Nuclear Scene Data Fusion (SDF), implemented in the Localization and Mapping Platform (LAMP) fuse... more Nuclear Scene Data Fusion (SDF), implemented in the Localization and Mapping Platform (LAMP) fuses three-dimensional (3D), real-time volumetric reconstructions of radiation sources with contextual information (e.g. LIDAR, camera, etc.) derived from the environment around the detector system. This information, particularly when obtained in real time, may be transformative for applications, including directed search for lost or stolen sources, consequence management after the release of radioactive materials, or contamination avoidance in security-related or emergency response scenarios. 3D reconstructions enabled by SDF localize contamination or hotspots to specific areas or objects, providing higher resolution over larger areas than conventional 2D approaches, and enabling more efficient planning and response, particularly in complex 3D environments. In this work, we present the expansion of these gamma-ray mapping concepts to neutron source localization. Here we integrate LAMP with...
PURPOSE To evaluate and characterize a multi-slit collimated imaging system for use in prompt gam... more PURPOSE To evaluate and characterize a multi-slit collimated imaging system for use in prompt gamma range verification of proton therapy. METHODS Acrylic (PMMA) targets were irradiated with a 50 MeV proton beam. With the collimator placed 13 cm from the beam axis, photons of energy from 2-7 MeV were measured. Image reconstruction provided 2-dimensional distribution of gamma rays. Estimated Bragg peak location was compared with 1-dimensional profiles of photon images. Shifts in Bragg peak were simulated by physically moving the targets in 1 mm increments. RESULTS The imaging system measured prompt gamma emissions resulting from a 50 MeV proton beam, at currents up to 2 nA, incident on a PMMA target. Overall system detection efficiency was approximately 2.6×10-5 gamma/proton. With delivery of 1×1011 protons, shifts of 1 mm in the target location were detected in 2D prompt gamma images and 1D profiles. With delivery of 1×108 protons, shifts of approximately 3 mm were detectable. CONCLUSION This work has characterized the performance of a prototype multi-slit collimated imaging system. The system can produce 2D images of prompt gamma distributions and detect shifts in Bragg peak location down to 1 mm. These results encourage further development and optimization of the system for clinical proton beam applications. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number: DENA0000979 through the Nuclear Science and Security Consortium.
2018 IEEE Nuclear Science Symposium and Medical Imaging Conference Proceedings (NSS/MIC), 2018
Range uncertainty in proton therapy has a significant impact on the utilization and efficacy of t... more Range uncertainty in proton therapy has a significant impact on the utilization and efficacy of the treatment modality. Several methods are under investigation to verify proton range by the detection of secondary emissions, with many studies focused on the use of prompt gamma-ray imaging (PGI) as a means to determine the Bragg peak location. This work introduces a new system and method of PGI using a multi-knife-edge slit collimator and detector. Initial measurements using 50 MeV protons demonstrated the ability of the system to provide 2-dimensional prompt gamma-ray (PG) distributions. A Bragg peak localization precision of 1 mm (2σ) was achieved with delivery of (1.7 ± 0.8) x 108 protons into a PMMA target from an 8 cm standoff distance, suggesting the ability of the system to detect relative shifts in proton range while delivering fewer protons than used in a typical treatment fraction. Additionally, the absolute position of the Bragg peak was identified to within 1.6 mm (2σ) with 5.6 x 1010 protons delivered. The initial results are promising and warrant further investigation and system optimization for clinical implementation.
Neutron double scatter imaging exploits the kinematics of neutron elastic scattering to enable em... more Neutron double scatter imaging exploits the kinematics of neutron elastic scattering to enable emission imaging of neutron sources. Due to the relatively low coincidence detection efficiency of fast neutrons in organic scintillator arrays, imaging efficiency for double scatter cameras can also be low. One method to realize significant gains in neutron coincidence detection efficiency is to develop neutron double scatter detectors which employ monolithic blocks of organic scintillator, instrumented with photosensor arrays on multiple faces to enable 3D position and multi-interaction time pickoff. Silicon photomultipliers (SiPMs) have several advantageous characteristics for this approach, including high photon detection efficiency (PDE), good single photon time resolution (SPTR), high gain that translates to single photon counting capabilities, and ability to be tiled into large arrays with high packing fraction and photosensitive area fill factor. However, they also have a tradeoff ...
The High Efficiency Multimode Imager (HEMI) is an instrument to detect, locate, and spectroscopic... more The High Efficiency Multimode Imager (HEMI) is an instrument to detect, locate, and spectroscopically characterize radioactive sources with gamma-ray emissions at long-range standoff distances. HEMI consists of modular cubic-centimeter coplanar-grid CdZnTe detector elements configured in a two-plane array that allows for both Compton scattering and coded aperture imaging. Measurements and simulations have been performed using a variety of radioactive sources
Networked detector systems can be deployed in urban environments to aid in the detection and loca... more Networked detector systems can be deployed in urban environments to aid in the detection and localization of radiological and/or nuclear material. However, effectively responding to and interpreting a radiological alarm using spec- troscopic data alone may be hampered by a lack of situational awareness, particularly in complex environments. This study investigates the use of LiDAR and streaming video to enable real-time object detection and tracking, and the fusion of this tracking information with radiological data for the purposes of enhanced situational awareness and increased detection sensitiv- ity. This work presents an object detection, tracking, and novel source-object attribution analysis that is capable of operating in real-time. By implementing this analysis pipeline on a custom developed system that comprises a static 2 × 4 × 16 inch NaI(Tl) detector co-located with a 64-beam LiDAR and 4 monocular cameras, we demonstrate the ability to accurately correlate trajectories f...
Real-time, meter-resolution gamma-ray mapping is relevant in the detection and mapping of radiolo... more Real-time, meter-resolution gamma-ray mapping is relevant in the detection and mapping of radiological materials, and for applications ranging from nuclear decommissioning, waste management, and environmental remediation to homeland security, emergency response, and international safeguards. We present the Localization and Mapping Platform (LAMP) as a modular, contextual and radiation detector sensor suite, which performs gamma-ray mapping in three dimensions (3-D) and in real time, onboard an unmanned aerial vehicle (UAV) or in a man-portable configuration. The deployment of an unmanned aerial system (UAS) for gamma-ray mapping can be advantageous, as the UAS provides a means of measuring large areas efficiently and improving accessibility to some environments, such as multi-story structures. In addition, it is possible to increase measurement robustness through autonomous navigation, and to reduce radiation exposure to users as a result of the remote measurement. LAMP enables mete...
The ability to map and estimate the activity of radiological source distributions in unknown thre... more The ability to map and estimate the activity of radiological source distributions in unknown three-dimensional environments has applications in the prevention and response to radiological accidents or threats as well as the enforcement and verification of international nuclear non-proliferation agreements. Such a capability requires well-characterized detector response functions, accurate time-dependent detector position and orientation data, a digitized representation of the surrounding 3D environment, and appropriate image reconstruction and uncertainty quantification methods. We have previously demonstrated 3D mapping of gamma-ray emitters with free-moving detector systems on a relative intensity scale using a technique called Scene Data Fusion (SDF). Here we characterize the detector response of a multi-element gamma-ray imaging system using experimentally benchmarked Monte Carlo simulations and perform 3D mapping on an absolute intensity scale. We present experimental reconstru...
Nuclear Scene Data Fusion (SDF), implemented in the Localization and Mapping Platform (LAMP) fuse... more Nuclear Scene Data Fusion (SDF), implemented in the Localization and Mapping Platform (LAMP) fuses three-dimensional (3D), real-time volumetric reconstructions of radiation sources with contextual information (e.g. LIDAR, camera, etc.) derived from the environment around the detector system. This information, particularly when obtained in real time, may be transformative for applications, including directed search for lost or stolen sources, consequence management after the release of radioactive materials, or contamination avoidance in security-related or emergency response scenarios. 3D reconstructions enabled by SDF localize contamination or hotspots to specific areas or objects, providing higher resolution over larger areas than conventional 2D approaches, and enabling more efficient planning and response, particularly in complex 3D environments. In this work, we present the expansion of these gamma-ray mapping concepts to neutron source localization. Here we integrate LAMP with...
PURPOSE To evaluate and characterize a multi-slit collimated imaging system for use in prompt gam... more PURPOSE To evaluate and characterize a multi-slit collimated imaging system for use in prompt gamma range verification of proton therapy. METHODS Acrylic (PMMA) targets were irradiated with a 50 MeV proton beam. With the collimator placed 13 cm from the beam axis, photons of energy from 2-7 MeV were measured. Image reconstruction provided 2-dimensional distribution of gamma rays. Estimated Bragg peak location was compared with 1-dimensional profiles of photon images. Shifts in Bragg peak were simulated by physically moving the targets in 1 mm increments. RESULTS The imaging system measured prompt gamma emissions resulting from a 50 MeV proton beam, at currents up to 2 nA, incident on a PMMA target. Overall system detection efficiency was approximately 2.6×10-5 gamma/proton. With delivery of 1×1011 protons, shifts of 1 mm in the target location were detected in 2D prompt gamma images and 1D profiles. With delivery of 1×108 protons, shifts of approximately 3 mm were detectable. CONCLUSION This work has characterized the performance of a prototype multi-slit collimated imaging system. The system can produce 2D images of prompt gamma distributions and detect shifts in Bragg peak location down to 1 mm. These results encourage further development and optimization of the system for clinical proton beam applications. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number: DENA0000979 through the Nuclear Science and Security Consortium.
2018 IEEE Nuclear Science Symposium and Medical Imaging Conference Proceedings (NSS/MIC), 2018
Range uncertainty in proton therapy has a significant impact on the utilization and efficacy of t... more Range uncertainty in proton therapy has a significant impact on the utilization and efficacy of the treatment modality. Several methods are under investigation to verify proton range by the detection of secondary emissions, with many studies focused on the use of prompt gamma-ray imaging (PGI) as a means to determine the Bragg peak location. This work introduces a new system and method of PGI using a multi-knife-edge slit collimator and detector. Initial measurements using 50 MeV protons demonstrated the ability of the system to provide 2-dimensional prompt gamma-ray (PG) distributions. A Bragg peak localization precision of 1 mm (2σ) was achieved with delivery of (1.7 ± 0.8) x 108 protons into a PMMA target from an 8 cm standoff distance, suggesting the ability of the system to detect relative shifts in proton range while delivering fewer protons than used in a typical treatment fraction. Additionally, the absolute position of the Bragg peak was identified to within 1.6 mm (2σ) with 5.6 x 1010 protons delivered. The initial results are promising and warrant further investigation and system optimization for clinical implementation.
Neutron double scatter imaging exploits the kinematics of neutron elastic scattering to enable em... more Neutron double scatter imaging exploits the kinematics of neutron elastic scattering to enable emission imaging of neutron sources. Due to the relatively low coincidence detection efficiency of fast neutrons in organic scintillator arrays, imaging efficiency for double scatter cameras can also be low. One method to realize significant gains in neutron coincidence detection efficiency is to develop neutron double scatter detectors which employ monolithic blocks of organic scintillator, instrumented with photosensor arrays on multiple faces to enable 3D position and multi-interaction time pickoff. Silicon photomultipliers (SiPMs) have several advantageous characteristics for this approach, including high photon detection efficiency (PDE), good single photon time resolution (SPTR), high gain that translates to single photon counting capabilities, and ability to be tiled into large arrays with high packing fraction and photosensitive area fill factor. However, they also have a tradeoff ...
The High Efficiency Multimode Imager (HEMI) is an instrument to detect, locate, and spectroscopic... more The High Efficiency Multimode Imager (HEMI) is an instrument to detect, locate, and spectroscopically characterize radioactive sources with gamma-ray emissions at long-range standoff distances. HEMI consists of modular cubic-centimeter coplanar-grid CdZnTe detector elements configured in a two-plane array that allows for both Compton scattering and coded aperture imaging. Measurements and simulations have been performed using a variety of radioactive sources
Networked detector systems can be deployed in urban environments to aid in the detection and loca... more Networked detector systems can be deployed in urban environments to aid in the detection and localization of radiological and/or nuclear material. However, effectively responding to and interpreting a radiological alarm using spec- troscopic data alone may be hampered by a lack of situational awareness, particularly in complex environments. This study investigates the use of LiDAR and streaming video to enable real-time object detection and tracking, and the fusion of this tracking information with radiological data for the purposes of enhanced situational awareness and increased detection sensitiv- ity. This work presents an object detection, tracking, and novel source-object attribution analysis that is capable of operating in real-time. By implementing this analysis pipeline on a custom developed system that comprises a static 2 × 4 × 16 inch NaI(Tl) detector co-located with a 64-beam LiDAR and 4 monocular cameras, we demonstrate the ability to accurately correlate trajectories f...
Real-time, meter-resolution gamma-ray mapping is relevant in the detection and mapping of radiolo... more Real-time, meter-resolution gamma-ray mapping is relevant in the detection and mapping of radiological materials, and for applications ranging from nuclear decommissioning, waste management, and environmental remediation to homeland security, emergency response, and international safeguards. We present the Localization and Mapping Platform (LAMP) as a modular, contextual and radiation detector sensor suite, which performs gamma-ray mapping in three dimensions (3-D) and in real time, onboard an unmanned aerial vehicle (UAV) or in a man-portable configuration. The deployment of an unmanned aerial system (UAS) for gamma-ray mapping can be advantageous, as the UAS provides a means of measuring large areas efficiently and improving accessibility to some environments, such as multi-story structures. In addition, it is possible to increase measurement robustness through autonomous navigation, and to reduce radiation exposure to users as a result of the remote measurement. LAMP enables mete...
The ability to map and estimate the activity of radiological source distributions in unknown thre... more The ability to map and estimate the activity of radiological source distributions in unknown three-dimensional environments has applications in the prevention and response to radiological accidents or threats as well as the enforcement and verification of international nuclear non-proliferation agreements. Such a capability requires well-characterized detector response functions, accurate time-dependent detector position and orientation data, a digitized representation of the surrounding 3D environment, and appropriate image reconstruction and uncertainty quantification methods. We have previously demonstrated 3D mapping of gamma-ray emitters with free-moving detector systems on a relative intensity scale using a technique called Scene Data Fusion (SDF). Here we characterize the detector response of a multi-element gamma-ray imaging system using experimentally benchmarked Monte Carlo simulations and perform 3D mapping on an absolute intensity scale. We present experimental reconstru...
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