Pub Date : 2016-10-01DOI: 10.1109/NSSMIC.2016.8069457
P. Gravel, J. Soucy, A. Reader
This work evaluates a maximum likelihood parameter estimation method for regions-of-interest (ML-ROI) when incorporated in a direct 4D PET image reconstruction framework including the simplified reference tissue model with the basis function method (SRTM-BFM) tracer kinetic model. The ML-ROI algorithm has been evaluated for the usual task of estimating the radioactivity concentration for ROI spatial-bases compared to voxels. We therefore extend the application of this method to include the direct estimation of binding potential (BP) values on simulated 2D+time data sets (with use of [11C]raclopride time-activity curves (TACs) from real data). The performance of the proposed method is evaluated by comparing BP estimates with those obtained from a conventional post reconstruction approach, as well as the original ML-ROI method. It is shown that the use of ROIs as spatial basis functions leads to much lower %RMSE for BP regional estimates (%RMSE reduced by a factor of 2 or more), and furthermore using direct BP estimation in conjunction with ROI spatial basis functions reduces the still further. However, the major improvement is from the use of ROI spatial basis functions, rather than the use of direct kinetic parameter estimation. On the other hand, the considerable time gained (2 orders of magnitude) makes it a potential candidate for routine application.
{"title":"Direct PET reconstruction of regional binding potentials","authors":"P. Gravel, J. Soucy, A. Reader","doi":"10.1109/NSSMIC.2016.8069457","DOIUrl":"https://doi.org/10.1109/NSSMIC.2016.8069457","url":null,"abstract":"This work evaluates a maximum likelihood parameter estimation method for regions-of-interest (ML-ROI) when incorporated in a direct 4D PET image reconstruction framework including the simplified reference tissue model with the basis function method (SRTM-BFM) tracer kinetic model. The ML-ROI algorithm has been evaluated for the usual task of estimating the radioactivity concentration for ROI spatial-bases compared to voxels. We therefore extend the application of this method to include the direct estimation of binding potential (BP) values on simulated 2D+time data sets (with use of [11C]raclopride time-activity curves (TACs) from real data). The performance of the proposed method is evaluated by comparing BP estimates with those obtained from a conventional post reconstruction approach, as well as the original ML-ROI method. It is shown that the use of ROIs as spatial basis functions leads to much lower %RMSE for BP regional estimates (%RMSE reduced by a factor of 2 or more), and furthermore using direct BP estimation in conjunction with ROI spatial basis functions reduces the still further. However, the major improvement is from the use of ROI spatial basis functions, rather than the use of direct kinetic parameter estimation. On the other hand, the considerable time gained (2 orders of magnitude) makes it a potential candidate for routine application.","PeriodicalId":184587,"journal":{"name":"2016 IEEE Nuclear Science Symposium, Medical Imaging Conference and Room-Temperature Semiconductor Detector Workshop (NSS/MIC/RTSD)","volume":"43 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":"125593519","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.2016.8069714
C. Lee, D. Chang, B. Oh, J. Son, Yong-Kyun Kim
Penning ion source was made for applying a compact neutron generator. Electrical and vacuum system was assembled to test the ion source. As a preliminary test, a hydrogen gas using a mass flow system was inserted to produce plasma into the ion source and the plasma was produced and the hydrogen ion beams were extracted successfully. Operation conditions such as anode voltage, pressure change, and extraction voltage were changed to extract a higher current of the hydrogen ion beams and the highest current was achieved to be 0.9 mA at 0.0021 mbar (40 sccm) and 7.5 kV anode biased voltage. Some details on the operation conditions of the penning ion source were discussed.
{"title":"Hydrogen beam extraction of penning ion source for compact neutron generator","authors":"C. Lee, D. Chang, B. Oh, J. Son, Yong-Kyun Kim","doi":"10.1109/NSSMIC.2016.8069714","DOIUrl":"https://doi.org/10.1109/NSSMIC.2016.8069714","url":null,"abstract":"Penning ion source was made for applying a compact neutron generator. Electrical and vacuum system was assembled to test the ion source. As a preliminary test, a hydrogen gas using a mass flow system was inserted to produce plasma into the ion source and the plasma was produced and the hydrogen ion beams were extracted successfully. Operation conditions such as anode voltage, pressure change, and extraction voltage were changed to extract a higher current of the hydrogen ion beams and the highest current was achieved to be 0.9 mA at 0.0021 mbar (40 sccm) and 7.5 kV anode biased voltage. Some details on the operation conditions of the penning ion source were discussed.","PeriodicalId":184587,"journal":{"name":"2016 IEEE Nuclear Science Symposium, Medical Imaging Conference and Room-Temperature Semiconductor Detector Workshop (NSS/MIC/RTSD)","volume":"25 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":"126736666","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.2016.8069834
Toru Matsumura, T. Shinkawa
Li-containing scintillators arranged in cage-shaped are proposed as a fast-neutron imager for nuclear security. Counting rate difference among the scintillators enables us to reconstruct the direction of neutron source by the aid of an iterative-Bayesian unfolding method. Simulation studies show that the proposed imager has angular resolution of 10 degrees and even identifies multiple source directions. The simulation can reproduce experimental results with a prototype detector. This indicates that the idea of the fast neutron imager is feasible.
{"title":"A portable fast-neutron imager with 6Li-containing scintillators","authors":"Toru Matsumura, T. Shinkawa","doi":"10.1109/NSSMIC.2016.8069834","DOIUrl":"https://doi.org/10.1109/NSSMIC.2016.8069834","url":null,"abstract":"Li-containing scintillators arranged in cage-shaped are proposed as a fast-neutron imager for nuclear security. Counting rate difference among the scintillators enables us to reconstruct the direction of neutron source by the aid of an iterative-Bayesian unfolding method. Simulation studies show that the proposed imager has angular resolution of 10 degrees and even identifies multiple source directions. The simulation can reproduce experimental results with a prototype detector. This indicates that the idea of the fast neutron imager is feasible.","PeriodicalId":184587,"journal":{"name":"2016 IEEE Nuclear Science Symposium, Medical Imaging Conference and Room-Temperature Semiconductor Detector Workshop (NSS/MIC/RTSD)","volume":"69 2 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":"122231672","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.2016.8069532
A. Könik, J. M. Mukherjee, Soumyanil Banerjee, J. De Beenhouwer, G. Zubal, M. King
We proposed an inexpensive method to improve the performance of the conventional dual-camera SPECT systems for I-123 dopamine transporter (DAT) imaging for Parkinson Disease. In this method, one of the collimators is replaced with a specifically designed multi-pinhole (MPH) collimator, thus performing combined MPH/Fanbeam acquisition. The MPH consists of 9 pinholes focusing to the central brain and covering a cylindrical field of view (diameter: 12cm and height: 8cm), which includes the striatum. We present here our Monte Carlo simulation work investigating the optimal aperture size for the striatal binding ratio (SBR) and caudate/putamen ratio (C/P). Projections of the XCAT brain phantom were obtained for a range of aperture sizes (radius:1–5 mm, with increments of 1mm). Multiple noise realizations were simulated for each aperture size at realistic count levels. Reconstructions from MPH, Fanbeam and combined MPH/Fanbeam systems were obtained for various numbers of iterations. For SBR and C/P calculations activities within the striatum were estimated for a range of region of interests. Normalized root mean square errors (NRMSE) of the SBR and C/P measurements were obtained for the Fanbeam and combined MPH/Fanbeam reconstructions at different iterations and VOIs, using custom made and clinically employed quantitative analysis software. Our preliminary results suggest that an aperture radius of 2-3 mm for the MPH component yields both visually and quantitatively better estimations for the MPH/Fanbeam reconstructions.
{"title":"Optimization of pinhole aperture size of a combined MPH/fanbeam SPECT system for I-123 DAT imaging","authors":"A. Könik, J. M. Mukherjee, Soumyanil Banerjee, J. De Beenhouwer, G. Zubal, M. King","doi":"10.1109/NSSMIC.2016.8069532","DOIUrl":"https://doi.org/10.1109/NSSMIC.2016.8069532","url":null,"abstract":"We proposed an inexpensive method to improve the performance of the conventional dual-camera SPECT systems for I-123 dopamine transporter (DAT) imaging for Parkinson Disease. In this method, one of the collimators is replaced with a specifically designed multi-pinhole (MPH) collimator, thus performing combined MPH/Fanbeam acquisition. The MPH consists of 9 pinholes focusing to the central brain and covering a cylindrical field of view (diameter: 12cm and height: 8cm), which includes the striatum. We present here our Monte Carlo simulation work investigating the optimal aperture size for the striatal binding ratio (SBR) and caudate/putamen ratio (C/P). Projections of the XCAT brain phantom were obtained for a range of aperture sizes (radius:1–5 mm, with increments of 1mm). Multiple noise realizations were simulated for each aperture size at realistic count levels. Reconstructions from MPH, Fanbeam and combined MPH/Fanbeam systems were obtained for various numbers of iterations. For SBR and C/P calculations activities within the striatum were estimated for a range of region of interests. Normalized root mean square errors (NRMSE) of the SBR and C/P measurements were obtained for the Fanbeam and combined MPH/Fanbeam reconstructions at different iterations and VOIs, using custom made and clinically employed quantitative analysis software. Our preliminary results suggest that an aperture radius of 2-3 mm for the MPH component yields both visually and quantitatively better estimations for the MPH/Fanbeam reconstructions.","PeriodicalId":184587,"journal":{"name":"2016 IEEE Nuclear Science Symposium, Medical Imaging Conference and Room-Temperature Semiconductor Detector Workshop (NSS/MIC/RTSD)","volume":"4 3","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114113848","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.2016.8069894
B. Siddi
Faster alternatives to a full, GEANT4-based simulation are being pursued within LHCb experiment. In this context the integration of the Delphes toolkit in the LHCb simulation framework is intended to provide a fully parameterized option. Delphes is a modular software designed to perform fast simulations by propagating stable particles using a parametric approach and providing reconstructed physical objects as output. It includes propagation inside a magnetic field and parameterized response for tracking and muon systems as well as calorimetric response. Particle energies are computed by smearing the initial visible particles momenta according to detector resolution in a highly-customizable way. Delphes was initially designed for general-purpose experiments such as ATLAS and CMS where is already used. The present contribution illustrates the different aspect of the integration of the Delphes toolkit in Gauss, the LHCb simulation framework. Technically the particle transport performed by GEANT4 and subsequent mimicking of detector response and reconstruction has been replaced with a parametric response of the various detector elements. The implementation required extension to Delphes itself to constrain the particle transport inside the spectrometer acceptance, in order to match the LHCb dipole magnetic field. The configuration of various parameterizations of resolution and efficiency (charged particle tracking, mis-identification rate of particle identification algorithms, calorimeter, trigger response) is also a major aspect of the work to provide a fully functional simulation system. The output of the resulting fast simulation is formatted in such a way that can be used in the LHCb physics analysis framework. The status of the integration of Delphes is given.
{"title":"Development and deployment of a fully parameterized fast Monte Carlo simulation in LHCb","authors":"B. Siddi","doi":"10.1109/NSSMIC.2016.8069894","DOIUrl":"https://doi.org/10.1109/NSSMIC.2016.8069894","url":null,"abstract":"Faster alternatives to a full, GEANT4-based simulation are being pursued within LHCb experiment. In this context the integration of the Delphes toolkit in the LHCb simulation framework is intended to provide a fully parameterized option. Delphes is a modular software designed to perform fast simulations by propagating stable particles using a parametric approach and providing reconstructed physical objects as output. It includes propagation inside a magnetic field and parameterized response for tracking and muon systems as well as calorimetric response. Particle energies are computed by smearing the initial visible particles momenta according to detector resolution in a highly-customizable way. Delphes was initially designed for general-purpose experiments such as ATLAS and CMS where is already used. The present contribution illustrates the different aspect of the integration of the Delphes toolkit in Gauss, the LHCb simulation framework. Technically the particle transport performed by GEANT4 and subsequent mimicking of detector response and reconstruction has been replaced with a parametric response of the various detector elements. The implementation required extension to Delphes itself to constrain the particle transport inside the spectrometer acceptance, in order to match the LHCb dipole magnetic field. The configuration of various parameterizations of resolution and efficiency (charged particle tracking, mis-identification rate of particle identification algorithms, calorimeter, trigger response) is also a major aspect of the work to provide a fully functional simulation system. The output of the resulting fast simulation is formatted in such a way that can be used in the LHCb physics analysis framework. The status of the integration of Delphes is given.","PeriodicalId":184587,"journal":{"name":"2016 IEEE Nuclear Science Symposium, Medical Imaging Conference and Room-Temperature Semiconductor Detector Workshop (NSS/MIC/RTSD)","volume":"43 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":"114195244","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.2016.8069790
Nathaniel S. Edwards, B. Montag, L. C. Henson, S. Bellinger, R. Fronk, M. Reichenberger, D. Mcgregor
Microstrip electrodes have been fabricated and combined with one and five suspended 6Li foils positioned within a pressurized, gas-filled chamber to create a suspended foil microstrip neutron detector. This new detector offers a mechanically and electrically robust alternative to multi-wire proportional counters. Incident neutrons are converted into charged-particle reaction products that ionize the backfill gas. Charge carriers produced from the ionization of the backfill gas drift toward their respectively-charged electrodes due to the influence of the electric field formed from the potential difference between the drift electrode and the microstrip electrode anode and cathode strips. Gas multiplication occurs as electrons approach the surface of the microstrip electrode resulting in an increase in signal amplitude. Suspended foil microstrip neutron detectors containing one and five suspended 6Li foils were simulated using MCNP6 and compared to experimental results. The measured count rates from a moderated 26-ng 252Cf source positioned 18 cm from microstrip neutron detectors equipped with one and five suspended 6Li foils were 3.25 ± 0.04 and 10.62 ± 0.14 counts per second, respectively. The intrinsic thermal neutron detection efficiency of each detector was 4.02 ± 0.04% and 14.58 ± 0.11% for one and five suspended 6Li foils, respectively.
{"title":"Lithium foil gas-filled neutron detector using microstrip electrodes","authors":"Nathaniel S. Edwards, B. Montag, L. C. Henson, S. Bellinger, R. Fronk, M. Reichenberger, D. Mcgregor","doi":"10.1109/NSSMIC.2016.8069790","DOIUrl":"https://doi.org/10.1109/NSSMIC.2016.8069790","url":null,"abstract":"Microstrip electrodes have been fabricated and combined with one and five suspended 6Li foils positioned within a pressurized, gas-filled chamber to create a suspended foil microstrip neutron detector. This new detector offers a mechanically and electrically robust alternative to multi-wire proportional counters. Incident neutrons are converted into charged-particle reaction products that ionize the backfill gas. Charge carriers produced from the ionization of the backfill gas drift toward their respectively-charged electrodes due to the influence of the electric field formed from the potential difference between the drift electrode and the microstrip electrode anode and cathode strips. Gas multiplication occurs as electrons approach the surface of the microstrip electrode resulting in an increase in signal amplitude. Suspended foil microstrip neutron detectors containing one and five suspended 6Li foils were simulated using MCNP6 and compared to experimental results. The measured count rates from a moderated 26-ng 252Cf source positioned 18 cm from microstrip neutron detectors equipped with one and five suspended 6Li foils were 3.25 ± 0.04 and 10.62 ± 0.14 counts per second, respectively. The intrinsic thermal neutron detection efficiency of each detector was 4.02 ± 0.04% and 14.58 ± 0.11% for one and five suspended 6Li foils, respectively.","PeriodicalId":184587,"journal":{"name":"2016 IEEE Nuclear Science Symposium, Medical Imaging Conference and Room-Temperature Semiconductor Detector Workshop (NSS/MIC/RTSD)","volume":"40 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":"120922990","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.2016.8069476
Dong Sik Kim, Eunae Lee
In order to measure the noise power spectrum (NPS) of a radiography detector from acquired images without any object, a subtraction-based algorithm, in which the input image is subtracted from another image acquired at the same exposure condition, is usually used to alleviate the fixed pattern noise influence. However, depending on variations in the x-ray tube and the readout circuits in the detector, the acquired images show nonuniform statistics and thus selecting an appropriate image pair from a given image set is important for a stable measurement of NPS. In order to select a good image pair for measuring an accurate normalized NPS (NNPS), a measurement method is proposed based on selecting an image pair from comparing the signal-to-noise ratios, which are obtained from the subtracted image. For the comparison, a commutative relationship as a sufficient condition for the accurate NNPS is considered. For a given image pair, the proposed method can provide a degree of accuracy of the empirical NNPS. For real x-ray images acquired from an indirect radiography detector, the proposed method is tested and shows stable measuring results for a set of images.
{"title":"Empirical noise power spectrum based on the image subtraction in radiography imaging","authors":"Dong Sik Kim, Eunae Lee","doi":"10.1109/NSSMIC.2016.8069476","DOIUrl":"https://doi.org/10.1109/NSSMIC.2016.8069476","url":null,"abstract":"In order to measure the noise power spectrum (NPS) of a radiography detector from acquired images without any object, a subtraction-based algorithm, in which the input image is subtracted from another image acquired at the same exposure condition, is usually used to alleviate the fixed pattern noise influence. However, depending on variations in the x-ray tube and the readout circuits in the detector, the acquired images show nonuniform statistics and thus selecting an appropriate image pair from a given image set is important for a stable measurement of NPS. In order to select a good image pair for measuring an accurate normalized NPS (NNPS), a measurement method is proposed based on selecting an image pair from comparing the signal-to-noise ratios, which are obtained from the subtracted image. For the comparison, a commutative relationship as a sufficient condition for the accurate NNPS is considered. For a given image pair, the proposed method can provide a degree of accuracy of the empirical NNPS. For real x-ray images acquired from an indirect radiography detector, the proposed method is tested and shows stable measuring results for a set of images.","PeriodicalId":184587,"journal":{"name":"2016 IEEE Nuclear Science Symposium, Medical Imaging Conference and Room-Temperature Semiconductor Detector Workshop (NSS/MIC/RTSD)","volume":"59 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":"120960854","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.2016.8069885
Zhixiang Zhao, Qiu Huang, T. Sui, Jianfeng Xu, Q. Peng
The Silicon photomultiplier (SiPM) becomes a choice of photon sensors for advanced radiation detector development. However, reading out large-scale SiPM arrays is still a fundamental technical obstacle. We present a new method (named π-PET electronics) to address this issue. Very different from conventional front-end electronics design, the key innovation of the new electronics is to include almost all functions of front-end readout electronics inside a low-cost FPGA. That not only simplifies the analog components and reduce the cost (with only one linear amplifier) but also provides powerful and flexible signal processes to enable applying different algorithms to both enhance the performance and add new real-time dark current measurement and calibration features.
{"title":"A novel electronics for large scale SiPM array readout and advanced PET applications","authors":"Zhixiang Zhao, Qiu Huang, T. Sui, Jianfeng Xu, Q. Peng","doi":"10.1109/NSSMIC.2016.8069885","DOIUrl":"https://doi.org/10.1109/NSSMIC.2016.8069885","url":null,"abstract":"The Silicon photomultiplier (SiPM) becomes a choice of photon sensors for advanced radiation detector development. However, reading out large-scale SiPM arrays is still a fundamental technical obstacle. We present a new method (named π-PET electronics) to address this issue. Very different from conventional front-end electronics design, the key innovation of the new electronics is to include almost all functions of front-end readout electronics inside a low-cost FPGA. That not only simplifies the analog components and reduce the cost (with only one linear amplifier) but also provides powerful and flexible signal processes to enable applying different algorithms to both enhance the performance and add new real-time dark current measurement and calibration features.","PeriodicalId":184587,"journal":{"name":"2016 IEEE Nuclear Science Symposium, Medical Imaging Conference and Room-Temperature Semiconductor Detector Workshop (NSS/MIC/RTSD)","volume":"1 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":"121153190","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.2016.8069415
A. Badano
Publicly available Monte Carlo simulation packages for light transport in scintillator-based x-ray imaging detectors utilize a linear yield model. However, scintillators are known to be non-linear in the lower end of the energy range. Is this assumption reasonable for x-ray imaging simulations? We modified a freely available Monte Carlo package for modeling x-ray scintillators (MANTIS) to compare a linear versus a nonlinear optical yield model. We report simulations in the diagnostic x-ray energy range for a CsI:Tl. To determine the effect of the light yield model on imaging performance, we calculated the distribution of signal outputs characterized by the information or Swank factor. We find that the choice of yield model plays a significant role in the outcome statistics increasing the intensity of lower energy peaks favored by the non-linear model. This observation is confirmed by the results for the Swank factor with larger values for the non-linear models for an increase with respect to the linear model results of 42 and 26% for a high-resolution and a high-light-output model respectively. Our findings indicate that the assumption of linear light yield in Monte Carlo simulations of imaging detectors might introduce a significant bias in the estimates of noise as expressed by the Swank factor. More research is needed to implement realistic nonlinear yield models, to calculate the effect on realistic simulations including x-ray spectra of interest, and to experimentally validate these models.
{"title":"Does energy non-linearity affect noise estimates from Monte Carlo simulations of X-ray imaging detectors?","authors":"A. Badano","doi":"10.1109/NSSMIC.2016.8069415","DOIUrl":"https://doi.org/10.1109/NSSMIC.2016.8069415","url":null,"abstract":"Publicly available Monte Carlo simulation packages for light transport in scintillator-based x-ray imaging detectors utilize a linear yield model. However, scintillators are known to be non-linear in the lower end of the energy range. Is this assumption reasonable for x-ray imaging simulations? We modified a freely available Monte Carlo package for modeling x-ray scintillators (MANTIS) to compare a linear versus a nonlinear optical yield model. We report simulations in the diagnostic x-ray energy range for a CsI:Tl. To determine the effect of the light yield model on imaging performance, we calculated the distribution of signal outputs characterized by the information or Swank factor. We find that the choice of yield model plays a significant role in the outcome statistics increasing the intensity of lower energy peaks favored by the non-linear model. This observation is confirmed by the results for the Swank factor with larger values for the non-linear models for an increase with respect to the linear model results of 42 and 26% for a high-resolution and a high-light-output model respectively. Our findings indicate that the assumption of linear light yield in Monte Carlo simulations of imaging detectors might introduce a significant bias in the estimates of noise as expressed by the Swank factor. More research is needed to implement realistic nonlinear yield models, to calculate the effect on realistic simulations including x-ray spectra of interest, and to experimentally validate these models.","PeriodicalId":184587,"journal":{"name":"2016 IEEE Nuclear Science Symposium, Medical Imaging Conference and Room-Temperature Semiconductor Detector Workshop (NSS/MIC/RTSD)","volume":"26 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":"121023173","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.2016.8069702
C. Grove, C. Eldridge, J. Burns, C. Steer, G. Chapman, A. Lohstroh
This work presents data obtained from an investigation into muon stimulated neutron emission in combination with the technique of muon scattering tomography. Initial measurements in lead of the neutron emission measured a half-life of 56.9 ± 6.63 ns which is three standard deviations lower than expected, with the error primarily attributed to prompt X-ray emission. A hypothetical detector, based on a muon scattering tomography prototype at AWE was used to examine the data expected from an integrated system. A lifetime 81 ± 3 ns was obtained here. Alongside this a portable muon trigger detector has been developed which aims to be implemented in a deployable muon scattering tomography system. The portable detector successfully measures muons to an accuracy of 20%.
{"title":"Neutron spallation to enhance muon scattering tomography","authors":"C. Grove, C. Eldridge, J. Burns, C. Steer, G. Chapman, A. Lohstroh","doi":"10.1109/NSSMIC.2016.8069702","DOIUrl":"https://doi.org/10.1109/NSSMIC.2016.8069702","url":null,"abstract":"This work presents data obtained from an investigation into muon stimulated neutron emission in combination with the technique of muon scattering tomography. Initial measurements in lead of the neutron emission measured a half-life of 56.9 ± 6.63 ns which is three standard deviations lower than expected, with the error primarily attributed to prompt X-ray emission. A hypothetical detector, based on a muon scattering tomography prototype at AWE was used to examine the data expected from an integrated system. A lifetime 81 ± 3 ns was obtained here. Alongside this a portable muon trigger detector has been developed which aims to be implemented in a deployable muon scattering tomography system. The portable detector successfully measures muons to an accuracy of 20%.","PeriodicalId":184587,"journal":{"name":"2016 IEEE Nuclear Science Symposium, Medical Imaging Conference and Room-Temperature Semiconductor Detector Workshop (NSS/MIC/RTSD)","volume":"16 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":"116640628","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：