Download or read book Development and Evaluation of Real Time Volumetric Compton Gamma Ray Imaging written by Ross Barnowski Barnowski and published by . This book was released on 2016 with total page 177 pages. Available in PDF, EPUB and Kindle. Book excerpt: An approach to gamma-ray imaging has been developed that enables near real-time volumetric (3D) imaging of unknown environments thus improving the utility of gamma-ray imaging for source-search and radiation mapping applications. The approach, herein dubbed scene data fusion (SDF), is based on integrating mobile radiation imagers with real-time tracking and scene reconstruction algorithms to enable a mobile mode of operation and 3D localization of gamma-ray sources. The real-time tracking allows the imager to be moved throughout the environment or around a particular object of interest, obtaining the multiple perspectives necessary for standoff 3D imaging. A 3D model of the scene, provided in real-time by a simultaneous localization and mapping (SLAM) algorithm, can be incorporated into the image reconstruction reducing the reconstruction time and improving imaging performance. The SDF concept is demonstrated in this work with a Microsoft Kinect RGB-D sensor, a real-time SLAM solver, and two different mobile gamma-ray imaging platforms. The first is a cart-based imaging platform known as the Volumetric Compton Imager (VCI), comprising two 3D position-sensitive high purity germanium (HPGe) detectors, exhibiting excellent gamma-ray imaging characteristics, but with limited mobility due to the size and weight of the cart. The second system is the High Efficiency Multimodal Imager (HEMI) a hand-portable gamma-ray imager comprising 96 individual cm$^{3}$ CdZnTe crystals arranged in a two-plane, active-mask configuration. The HEMI instrument has poorer energy and angular resolution than the VCI, but is truly hand-portable, allowing the SDF concept to be tested in multiple environments and for more challenging imaging scenarios. An iterative algorithm based on Compton kinematics is used to reconstruct the gamma-ray source distribution in all three spatial dimensions. Each of the two mobile imaging systems are used to demonstrate SDF for a variety of scenarios, including general search and mapping scenarios with several point gamma-ray sources over the range of energies relevant for Compton imaging. More specific imaging scenarios are also addressed, including directed search and object interogation scenarios. Finally, the volumetric image quality is quantitatively investigated with respect to the number of Compton events acquired during a measurement, the list-mode uncertainty of the Compton cone data, and the uncertainty in the pose estimate from the real-time tracking algorithm. SDF advances the real-world applicability of gamma-ray imaging for many search, mapping, and verification scenarios by improving the tractiblity of the gamma-ray image reconstruction and providing context for the 3D localization of gamma-ray sources within the environment in real-time.

Download or read book Design and Evaluation of Gamma Imaging Systems of Compton and Hybrid Cameras written by Yuxin Feng and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: For medical applications in proton therapy, a Compton camera system to image the gamma-ray emission during treatment was designed and investigated. Gamma rays and X-rays emitted during treatment illustrate the energy deposition along the path of the proton beams and provide an opportunity for online dose verification. This Compton camera is designed to be capable of imaging gamma rays in 3D and is one of the candidates for imaging gamma emission during the treatment of proton therapy beside of the approach of positron emission tomography. In order to meet the requirement for spatial resolution of approximately 5 mm or less to meaningfully verify the dose via imaging gamma rays of 511 keV to 2 MeV, position sensing techniques with pixilated LaBr3(Ce) crystal were applied in each detector. The pixilated LaBr3 (Ce) crystal was used in both the scattering and absorbing detectors. Image reconstruction algorithms of OS-EML were applied to obtain 3D images.

Download or read book Evaluation of Errors Due to Compton Scattering in Gamma ray Emission Imaging written by and published by . This book was released on 1983 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A set of computer simulation programs were developed to aid in the design of new instrumentation and in the design and evaluation of algorithms for scatter correction in positron emission computed tomography. 14 references, 15 figures, 3 tables. (ACR).

Download or read book Gamma Ray Imaging written by Junwei Du and published by Springer Nature. This book was released on 2023-09-12 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book will provide readers with a good overview of some of the most recent advances in the field of detector technology for gamma-ray imaging, especially as it pertains to new applications. There will be a good mixture of general chapters in both technology and applications in medical imaging and industrial testing. The book will have an in-depth review of the research topics from world-leading specialists in the field. The conversion of the gamma-ray signal into analog/digital value will be covered in some chapters. Some would also provide a review of CMOS chips for gamma-ray image sensors.

Download or read book A Compton Camera for Low Energy Gamma Ray Imaging in Nuclear Medicine Applications written by James Walter LeBlanc and published by . This book was released on 1999 with total page 396 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Development of a Compton Camera for the Imaging of Gamma Rays in the Energy Range 0 662 MeV to 6 130 MeV written by Martin Jones and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Development of Advanced Imaging Algorithms and Representations for Compton Gamma ray Cameras written by Christian Van Ouellet and published by . This book was released on 2018 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Development of a Compton Camera for the Imaging of Gamma Rays in the Energy Range 0 662 MeV to 6 130 MeV written by Martin Paul Jones and published by . This book was released on 2013 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Evaluation of Errors Due to Compton Scattering in Gamma ray Emission Imaging written by Michael Francis Bruno and published by . This book was released on 1983 with total page 150 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Application of Advanced Gamma Ray Detection Concepts Combined with Real time Compton Suppression for Nondestructive Gamma Ray Characterization of Remote handled Waste written by Michael McIlwain and published by . This book was released on 2004 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nondestructive gamma ray characterization of remote-handled waste is significantly complicated by the presence of Compton scattering in the detector and waste matrix produced by the intense cesium gamma ray. This research seeks to understand the photophysics of a new type of inorganic scintillation gamma ray detector, optimize the combination of this gamma ray detector with a Compton guard detector, develop new Monte Carlo solution algorithms for modeling Compton scattering in the waste, and to model the real time intensity of cesium produced Compton scattering. A successful research program will provide the fundamental information needed to design and develop advanced Compton spectrometers for assay of remote handled waste and new higher sensitivity spectrometers for environmental measurements.

Download or read book Implementation and Characterization of the Data Acquisition System of a Compton Camera for Prompt Gamma Imaging in Protontherapy written by Cairo Pimenta Cheble Caplan and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hadrontherapy uses a beam of charged particles (protons or carbon ions) to destroy tumour cells. Compared to conventional radiotherapy hadrontherapy represents a promising technique to treat cancer because of its concentrated dose delivery within the Bragg peak. Monitoring of dose delivery can thus be addressed by verifying the range of the beam particles.CLaRyS, which stands for online control of hadrontherapy by secondary radiation, is a project regrouping several laboratories that aims at improving dose delivery control by imaging the emission of prompt-gamma rays issued from inelastic collisions of the beam particles with target nuclei. This requires to detect prompt-gamma rays using either a mechanical or the electronic collimation resulting from the Compton interactions of the gamma rays in a scatterer.As part of this development, a high-performance and compact Back-End (BE) electronics was developed at CPPM to perform data acquisition from the detectors through 34 optical links of 3 Gb/s. Data are packed and sent to a PC on a 1 Gb/s Ethernet link, guaranteeing 300 Mb/s throughput as specified for the Compton camera by Monte Carlo simulations for a beam intensity of 10 power of 8 proton/s. My thesis work comprised the development of the FPGA firmware for the BE electronics of CLaRyS, while contributing to the development and evaluation of its detection system. Measurements with the collimated camera and beam hodoscope were performed on the 65 MeV proton beam line of the Mediterranean Protontherapy Institute in Nice.

Download or read book Electron Trajectory Reconstruction for Advanced Compton Imaging of Gamma Rays written by Brian Christopher Plimley and published by . This book was released on 2014 with total page 191 pages. Available in PDF, EPUB and Kindle. Book excerpt: Gamma-ray imaging is useful for detecting, characterizing, and localizing sources in a variety of fields, including nuclear physics, security, nuclear accident response, nuclear medicine, and astronomy. Compton imaging in particular provides sensitivity to weak sources and good angular resolution in a large field of view. However, the photon origin in a single event sequence is normally only limited to the surface of a cone. If the initial direction of the Compton-scattered electron can be measured, the cone can be reduced to a cone segment with width depending on the uncertainty in the direction measurement, providing a corresponding increase in imaging sensitivity. Measurement of the electron's initial direction in an efficient detection material requires very fine position resolution due to the electron's short range and tortuous path. A thick (650 [mu]m), fully-depleted charge-coupled device (CCD) developed for infrared astronomy has 10.5-[mu]m position resolution in two dimensions, enabling the initial trajectory measurement of electrons of energy as low as 100 keV. This is the first time the initial trajectories of electrons of such low energies have been measured in a solid material. In this work, the CCD's efficacy as a gamma-ray detector is demonstrated experimentally, using a reconstruction algorithm to measure the initial electron direction from the CCD track image. In addition, models of fast electron interaction physics, charge transport and readout were used to generate modeled tracks with known initial direction. These modeled tracks allowed the development and refinement of the reconstruction algorithm. The angular sensitivity of the reconstruction algorithm is evaluated extensively with models for tracks below 480 keV, showing a FWHM as low as 20° in the pixel plane, and 30° RMS sensitivity to the magnitude of the out-of-plane angle. The measurement of the trajectories of electrons with energies as low as 100 keV have the potential to make electron track Compton imaging an effective means of reducing image background for photons of energy as low as 500 keV, or even less. The angular sensitivity of the reconstruction algorithm was also evaluated experimentally, by measuring electron tracks in the CCD in coincidence with the scattered photon in a germanium double-sided strip detector. By this method, electron tracks could be measured with the true initial direction known to within 3° FWHM, and the angular response of the algorithm compared to the known direction. The challenge of this experiment lay in the low geometric efficiency for photons scattering into the germanium, the poor time resolution in the current CCD implementation, and the resulting signal-to-background ratio of about 10−4 for photons scattered from the CCD into the germanium detector. Nonetheless, 87 events were measured in the FWHM of the total energy deposited and the angular resolution measure, with electron tracks between 160 keV and 360 keV in energy. The electron tracks from true coincident event sequences showed a FWHM in the pixel plane of 23°, and excellent agreement with the distribution calculated with models, with likelihood p-values of 0.44 and 0.73. Thus, the models used for the more thorough evaluation of angular sensitivities are shown to be consistent with the measured tracks from true coincident event sequences.

Download or read book Gamma ray Detection and Compton Camera Image Reconstruction with Application to Hadron Therapy written by Mirela Frandes and published by . This book was released on 2010 with total page 109 pages. Available in PDF, EPUB and Kindle. Book excerpt: A novel technique for radiotherapy - hadron therapy - irradiates tumors using a beam of protons or carbon ions. Hadron therapy is an effective technique for cancer treatment, since it enables accurate dose deposition due to the existence of a Bragg peak at the end of particles range. Precise knowledge of the fall-off position of the dose with millimeters accuracy is critical since hadron therapy proved its efficiency in case of tumors which are deep-seated, close to vital organs, or radio-resistant. A major challenge for hadron therapy is the quality assurance of dose delivery during irradiation. Current systems applying positron emission tomography (PET) technologies exploit gamma rays from the annihilation of positrons emitted during the beta decay of radioactive isotopes. However, the generated PET images allow only post-therapy information about the deposed dose. In addition, they are not in direct coincidence with the Bragg peak. A solution is to image the complete spectrum of the emitted gamma rays, including nuclear gamma rays emitted by inelastic interactions of hadrons to generated nuclei. This emission is isotropic, and has a spectrum ranging from 100 keV up to 20 MeV. However, the measurement of these energetic gamma rays from nuclear reactions exceeds the capability of all existing medical imaging systems. An advanced Compton scattering detection method with electron tracking capability is proposed, and modeled to reconstruct the high-energy gamma-ray events. This Compton detection technique was initially developed to observe gamma rays for astrophysical purposes. A device illustrating the method was designed and adapted to Hadron Therapy Imaging (HTI). It consists of two main sub-systems: a tracker where Compton recoiled electrons are measured, and a calorimeter where the scattered gamma rays are absorbed via the photoelectric effect. Considering a hadron therapy scenario, the analysis of generated data was performed, passing trough the complete detection chain from Monte Carlo simulations to reconstruction of individual events, and finally to image reconstruction. A list-mode Maximum-Likelihood Expectation-Maximization (MLEM) algorithm was adopted to perform image reconstruction in conjunction with the imaging response, which has to depict the complex behavior of the detector. Modeling the imaging response requires complex calculations, considering the incident angle, all measured energies, the Compton scatter angle in the first interaction, the direction of scattered electron (when measured). In the simplest form, each event response is described by Compton cone profiles. The shapes of the profiles are approximated by 1D Gaussian distributions. A strong correlation was observed between pattern of the reconstructed high-energy gamma events, and location of the Bragg peak. The performance of the imaging technique illustrated by the HTI is a function of the detector performance in terms of detection efficiency, spatial and energy resolution, acquisition time, and the algorithms used to reconstruct the gamma-ray activity. Thus beside optimizations of the imaging system, the applied imaging algorithm has a high influence on the final reconstructed images. The HTI reconstructed images are corrupted by noise due to the low photon counts recorded, the uncertainties induced by finite energy resolution, Doppler broadening, the limited model used to estimate the imaging response, and the artifacts generated when iterating the MLEM algorithm. This noise is spatially varying and signal-dependent, representing a major obstacle for information extraction. Thus image de-noising techniques were investigated. AWavelet based multi-resolution strategy of list-mode MLEMRegularization (WREM) was developed to reconstruct Compton images. At each iteration, a threshold-based processing step was integrated. The noise variance was estimated at each scale of the wavelet decomposition as the median value of the coefficients from the high-frequency sub-bands. This approach allowed to obtain a stable behavior of the iterative algorithm, presenting lower mean-squared error, and improved contrast recovery ratio.

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 704 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book THE COMPTON GAMMA RAY OBSERVATORY written by N. Gehrels and published by . This book was released on 1991 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Development of Gamma Ray Compton Imager Using Room Temperature 3 D Position Sensitive Semiconductor Detectors written by and published by . This book was released on 2003 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: During the three years of this project, two 3-dimensional position sensitive CdZnTe spectrometers were upgraded in collaboration with Johns Hopkins University Applied Physics Laboratory. A prototype Compton-scattering gamma-ray imager was assembled using the two upgraded CdZnTe detectors. The performance of both gamma-ray spectrometers were individually tested. The angular resolution and detection sensitivity of the imaging system were measured using both a point and a line-shaped 137 Cs radiation source. The measurement results are consistent with that obtained from Monte-Carlo simulations performed during the early phase of the project.

Download or read book COMBINED MEASUREMENTS WITH THREE DIMENSIONAL DESIGN INFORMATION VERIFICATION SYSTEM AND GAMMA RAY IMAGING A COLLABORATIVE EFFORT BETWEEN OAK RIDGE NATIONAL LABORATORY LAWRENCE LIVERMORE NATIONAL LABORATORY AND THE JOINT RESEARCH CENTER AT ISPRA written by S. Smith and published by . This book was released on 2006 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: Oak Ridge National Laboratory (ORNL) and Lawrence Livermore National Laboratory (LLNL) have jointly performed tests to demonstrate combined measurements with a three-dimensional (3D) design information verification (DIV) system and a gamma-ray imager for potential safeguard applications. The 3D DIV system was made available by the European Commission's Joint Research Center to ORNL under a collaborative project between the U.S. Department of Energy and the European Atomic Energy Community (EURATOM). The system is able to create 3D maps of rooms and objects and of identifying changes in positions and modifications with a precision on the order of millimeters. The gamma ray imaging system consists of a 4{pi} field-of-view Compton imaging system which has two fully operational DSSD (Double-Sided Segment Detector) High-Purity Germanium (HPGe) detectors developed at LLNL. The Compton imaging instrument not only provides imaging capabilities, but provides excellent energy resolution which enables the identification of radioisotopes and nuclear materials. Joint Research Center was responsible to merge gamma-ray images with the 3D range maps. The results of preliminary first measurements performed at LLNL demonstrate, for the first time, mapping of panoramic gamma-ray images into 3D range data.