Pub Date : 2016-10-01DOI: 10.1109/NSSMIC.2016.8069431
Jizhe Wang, Tao Feng, Jingyan Xu, B. Tsui
The goal is to develop and evaluate a new constrained feature-based cardiac motion estimation (ME) method for cardiac gated (CG) myocardial perfusion (MP) PET images to improve the accuracy of the estimated cardiac motion vector field (MVF). CG-MP PET projection data were generated from the 4D XCAT phantom with realistic anatomical structures and cardiac MVF models, and reconstructed using the STIR simulation and reconstruction software. The interventricular sulcus (IS) was extracted from each CG-MP PET image by applying B-spline extrapolation and interpolation methods to the extracted edges of the left (LV) and right ventricular (RV) walls. The estimated MVFs of the extracted ISs were calculated between adjacent CG frames. In the previously feature-based cardiac ME algorithm, the estimated IS MVF was used as an initial estimate in the conventional optical-flow ME algorithm. The information was found to reduce the aperture problem effect and provide more accurate cardiac MVF estimate as compared to without the information, using the cardiac MVF of the XCAT as the truth. In the new algorithm, it was used as an additional constraint to restrict the range of the search for the cardiac MVF estimate. The new approach was evaluated in terms of accuracy of the estimated cardiac MVF and compared with those using the previous methods. The evaluation results showed the estimated cardiac MVF obtained from using the IS as an initial estimate (S-initial) was more accurate than that using no initial estimate (0-initial) and was comparable to that using the truth MVF as the initial estimate (T-initial). The estimation accuracy was further improved with the S-initial and the IS motion as an additional constraint. In conclusion, we developed and evaluated a new constrained feature-based cardiac ME method for cardiac PET. We demonstrated the new method provided more accurate estimation of the cardiac MVF as compared to the conventional and a previously developed feature-based cardiac ME method for CG-MP PET.
{"title":"A constrained feature-based cardiac motion estimation method for cardiac PET","authors":"Jizhe Wang, Tao Feng, Jingyan Xu, B. Tsui","doi":"10.1109/NSSMIC.2016.8069431","DOIUrl":"https://doi.org/10.1109/NSSMIC.2016.8069431","url":null,"abstract":"The goal is to develop and evaluate a new constrained feature-based cardiac motion estimation (ME) method for cardiac gated (CG) myocardial perfusion (MP) PET images to improve the accuracy of the estimated cardiac motion vector field (MVF). CG-MP PET projection data were generated from the 4D XCAT phantom with realistic anatomical structures and cardiac MVF models, and reconstructed using the STIR simulation and reconstruction software. The interventricular sulcus (IS) was extracted from each CG-MP PET image by applying B-spline extrapolation and interpolation methods to the extracted edges of the left (LV) and right ventricular (RV) walls. The estimated MVFs of the extracted ISs were calculated between adjacent CG frames. In the previously feature-based cardiac ME algorithm, the estimated IS MVF was used as an initial estimate in the conventional optical-flow ME algorithm. The information was found to reduce the aperture problem effect and provide more accurate cardiac MVF estimate as compared to without the information, using the cardiac MVF of the XCAT as the truth. In the new algorithm, it was used as an additional constraint to restrict the range of the search for the cardiac MVF estimate. The new approach was evaluated in terms of accuracy of the estimated cardiac MVF and compared with those using the previous methods. The evaluation results showed the estimated cardiac MVF obtained from using the IS as an initial estimate (S-initial) was more accurate than that using no initial estimate (0-initial) and was comparable to that using the truth MVF as the initial estimate (T-initial). The estimation accuracy was further improved with the S-initial and the IS motion as an additional constraint. In conclusion, we developed and evaluated a new constrained feature-based cardiac ME method for cardiac PET. We demonstrated the new method provided more accurate estimation of the cardiac MVF as compared to the conventional and a previously developed feature-based cardiac ME method for CG-MP PET.","PeriodicalId":184587,"journal":{"name":"2016 IEEE Nuclear Science Symposium, Medical Imaging Conference and Room-Temperature Semiconductor Detector Workshop (NSS/MIC/RTSD)","volume":"83 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114495258","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 : 2016-10-01DOI: 10.1109/NSSMIC.2016.8069413
R. Chil, G. Konstantinou, M. Desco, J. Vaquero
We introduce a compact preclinical PET detector that combines the output from 64 SiPM channels, forming an 8×8 matrix of pixels capable of efficiently encoding event position, with good energy and time resolution, as well as depth of interaction information. The scintillator matrices used to characterize the detector are a 16×16 matrix comprised of 1.3×1.3×12mm3 LYSO crystals, and a 1.3×1.3×15mm3 GSO/LYSO phoswhich. Preliminary results regarding spatial resolution show that the detector has a resolvability index of 0.25, an energy resolution below 14% for the 511KeV peak and a good separation between the two different phoswich crystal layers. Due to the compactness and MR compatibility of this detector it is proposed as a candidate to substitute those based on the R8900 PS-PMT in a full ring system that could be inserted into the MR bore of a preclinical PET-MR imager.
{"title":"Compact, MR compatible SiPM small animal PET DOI detector","authors":"R. Chil, G. Konstantinou, M. Desco, J. Vaquero","doi":"10.1109/NSSMIC.2016.8069413","DOIUrl":"https://doi.org/10.1109/NSSMIC.2016.8069413","url":null,"abstract":"We introduce a compact preclinical PET detector that combines the output from 64 SiPM channels, forming an 8×8 matrix of pixels capable of efficiently encoding event position, with good energy and time resolution, as well as depth of interaction information. The scintillator matrices used to characterize the detector are a 16×16 matrix comprised of 1.3×1.3×12mm3 LYSO crystals, and a 1.3×1.3×15mm3 GSO/LYSO phoswhich. Preliminary results regarding spatial resolution show that the detector has a resolvability index of 0.25, an energy resolution below 14% for the 511KeV peak and a good separation between the two different phoswich crystal layers. Due to the compactness and MR compatibility of this detector it is proposed as a candidate to substitute those based on the R8900 PS-PMT in a full ring system that could be inserted into the MR bore of a preclinical PET-MR imager.","PeriodicalId":184587,"journal":{"name":"2016 IEEE Nuclear Science Symposium, Medical Imaging Conference and Room-Temperature Semiconductor Detector Workshop (NSS/MIC/RTSD)","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116748340","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 : 2016-10-01DOI: 10.1109/NSSMIC.2016.8069659
J. Qin, Lei Zhao, Yiming Lu, B. Cheng, Shubin Liu, Q. An
Waveform of the pulse from detectors carry the maximum possible information, and the high demands of fast waveform digitizing led to the development of switched capacitor arrays (SCAs). A prototype of two channels transient waveform digitization ASIC has been designed and fabricated in global foundry 0.18 urn CMOS process. Each channel employs a SCA structure of 128 samples deep, and the high speed sample clock is provided by an on-chip delay-locked loop (DLL). After waveform capture, the analog signal is fed into 128 parallel 12-bit ramp-comparator analog to digital convertors (ADCs), then followed by a serialized readout module with 200 MHz rate. Based on the simulate results, input analog bandwidth is more than 300 MHz and sampling speed can be adjusted from 0.5 to 2 GSa/s, and after amplitude and time calibration, a full 1 V signal voltage range is available, and the Signal-to-Noise Ratio (SNR) reaches 56 dB at 200 MHz input. Data of each channel can be read out in under 10 μs, respectively.
{"title":"A GHz waveform recorder and digitizer ASIC","authors":"J. Qin, Lei Zhao, Yiming Lu, B. Cheng, Shubin Liu, Q. An","doi":"10.1109/NSSMIC.2016.8069659","DOIUrl":"https://doi.org/10.1109/NSSMIC.2016.8069659","url":null,"abstract":"Waveform of the pulse from detectors carry the maximum possible information, and the high demands of fast waveform digitizing led to the development of switched capacitor arrays (SCAs). A prototype of two channels transient waveform digitization ASIC has been designed and fabricated in global foundry 0.18 urn CMOS process. Each channel employs a SCA structure of 128 samples deep, and the high speed sample clock is provided by an on-chip delay-locked loop (DLL). After waveform capture, the analog signal is fed into 128 parallel 12-bit ramp-comparator analog to digital convertors (ADCs), then followed by a serialized readout module with 200 MHz rate. Based on the simulate results, input analog bandwidth is more than 300 MHz and sampling speed can be adjusted from 0.5 to 2 GSa/s, and after amplitude and time calibration, a full 1 V signal voltage range is available, and the Signal-to-Noise Ratio (SNR) reaches 56 dB at 200 MHz input. Data of each channel can be read out in under 10 μs, respectively.","PeriodicalId":184587,"journal":{"name":"2016 IEEE Nuclear Science Symposium, Medical Imaging Conference and Room-Temperature Semiconductor Detector Workshop (NSS/MIC/RTSD)","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128339873","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 : 2016-10-01DOI: 10.1109/NSSMIC.2016.8069540
M. Miklavec, D. Savran, S. Širca, M. Vencelj
Delivering precisely the desired dose distribution to the patient during radiotherapy is of crucial importance for treatment success and monitoring the actual distributed dose opens the possibility to correct for deposition inaccuracies and thus achieve better conformance to the treatment plan. Positron emission tomography has already been successfully used to measure the residual radioactivity from (γ, n) reactions in the patient after the treatment with hadron therapy or high-energy gamma-ray radiotherapy (above ∼20 MV) [1], [2]. When trying to use a similar approach for gamma-rays of lower energies (most commonly 6 to 18 MV) the only source of positrons is prompt pair production in the beam, calling for measurements while the linac is operating and saturating the detector. The problems with saturation were alleviated to a formidable extent by using advanced digital processing techniques to measure energies of incident particles at rates beyond 10 Mcps per each scintillation crystal. The approach suggested by [3] builds on the discovery that there is a strong correlation between the delivered dose and the density of pair production. Our research confirmed the findings, but only as long as homogeneous objects were involved. In an inhomogeneous object, the annihilation density was no longer proportional to the dose, but rather to the density of deposited energy. This means that the intimate knowledge of the material density is required for proper reconstruction of the dose field image from the PET measurement. Additionally, one gets 2–4 mm thick regions at material boundaries where the charge particle equilibrium gets broken and the correlation no longer holds. This is, in principle, possible to account for based on ct data that is always available in such cases, but definitely calls for further work.
{"title":"Influence of tissue non-homogeneities on the accuracy of 3-D dose distribution monitoring during gamma-ray radiotherapy","authors":"M. Miklavec, D. Savran, S. Širca, M. Vencelj","doi":"10.1109/NSSMIC.2016.8069540","DOIUrl":"https://doi.org/10.1109/NSSMIC.2016.8069540","url":null,"abstract":"Delivering precisely the desired dose distribution to the patient during radiotherapy is of crucial importance for treatment success and monitoring the actual distributed dose opens the possibility to correct for deposition inaccuracies and thus achieve better conformance to the treatment plan. Positron emission tomography has already been successfully used to measure the residual radioactivity from (γ, n) reactions in the patient after the treatment with hadron therapy or high-energy gamma-ray radiotherapy (above ∼20 MV) [1], [2]. When trying to use a similar approach for gamma-rays of lower energies (most commonly 6 to 18 MV) the only source of positrons is prompt pair production in the beam, calling for measurements while the linac is operating and saturating the detector. The problems with saturation were alleviated to a formidable extent by using advanced digital processing techniques to measure energies of incident particles at rates beyond 10 Mcps per each scintillation crystal. The approach suggested by [3] builds on the discovery that there is a strong correlation between the delivered dose and the density of pair production. Our research confirmed the findings, but only as long as homogeneous objects were involved. In an inhomogeneous object, the annihilation density was no longer proportional to the dose, but rather to the density of deposited energy. This means that the intimate knowledge of the material density is required for proper reconstruction of the dose field image from the PET measurement. Additionally, one gets 2–4 mm thick regions at material boundaries where the charge particle equilibrium gets broken and the correlation no longer holds. This is, in principle, possible to account for based on ct data that is always available in such cases, but definitely calls for further work.","PeriodicalId":184587,"journal":{"name":"2016 IEEE Nuclear Science Symposium, Medical Imaging Conference and Room-Temperature Semiconductor Detector Workshop (NSS/MIC/RTSD)","volume":"55 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128593629","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 : 2016-10-01DOI: 10.1109/NSSMIC.2016.8069913
E. De Lucia, A. Balla, G. Bencivenni, P. Branchini, A. Budano, M. Capodiferro, S. Cerioni, P. Ciambrone, E. Czerwiński, G. de Robertis, A. Di Cicco, D. Domenici, J. Dong, G. Felici, P. Fermani, M. Gatta, N. Lacalamita, F. Loddo, M. Mongelli, G. Morello, A. Palladino, A. Pelosi, A. Ranieri, E. Tskhadadze, V. Valentino
KLOE-2 at the e+e− DAφNE φ-factory is the main experiment of the INFN Frascati National Laboratories (LNF) and is the first high-energy experiment using the GEM technology with a cylindrical geometry, a novel idea that was developed at LNF exploiting the kapton properties to build a light and compact tracking system. Four concentric cylindrical triple-GEM detectors, for a total material budget below 2% of the radiation length X0, are inserted around the interaction region and before the inner wall of the pre-existing KLOE Drift Chamber, at distances from 130 mm to 205 mm. For this project, state-of-the-art solutions have been expressly developed or tuned: single-mask GEM etching, multi-layer XV patterned readout circuit, PEEK spacer grid, GASTONE front-end board, a custom 64-channel ASIC with digital output, and the Global Interface Board for data collection, with a configurable FPGA architecture and Gigabit Ethernet. The dedicated XV strips patterned readout allows space coordinates to be reconstructed. Alignment and calibration of a cylindrical GEM detector was never done before and represents one of the challenging activities of the experiment. During 2015 both KLOE-2 and DAPHNE successfully demonstrated the feasibility of a long term acquisition program with the first data taking campaign, started in November 2014 and ended in July 2015 with 1 fb−1 integrated luminosity. The second new data taking campaign started in September 2015 and KLOE-2 is presently taking data. The Inner Tracker detector operation, calibration and performance will be presented. Preliminary results obtained with cosmic-ray muons and Bhabha scattering events are within expectations for the Inner Tracker resolution.
{"title":"The KLOE-2 cylindrical GEM inner tracker: Detector operation, calibration and performance","authors":"E. De Lucia, A. Balla, G. Bencivenni, P. Branchini, A. Budano, M. Capodiferro, S. Cerioni, P. Ciambrone, E. Czerwiński, G. de Robertis, A. Di Cicco, D. Domenici, J. Dong, G. Felici, P. Fermani, M. Gatta, N. Lacalamita, F. Loddo, M. Mongelli, G. Morello, A. Palladino, A. Pelosi, A. Ranieri, E. Tskhadadze, V. Valentino","doi":"10.1109/NSSMIC.2016.8069913","DOIUrl":"https://doi.org/10.1109/NSSMIC.2016.8069913","url":null,"abstract":"KLOE-2 at the e+e− DAφNE φ-factory is the main experiment of the INFN Frascati National Laboratories (LNF) and is the first high-energy experiment using the GEM technology with a cylindrical geometry, a novel idea that was developed at LNF exploiting the kapton properties to build a light and compact tracking system. Four concentric cylindrical triple-GEM detectors, for a total material budget below 2% of the radiation length X0, are inserted around the interaction region and before the inner wall of the pre-existing KLOE Drift Chamber, at distances from 130 mm to 205 mm. For this project, state-of-the-art solutions have been expressly developed or tuned: single-mask GEM etching, multi-layer XV patterned readout circuit, PEEK spacer grid, GASTONE front-end board, a custom 64-channel ASIC with digital output, and the Global Interface Board for data collection, with a configurable FPGA architecture and Gigabit Ethernet. The dedicated XV strips patterned readout allows space coordinates to be reconstructed. Alignment and calibration of a cylindrical GEM detector was never done before and represents one of the challenging activities of the experiment. During 2015 both KLOE-2 and DAPHNE successfully demonstrated the feasibility of a long term acquisition program with the first data taking campaign, started in November 2014 and ended in July 2015 with 1 fb−1 integrated luminosity. The second new data taking campaign started in September 2015 and KLOE-2 is presently taking data. The Inner Tracker detector operation, calibration and performance will be presented. Preliminary results obtained with cosmic-ray muons and Bhabha scattering events are within expectations for the Inner Tracker resolution.","PeriodicalId":184587,"journal":{"name":"2016 IEEE Nuclear Science Symposium, Medical Imaging Conference and Room-Temperature Semiconductor Detector Workshop (NSS/MIC/RTSD)","volume":"94 12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128710508","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 : 2016-10-01DOI: 10.1109/NSSMIC.2016.8069616
M. Vopálenský, I. Kumpová, D. Vavřík
From the point of view of the image quality, the contrast-to-noise ratio (CNR) is a crucial parameter. In case of the scintillation detectors, which are widely used in X-ray radiography and computed tomography, CNR is determined by the static image noise caused mainly by the non-uniformity of the response of particular pixels, and by the stochastic noise, composed of the inherent noise of the detector and the X-ray beam fluctuation. The static noise can be suppressed using appropriate correction methods, such as the flat field correction. The stochastic component of noise can be lowered by averaging of more images of the same scene, but this approach leads to an increased time of the tomography, which can be an undesirable effect. This paper shows a method that separates the stochastic noise component from the static noise component and thus allows to determine the maximum reachable CNR in the given case and the minimum number of images to be averaged for reaching required CNR. The method is intended to be used for optimized setting of the detector and X-ray source parameters in tomography to obtain the best possible results in a reasonable time.
{"title":"Improving the contrast-to-noise ratio by averaging in scintillation detectors","authors":"M. Vopálenský, I. Kumpová, D. Vavřík","doi":"10.1109/NSSMIC.2016.8069616","DOIUrl":"https://doi.org/10.1109/NSSMIC.2016.8069616","url":null,"abstract":"From the point of view of the image quality, the contrast-to-noise ratio (CNR) is a crucial parameter. In case of the scintillation detectors, which are widely used in X-ray radiography and computed tomography, CNR is determined by the static image noise caused mainly by the non-uniformity of the response of particular pixels, and by the stochastic noise, composed of the inherent noise of the detector and the X-ray beam fluctuation. The static noise can be suppressed using appropriate correction methods, such as the flat field correction. The stochastic component of noise can be lowered by averaging of more images of the same scene, but this approach leads to an increased time of the tomography, which can be an undesirable effect. This paper shows a method that separates the stochastic noise component from the static noise component and thus allows to determine the maximum reachable CNR in the given case and the minimum number of images to be averaged for reaching required CNR. The method is intended to be used for optimized setting of the detector and X-ray source parameters in tomography to obtain the best possible results in a reasonable time.","PeriodicalId":184587,"journal":{"name":"2016 IEEE Nuclear Science Symposium, Medical Imaging Conference and Room-Temperature Semiconductor Detector Workshop (NSS/MIC/RTSD)","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129011881","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 : 2016-10-01DOI: 10.1109/NSSMIC.2016.8069643
S. Nowicki, L. Stonehill, D. Coupland, K. Mesick
Planetary gamma-ray and neutron spectroscopy from orbiting spacecraft has become a standard technique to measure distinctive composition and abundance signatures for key elements relevant to planetary structure and evolution. Previous instrumentation that has led to the discovery of the concentration of many elements including hydrogen (a strong indicator of water) on planetary bodies, have used separate gamma-ray and neutron spectrometers. Elpasolite scintillators offer an opportunity to combine the gamma-ray and neutron spectrometer into a single instrument, leading to a significant reduction in instrument size, weight, and power (SWaP). We have developed an Elpasolite Planetary Ice and Composition Spectrometer (EPICS) instrument concept, which utilizes elpasolite scintillator and silicon photomultipliers to offer significantly reduced SWaP with similar neutron and gamma-ray detection efficiency but superior gamma-ray energy resolution compared to current scintillator-based instruments. We will provide an overview and motivation for the EPICS instrument, present preliminary conceptual design simulations that compare our instrument concept to current planetary science instruments, and discuss specific target missions that would benefit from the EPICS instrument.
{"title":"Development of an elpasolite planetary science instrument","authors":"S. Nowicki, L. Stonehill, D. Coupland, K. Mesick","doi":"10.1109/NSSMIC.2016.8069643","DOIUrl":"https://doi.org/10.1109/NSSMIC.2016.8069643","url":null,"abstract":"Planetary gamma-ray and neutron spectroscopy from orbiting spacecraft has become a standard technique to measure distinctive composition and abundance signatures for key elements relevant to planetary structure and evolution. Previous instrumentation that has led to the discovery of the concentration of many elements including hydrogen (a strong indicator of water) on planetary bodies, have used separate gamma-ray and neutron spectrometers. Elpasolite scintillators offer an opportunity to combine the gamma-ray and neutron spectrometer into a single instrument, leading to a significant reduction in instrument size, weight, and power (SWaP). We have developed an Elpasolite Planetary Ice and Composition Spectrometer (EPICS) instrument concept, which utilizes elpasolite scintillator and silicon photomultipliers to offer significantly reduced SWaP with similar neutron and gamma-ray detection efficiency but superior gamma-ray energy resolution compared to current scintillator-based instruments. We will provide an overview and motivation for the EPICS instrument, present preliminary conceptual design simulations that compare our instrument concept to current planetary science instruments, and discuss specific target missions that would benefit from the EPICS instrument.","PeriodicalId":184587,"journal":{"name":"2016 IEEE Nuclear Science Symposium, Medical Imaging Conference and Room-Temperature Semiconductor Detector Workshop (NSS/MIC/RTSD)","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129244060","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 : 2016-10-01DOI: 10.1109/NSSMIC.2016.8069549
M. Schlüter, N. Gdaniec, A. Schlaefer, T. Knopp
The temporal resolution of magnetic particle imaging (MPI) is sufficiently high to capture dynamic processes like cardiac motion. The achievable spatial resolution of MPI is closely linked to the signal-to-noise ratio of the measured voltage signal. Therefore, in practice it can be advantageous to improve the signal-to-noise ratio by block-wise averaging the signal over time. However, this will decrease the temporal resolution such that cardiac motion is not resolved anymore. In the present work, we introduce a framework for averaging MPI data that exhibit periodic motion induced by e.g. respiration and/or the heart beat. The frequency of motion is directly derived from the MPI raw data without the need for an additional navigator signal. The short time Fourier transform is used for this purpose, because each of these periodic movements will have a frequency varying over time. In order to average the captured frames corresponding to the same phase of the motion, one has to calculate virtual frames since the data acquisition and the periodic motion are not synchronized. In a phantom study it is shown that the developed method is capable of averaging experimental data without introducing any motion artifacts.
{"title":"Compensation of periodic motion for averaging of magnetic particle imaging data","authors":"M. Schlüter, N. Gdaniec, A. Schlaefer, T. Knopp","doi":"10.1109/NSSMIC.2016.8069549","DOIUrl":"https://doi.org/10.1109/NSSMIC.2016.8069549","url":null,"abstract":"The temporal resolution of magnetic particle imaging (MPI) is sufficiently high to capture dynamic processes like cardiac motion. The achievable spatial resolution of MPI is closely linked to the signal-to-noise ratio of the measured voltage signal. Therefore, in practice it can be advantageous to improve the signal-to-noise ratio by block-wise averaging the signal over time. However, this will decrease the temporal resolution such that cardiac motion is not resolved anymore. In the present work, we introduce a framework for averaging MPI data that exhibit periodic motion induced by e.g. respiration and/or the heart beat. The frequency of motion is directly derived from the MPI raw data without the need for an additional navigator signal. The short time Fourier transform is used for this purpose, because each of these periodic movements will have a frequency varying over time. In order to average the captured frames corresponding to the same phase of the motion, one has to calculate virtual frames since the data acquisition and the periodic motion are not synchronized. In a phantom study it is shown that the developed method is capable of averaging experimental data without introducing any motion artifacts.","PeriodicalId":184587,"journal":{"name":"2016 IEEE Nuclear Science Symposium, Medical Imaging Conference and Room-Temperature Semiconductor Detector Workshop (NSS/MIC/RTSD)","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124703172","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 : 2016-10-01DOI: 10.1109/NSSMIC.2016.8069707
Hyun Suk Kim, Gyemin Lee, S. Ye, Geehyun Kim
We are currently developing a dual-particle imager based on the rotational modulation collimator (RMC) technique employing Cs2LiYCl6:Ce (CLYC) detector. A symmetric mask design has been conventionally used for RMC, however, it has an intrinsic problem of not being able to distinguish two symmetric sources located with respect to the rotation axis. In the present study, we propose a new design of collimator masks to solve the artifact problem in the source location estimation imposed by the symmetric pattern of collimator masks. We used the Monte Carlo N-Particle 6.1 (MCNP6) code to obtain modulation patterns, and we applied the maximum likelihood expectation maximization (MLEM) algorithm to reconstruct radiation images from the modulation patterns. The asymmetric mask design we proposed in this paper showed enhanced performance in image reconstruction by removing intrinsic artifacts from the symmetric mask design and will be used as a fundamental design for the future development of the dual-particle RMC system.
{"title":"Design of a rotational modulation collimator utilizing asymmetric masks for the gamma-ray/neutron dual imaging technique","authors":"Hyun Suk Kim, Gyemin Lee, S. Ye, Geehyun Kim","doi":"10.1109/NSSMIC.2016.8069707","DOIUrl":"https://doi.org/10.1109/NSSMIC.2016.8069707","url":null,"abstract":"We are currently developing a dual-particle imager based on the rotational modulation collimator (RMC) technique employing Cs2LiYCl6:Ce (CLYC) detector. A symmetric mask design has been conventionally used for RMC, however, it has an intrinsic problem of not being able to distinguish two symmetric sources located with respect to the rotation axis. In the present study, we propose a new design of collimator masks to solve the artifact problem in the source location estimation imposed by the symmetric pattern of collimator masks. We used the Monte Carlo N-Particle 6.1 (MCNP6) code to obtain modulation patterns, and we applied the maximum likelihood expectation maximization (MLEM) algorithm to reconstruct radiation images from the modulation patterns. The asymmetric mask design we proposed in this paper showed enhanced performance in image reconstruction by removing intrinsic artifacts from the symmetric mask design and will be used as a fundamental design for the future development of the dual-particle RMC system.","PeriodicalId":184587,"journal":{"name":"2016 IEEE Nuclear Science Symposium, Medical Imaging Conference and Room-Temperature Semiconductor Detector Workshop (NSS/MIC/RTSD)","volume":"549 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129638902","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 : 2016-10-01DOI: 10.1109/NSSMIC.2016.8069385
Kyungsang Kim, G. Fakhri, Quanzheng Li
Direct parametric estimation in positron emission tomography (PET) has been developed to compute the voxel-based kinetic parameters in the reconstruction process, obtaining more accurate physiological information of tracer uptake. Although the direct parametric imaging can achieve accurate kinetic analysis, the long acquisition time is still painful, particularly for sick and old patients. To address this issue, we explore the feasibility to estimate voxel-based kinetic parameters using partial dynamic data, specifically the first and last 10 minutes of a typical dynamic scan. To improve the quality of the direct parametric imaging with partial dynamic data, we propose a novel penalized direct estimation method containing log-likelihood, ridge regression and patch-based joint similarity penalty of kinetic images, in which the structural similarity weight of K1 can be used for improving the features in other kinetic images (k2 ∼ k4). In our optimization, the alternating direction method of multipliers (ADMM) with a separable quadratic surrogate (SQS) is exploited. We validate the proposed method using a brain phantom, and demonstrate that the proposed method outperforms the conventional direct estimation methods even using partial dynamic data.
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