove these artefacts by either reprojecting data or by determining scale factors for the partially measured parts of the sinogram, or a combination of both. We test this on simulations, phantom data and one patient study.","PeriodicalId":186175,"journal":{"name":"2003 IEEE Nuclear Science Symposium. Conference Record (IEEE Cat. No.03CH37515)","volume":"54 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127685479","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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