Pub Date : 2005-12-01DOI: 10.1109/NSSMIC.2005.1596555
D. Satoh, T. Sato, A. Endo, N. Matsufuji, S. Sato, M. Takada, K. Ishibashi
In order to investigate the relationship between kinetic energy of charged particles and light output of liquid organic scintillator, response functions for proton, deuteron, triton, /sup 3/He nucleus and alpha particle have been measured at heavy-ion medical accelerator in Chiba (HIMAC) of National Institute of Radiological Sciences (NIRS). The charged particles were generated by 400 MeV/u C ion bombardment with a thick graphite target. Kinetic energies were determined by time-of-flight (TOF) technique. Energy loss during their flight was calculated by PHITS code and taken into account at energy-correction. Light output for proton was also measured using mono-energy proton beam of 100 and 160 MeV supplied by accelerator. Kinetic energy of proton beam was changed by inserting Al plates onto beam axis as an energy absorber. The experimental results gave a new database of light output.
{"title":"Study of light output and response function of liquid organic scintillator for high-energy neutron spectrometry","authors":"D. Satoh, T. Sato, A. Endo, N. Matsufuji, S. Sato, M. Takada, K. Ishibashi","doi":"10.1109/NSSMIC.2005.1596555","DOIUrl":"https://doi.org/10.1109/NSSMIC.2005.1596555","url":null,"abstract":"In order to investigate the relationship between kinetic energy of charged particles and light output of liquid organic scintillator, response functions for proton, deuteron, triton, /sup 3/He nucleus and alpha particle have been measured at heavy-ion medical accelerator in Chiba (HIMAC) of National Institute of Radiological Sciences (NIRS). The charged particles were generated by 400 MeV/u C ion bombardment with a thick graphite target. Kinetic energies were determined by time-of-flight (TOF) technique. Energy loss during their flight was calculated by PHITS code and taken into account at energy-correction. Light output for proton was also measured using mono-energy proton beam of 100 and 160 MeV supplied by accelerator. Kinetic energy of proton beam was changed by inserting Al plates onto beam axis as an energy absorber. The experimental results gave a new database of light output.","PeriodicalId":105619,"journal":{"name":"IEEE Nuclear Science Symposium Conference Record, 2005","volume":"87 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":"123619109","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.2005.1596712
D. Xia, E. Sidky, Lifeng Yu, Y. Zou, Xiaochuan Pan
In C-arm CT, the actual trajectory executed by the X-ray source may deviate from the designed scan due to mechanical error. Without taking into account this deviation, artifacts will appear in the reconstructed image. In this work, we propose to use the recently developed backprojection filtration (BPF) algorithm, which can accommodate general trajectories, to incorporate the deviation of the source trajectory. The preliminary studies demonstrate that this algorithm provides the exact image reconstruction in the case that the deviation of the source trajectory from the ideal trajectory can be measured.
{"title":"Exact ROI image reconstruction with perturbed source trajectories in C-arm CT","authors":"D. Xia, E. Sidky, Lifeng Yu, Y. Zou, Xiaochuan Pan","doi":"10.1109/NSSMIC.2005.1596712","DOIUrl":"https://doi.org/10.1109/NSSMIC.2005.1596712","url":null,"abstract":"In C-arm CT, the actual trajectory executed by the X-ray source may deviate from the designed scan due to mechanical error. Without taking into account this deviation, artifacts will appear in the reconstructed image. In this work, we propose to use the recently developed backprojection filtration (BPF) algorithm, which can accommodate general trajectories, to incorporate the deviation of the source trajectory. The preliminary studies demonstrate that this algorithm provides the exact image reconstruction in the case that the deviation of the source trajectory from the ideal trajectory can be measured.","PeriodicalId":105619,"journal":{"name":"IEEE Nuclear Science Symposium Conference Record, 2005","volume":"6 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":"130029076","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.2005.1596966
P. Ojala, A. Bousselham, L. Eriksson, A. Brahme, C. Bohm
This paper reports the characterization and comparison of different sensor configurations for monolithic scintillation crystals via the calculation of a figure of a merit based on statistical (Fischer) information. The optimal precision of maximum likelihood determinations of interaction positions, i.e. where annihilation photons are absorbed in a monolithic (LSO) crystal, is approximated throughout a crystal block via Fischer information (related to the width of the maximum likelihood distribution) evaluated at a grid of points. Realistic positions and thus realistic distributions of points of interaction are estimated by applying a maximum likelihood algorithm to Monte Carlo data. The algorithm was based on pattern recognition using a Monte Carlo generated lookup table and the least square method. The precision of this method is compared with the optimal (Cramer-Rao) limit for selected points
{"title":"Influence of sensor arrangements and scintillator crystal properties on the 3D precision of monolithic scintillation detectors in PET","authors":"P. Ojala, A. Bousselham, L. Eriksson, A. Brahme, C. Bohm","doi":"10.1109/NSSMIC.2005.1596966","DOIUrl":"https://doi.org/10.1109/NSSMIC.2005.1596966","url":null,"abstract":"This paper reports the characterization and comparison of different sensor configurations for monolithic scintillation crystals via the calculation of a figure of a merit based on statistical (Fischer) information. The optimal precision of maximum likelihood determinations of interaction positions, i.e. where annihilation photons are absorbed in a monolithic (LSO) crystal, is approximated throughout a crystal block via Fischer information (related to the width of the maximum likelihood distribution) evaluated at a grid of points. Realistic positions and thus realistic distributions of points of interaction are estimated by applying a maximum likelihood algorithm to Monte Carlo data. The algorithm was based on pattern recognition using a Monte Carlo generated lookup table and the least square method. The precision of this method is compared with the optimal (Cramer-Rao) limit for selected points","PeriodicalId":105619,"journal":{"name":"IEEE Nuclear Science Symposium Conference Record, 2005","volume":"10 2 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":"129714099","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.2005.1596786
M. King, Lifeng Yu, D. Xia, Xiaochuan Pan, M. Giger
In order to evaluate the potential of using the backprojection filtration (BPF) algorithm for reconstructing images from motion-contaminated data, simulation studies were conducted with three virtual phantoms. The first was a uniform elliptical phantom, which underwent rotational motion during half of its temporal cycle. The second was a normal-sized modified FORBILD phantom with a dynamic insert undergoing contractile motion during 65% of its temporal cycle. This phantom was expanded to form a third phantom, whose portions extended beyond the field-of-view (FOV). For the elliptical phantom, the BPF algorithm was able to obtain an exact reconstruction of a region-of-interest (ROI) covering a portion of the ellipse, whereas the fanbeam filtered backprojection (FFBP) algorithm could not. For the normal-sized phantom, nine full-scan data sets were acquired with percents of motion-contaminated data PMCDs ranging from 17.5% to 100%. For each data set, the mean absolute difference MAD, root mean square error RMS, and correlation CORR metrics were used to assess the differences between a defined ROI reconstructed from motion-contaminated data from the same ROI reconstructed from motion-free data. The BPF algorithm using a reduced-scan interval was able to produce better MAD, RMS, and CORR metrics than both FFBP and BPF algorithms using the same short-scan interval over all PMCDs. For the expanded phantom, the presence of truncations in the data sets did not affect the overall trends of the three metrics in BPF reconstructions of eight data sets with PMCDs ranging from 15% to 100%.
{"title":"ROI reconstruction of motion-contaminated data with a backprojection filtration algorithm","authors":"M. King, Lifeng Yu, D. Xia, Xiaochuan Pan, M. Giger","doi":"10.1109/NSSMIC.2005.1596786","DOIUrl":"https://doi.org/10.1109/NSSMIC.2005.1596786","url":null,"abstract":"In order to evaluate the potential of using the backprojection filtration (BPF) algorithm for reconstructing images from motion-contaminated data, simulation studies were conducted with three virtual phantoms. The first was a uniform elliptical phantom, which underwent rotational motion during half of its temporal cycle. The second was a normal-sized modified FORBILD phantom with a dynamic insert undergoing contractile motion during 65% of its temporal cycle. This phantom was expanded to form a third phantom, whose portions extended beyond the field-of-view (FOV). For the elliptical phantom, the BPF algorithm was able to obtain an exact reconstruction of a region-of-interest (ROI) covering a portion of the ellipse, whereas the fanbeam filtered backprojection (FFBP) algorithm could not. For the normal-sized phantom, nine full-scan data sets were acquired with percents of motion-contaminated data PMCDs ranging from 17.5% to 100%. For each data set, the mean absolute difference MAD, root mean square error RMS, and correlation CORR metrics were used to assess the differences between a defined ROI reconstructed from motion-contaminated data from the same ROI reconstructed from motion-free data. The BPF algorithm using a reduced-scan interval was able to produce better MAD, RMS, and CORR metrics than both FFBP and BPF algorithms using the same short-scan interval over all PMCDs. For the expanded phantom, the presence of truncations in the data sets did not affect the overall trends of the three metrics in BPF reconstructions of eight data sets with PMCDs ranging from 15% to 100%.","PeriodicalId":105619,"journal":{"name":"IEEE Nuclear Science Symposium Conference Record, 2005","volume":"260 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":"132755469","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.2005.1596579
M. Despeisse, D. Moraes, G. Anelli, P. Jarron, J. Kapłon, R. Rusack, S. Saramad, N. Wyrsch
The performance and limitations of a novel detector technology based on the deposition of a thin-film sensor on top of processed integrated circuits have been studied. Hydrogenated amorphous silicon (a-Si:H) films have been deposited on top of CMOS circuits developed for these studies and the resulting "thin-film on ASIC" (TFA) detectors are presented. The leakage current of the a-Si:H sensor at high reverse biases turns out to be an important parameter limiting the performance of a TFA detector. Its detailed study and the pixel segmentation of the detector are presented. High internal electric fields (in the order of 10/sup 4/-10/sup 5/ V/cm) can be built in the a-Si:H sensor and overcome the low mobility of electrons and holes in a-Si:H. Signal induction by generated carrier motion and speed in the a-Si:H sensor have been studied with a 660 nm pulsed laser on a TFA detector based on an ASIC integrating 5 ns peaking time pre-amplifiers. The measurement set-up also permits to study the depletion of the sensor and results are presented. Finally, direct detection of 5.9 keV X-rays with TFA detectors based on an ASIC integrating low noise pre-amplifiers (27 e/sup -/ r.m.s.) are shown.
{"title":"Hydrogenated amorphous silicon sensors based on thin film on ASIC technology","authors":"M. Despeisse, D. Moraes, G. Anelli, P. Jarron, J. Kapłon, R. Rusack, S. Saramad, N. Wyrsch","doi":"10.1109/NSSMIC.2005.1596579","DOIUrl":"https://doi.org/10.1109/NSSMIC.2005.1596579","url":null,"abstract":"The performance and limitations of a novel detector technology based on the deposition of a thin-film sensor on top of processed integrated circuits have been studied. Hydrogenated amorphous silicon (a-Si:H) films have been deposited on top of CMOS circuits developed for these studies and the resulting \"thin-film on ASIC\" (TFA) detectors are presented. The leakage current of the a-Si:H sensor at high reverse biases turns out to be an important parameter limiting the performance of a TFA detector. Its detailed study and the pixel segmentation of the detector are presented. High internal electric fields (in the order of 10/sup 4/-10/sup 5/ V/cm) can be built in the a-Si:H sensor and overcome the low mobility of electrons and holes in a-Si:H. Signal induction by generated carrier motion and speed in the a-Si:H sensor have been studied with a 660 nm pulsed laser on a TFA detector based on an ASIC integrating 5 ns peaking time pre-amplifiers. The measurement set-up also permits to study the depletion of the sensor and results are presented. Finally, direct detection of 5.9 keV X-rays with TFA detectors based on an ASIC integrating low noise pre-amplifiers (27 e/sup -/ r.m.s.) are shown.","PeriodicalId":105619,"journal":{"name":"IEEE Nuclear Science Symposium Conference Record, 2005","volume":"38 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":"132505822","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.2005.1596893
Lifeng Yu, D. Xia, Y. Zou, E. Sidky, Xiaochuan Pan, C. Pelizzari
We propose an alternative backprojection-filtration(BPF)-based reconstruction algorithm for fan-beam CT, which reconstructs images by first converting the fan-beam data to fan-parallel-beam data and then using a modified parallel-beam BPF algorithm to obtain the reconstruction. This proposed algorithm retains the properties of the original fan-beam BPF algorithm in that it can reconstruct exact region of interest (ROI) images from truncated data and/or super-short-scan data. The major advantage of this algorithm is its improved noise properties because of the elimination of the spatially-variant weighting factor. In addition, the proposed algorithm is computationally more efficient
{"title":"A rebinning-type backprojection-filtration algorithm for region of interest reconstruction in fan-beam CT with improved noise properties","authors":"Lifeng Yu, D. Xia, Y. Zou, E. Sidky, Xiaochuan Pan, C. Pelizzari","doi":"10.1109/NSSMIC.2005.1596893","DOIUrl":"https://doi.org/10.1109/NSSMIC.2005.1596893","url":null,"abstract":"We propose an alternative backprojection-filtration(BPF)-based reconstruction algorithm for fan-beam CT, which reconstructs images by first converting the fan-beam data to fan-parallel-beam data and then using a modified parallel-beam BPF algorithm to obtain the reconstruction. This proposed algorithm retains the properties of the original fan-beam BPF algorithm in that it can reconstruct exact region of interest (ROI) images from truncated data and/or super-short-scan data. The major advantage of this algorithm is its improved noise properties because of the elimination of the spatially-variant weighting factor. In addition, the proposed algorithm is computationally more efficient","PeriodicalId":105619,"journal":{"name":"IEEE Nuclear Science Symposium Conference Record, 2005","volume":"2 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":"132088326","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.2005.1596735
Z. Burbar, C. Michel, D. Towsend, B. Jakoby, M. Sibomana, F. Kehren, S. Tolbert, J. Reed, K. Hubner, M. Abidi
Continuous whole-body PET scanning, continuous bed motion (CBM) acquisition has a number of advantages over the traditional step-and-shoot (SS) mode. Strengths of CBM include a uniform axial signal-to-noise ratio, continuous sampling in the axial direction that reduces resolution artifacts, reduction of noise from detector normalization, and reduction of sensitivity to small patient movements. This work highlights the acquisition and data handling methodology that was implemented for a series of phantoms and over 40 patient studies acquired on a high resolution, 16-slice LSO combined PET/CT scanner (CPS Innovations, Knoxville, TN). CBM data were acquired in 32-bit listmode with the bed moving at a constant speed of typically 0.6 mm/s to match the acquisition time per plane of the SS mode. CBM data were processed using the novel, virtual scanner concept that can be applied to a scanner of any axial length. For the high resolution scanner, the LSO PET detectors are arranged in a truncated spherical geometry and therefore normalization and geometrical corrections are applied on an event-by-event basis during histogramming of the 32-bit listmode data. Scatter correction is calculated on the entire image volume, in contrast to the SS mode where scatter is estimated for each bed position. The final 3D data set was reconstructed using ordinary Poisson OSEM3D. This paper will present results from phantom studies and compare clinical patient scans acquired in both SS and CBM modes
{"title":"Continuous bed motion data processing for a resolution LSO PET/CT scanner","authors":"Z. Burbar, C. Michel, D. Towsend, B. Jakoby, M. Sibomana, F. Kehren, S. Tolbert, J. Reed, K. Hubner, M. Abidi","doi":"10.1109/NSSMIC.2005.1596735","DOIUrl":"https://doi.org/10.1109/NSSMIC.2005.1596735","url":null,"abstract":"Continuous whole-body PET scanning, continuous bed motion (CBM) acquisition has a number of advantages over the traditional step-and-shoot (SS) mode. Strengths of CBM include a uniform axial signal-to-noise ratio, continuous sampling in the axial direction that reduces resolution artifacts, reduction of noise from detector normalization, and reduction of sensitivity to small patient movements. This work highlights the acquisition and data handling methodology that was implemented for a series of phantoms and over 40 patient studies acquired on a high resolution, 16-slice LSO combined PET/CT scanner (CPS Innovations, Knoxville, TN). CBM data were acquired in 32-bit listmode with the bed moving at a constant speed of typically 0.6 mm/s to match the acquisition time per plane of the SS mode. CBM data were processed using the novel, virtual scanner concept that can be applied to a scanner of any axial length. For the high resolution scanner, the LSO PET detectors are arranged in a truncated spherical geometry and therefore normalization and geometrical corrections are applied on an event-by-event basis during histogramming of the 32-bit listmode data. Scatter correction is calculated on the entire image volume, in contrast to the SS mode where scatter is estimated for each bed position. The final 3D data set was reconstructed using ordinary Poisson OSEM3D. This paper will present results from phantom studies and compare clinical patient scans acquired in both SS and CBM modes","PeriodicalId":105619,"journal":{"name":"IEEE Nuclear Science Symposium Conference Record, 2005","volume":"16 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":"114288737","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.2005.1596919
F. Garibaldi, R. Accorsi, M. Cinti, E. Cisbani, S. Colilli, F. Cusanno, R. Fratoni, F. Giuliani, M. Gricia, R. Lanza, S. Meo, M. Lucentini, S. Majewski, R. Pani, R. Pellegrini, F. Santavenere, B. M. W. Tsui
Good spatial resolution and high sensitivity are required for detectors to be used for most of the bio-medical research and application (small animal imaging, detection of small tumors). In this paper we report on parameter optimization of single photon gamma rays detectors. Simulations and measurements were performed for designing and building detectors for early detection of small tumors in breast and in small animal imaging. Critical parameters are: contrast and signal to noise ratio (SNR). Intrinsic performances (spatial resolution, pixel identification etc.) were optimized first. Arrays of scintillators (NaI(Tl)) of different pixel pitch (down to the present technological limits for NaI(Tl) arrays fabrication (pitch of 2times2 mm2, 1.5times1.5 mm2 and 1.2times1.2 mm2 )) were coupled to arrays of PSPMTs with two anode readout element dimensions (6times6 mm2 and 3times3 mm2). Detectors having field of view of 100times100 mm2 and 150times200 mm2 were designed and built. An electronics system for reading out all the anode pad signals has been designed and constructed. Finally the collimation technique was considered. The limits of the coded aperture option have been studied. Preliminary results of these studies are presented
{"title":"High resolution and high sensitivity detectors for functional molecular imaging with radionuclides: the role of scintillator pixel size, photodetector anode pitch, collimation technique, and of the readout","authors":"F. Garibaldi, R. Accorsi, M. Cinti, E. Cisbani, S. Colilli, F. Cusanno, R. Fratoni, F. Giuliani, M. Gricia, R. Lanza, S. Meo, M. Lucentini, S. Majewski, R. Pani, R. Pellegrini, F. Santavenere, B. M. W. Tsui","doi":"10.1109/NSSMIC.2005.1596919","DOIUrl":"https://doi.org/10.1109/NSSMIC.2005.1596919","url":null,"abstract":"Good spatial resolution and high sensitivity are required for detectors to be used for most of the bio-medical research and application (small animal imaging, detection of small tumors). In this paper we report on parameter optimization of single photon gamma rays detectors. Simulations and measurements were performed for designing and building detectors for early detection of small tumors in breast and in small animal imaging. Critical parameters are: contrast and signal to noise ratio (SNR). Intrinsic performances (spatial resolution, pixel identification etc.) were optimized first. Arrays of scintillators (NaI(Tl)) of different pixel pitch (down to the present technological limits for NaI(Tl) arrays fabrication (pitch of 2times2 mm2, 1.5times1.5 mm2 and 1.2times1.2 mm2 )) were coupled to arrays of PSPMTs with two anode readout element dimensions (6times6 mm2 and 3times3 mm2). Detectors having field of view of 100times100 mm2 and 150times200 mm2 were designed and built. An electronics system for reading out all the anode pad signals has been designed and constructed. Finally the collimation technique was considered. The limits of the coded aperture option have been studied. Preliminary results of these studies are presented","PeriodicalId":105619,"journal":{"name":"IEEE Nuclear Science Symposium Conference Record, 2005","volume":"28 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":"128128272","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.2005.1596789
A. Zamyatin, K. Taguchi, M. Silver
In practice cone beam CT reconstruction is often done using the approximate Feldkamp-type algorithms because of their flexibility and simplicity; however, when it comes to a 64- and higher detector row CT, they produce cone beam artifacts, and for 256+ detector-row CT image quality becomes unacceptable. The exact algorithms, on the other hand, produce artifact-free images but are much more computationally demanding and not very flexible in controlling noise/resolution trade-off. We propose a cone beam algorithm that can be easily adjusted depending on the cone angle. We tested it on 64-slice real data and 320-slice simulated data. For 64-slice CT it outperforms helical Feldkamp in both image quality and volume reconstruction speed; using the same redundancy weighting it reduces the cone beam artifact and improves noise uniformity. Because weighting is done after the convolution step, we can use the n-PI Tam-Danielson window, an exact cone beam weighting. We show that the weighting is more important than the filtering direction for image quality. The proposed method has good image quality without rebinning to tangential filtering lines. In evaluation we compare the proposed algorithm to helical Feldkamp and the 1-PI and 3-PI Katsevich algorithms.
{"title":"Reconstruction algorithm for wide cone beam helical CT","authors":"A. Zamyatin, K. Taguchi, M. Silver","doi":"10.1109/NSSMIC.2005.1596789","DOIUrl":"https://doi.org/10.1109/NSSMIC.2005.1596789","url":null,"abstract":"In practice cone beam CT reconstruction is often done using the approximate Feldkamp-type algorithms because of their flexibility and simplicity; however, when it comes to a 64- and higher detector row CT, they produce cone beam artifacts, and for 256+ detector-row CT image quality becomes unacceptable. The exact algorithms, on the other hand, produce artifact-free images but are much more computationally demanding and not very flexible in controlling noise/resolution trade-off. We propose a cone beam algorithm that can be easily adjusted depending on the cone angle. We tested it on 64-slice real data and 320-slice simulated data. For 64-slice CT it outperforms helical Feldkamp in both image quality and volume reconstruction speed; using the same redundancy weighting it reduces the cone beam artifact and improves noise uniformity. Because weighting is done after the convolution step, we can use the n-PI Tam-Danielson window, an exact cone beam weighting. We show that the weighting is more important than the filtering direction for image quality. The proposed method has good image quality without rebinning to tangential filtering lines. In evaluation we compare the proposed algorithm to helical Feldkamp and the 1-PI and 3-PI Katsevich algorithms.","PeriodicalId":105619,"journal":{"name":"IEEE Nuclear Science Symposium Conference Record, 2005","volume":"18 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":"121690031","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.2005.1596795
Nianming Zuo, D. Xia, E. Sidky, Lifeng Yu, Y. Zou, Xiaochuan Pan, T. Jiang
Helical CT scanners with multi-row detectors have gained wide popularity in clinics. With increasing interest in extending the number of detector rows, the cone angle must be accounted for in image reconstruction algorithms. As the cone angle increases, artifacts in reconstructed images caused by approximate algorithms, such as the widely used FDK-based algorithms, become more of a factor that degrades the image quality. Recently, a novel reconstruction algorithm for helical cone-beam CT (CB-CT) has been proposed, which is referred to as the backprojection-filtration algorithm. This algorithm requires theoretically minimum data to reconstruct a volume image. The original BPF algorithm was presented by assuming a flat-panel detector. However, most current multi-row detectors employed in clinic CT scanners are curved detectors. In this work, we modify the backprojection-filtration (BPF) algorithm to allow for reconstruction from data collected with a curved detector. We perform simulation studies using the Shepp-Logan phantom to evaluate the modified BPF algorithm.
{"title":"Backprojection-filtration reconstruction for helical cone-beam CT with curved detectors","authors":"Nianming Zuo, D. Xia, E. Sidky, Lifeng Yu, Y. Zou, Xiaochuan Pan, T. Jiang","doi":"10.1109/NSSMIC.2005.1596795","DOIUrl":"https://doi.org/10.1109/NSSMIC.2005.1596795","url":null,"abstract":"Helical CT scanners with multi-row detectors have gained wide popularity in clinics. With increasing interest in extending the number of detector rows, the cone angle must be accounted for in image reconstruction algorithms. As the cone angle increases, artifacts in reconstructed images caused by approximate algorithms, such as the widely used FDK-based algorithms, become more of a factor that degrades the image quality. Recently, a novel reconstruction algorithm for helical cone-beam CT (CB-CT) has been proposed, which is referred to as the backprojection-filtration algorithm. This algorithm requires theoretically minimum data to reconstruct a volume image. The original BPF algorithm was presented by assuming a flat-panel detector. However, most current multi-row detectors employed in clinic CT scanners are curved detectors. In this work, we modify the backprojection-filtration (BPF) algorithm to allow for reconstruction from data collected with a curved detector. We perform simulation studies using the Shepp-Logan phantom to evaluate the modified BPF algorithm.","PeriodicalId":105619,"journal":{"name":"IEEE Nuclear Science Symposium Conference Record, 2005","volume":"24 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":"125041816","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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