A5013674426- Radiation Detection and Scintillator Technologies
- Nuclear Physics and Applications
- Nuclear physics research studies
- Medical Imaging Techniques and Applications
- Particle Detector Development and Performance
- Quantum, superfluid, helium dynamics
- Atomic and Subatomic Physics Research
- Particle accelerators and beam dynamics
- Nuclear reactor physics and engineering
- Advanced Chemical Physics Studies
- Particle physics theoretical and experimental studies
- Radiation Therapy and Dosimetry
- X-ray Spectroscopy and Fluorescence Analysis
- Advanced X-ray and CT Imaging
- Atomic and Molecular Physics
- Astronomical and nuclear sciences
- Quantum Chromodynamics and Particle Interactions
- Particle Accelerators and Free-Electron Lasers
- Superconducting Materials and Applications
- High-Energy Particle Collisions Research
- Magnetic confinement fusion research
- Radioactive Decay and Measurement Techniques
- Cold Fusion and Nuclear Reactions
- Nuclear Materials and Properties
- Social Sciences and Policies
University of California System
2024
Valparaiso University
2011-2013
TRIUMF
1995-2007
Simon Fraser University
1989-2005
United States Geological Survey
1991
Virginia Beach Public Library
1991
Denver Federal Center
1991
University of Toronto
1988
University of British Columbia
1978-1986
University of Manitoba
1975-1982
The authors present the results of testing an algorithm for three-dimensional image reconstruction that uses all gamma-ray coincidence events detected by a PET (positron emission tomography) volume imaging scanner. By using two iterations analytic filter-backprojection method, is not constrained requirement spatially invariant detector point spread function, which limits normal techniques. Removing this constraint allows incorporation events, regardless orientation, improves statistical...
A powerful look at the real America, dominated by America's forgotten majority-white working-class men and women who make up 55 percent of voting population
We have developed a simulation to model position encoding multicrystal detectors for positron emission tomography. The is designed treat the interactions of energetic photons in scintillator, geometry array, as well propagation and detection individual scintillation photons. tested with EXACT HR PLUS block detector manufactured by Siemens-CTI. Position energy responses derived from are compared measured ones. Line-spread-functions, four columns crystals, reproduced an accuracy /spl...
The long-lived radioactive nuclide 22Na (t1∕2=2.6yr) is an astronomical observable for understanding the physical processes of oxygen-neon novae. Yields in these events are sensitive to unknown total rate 21Na(p,γ)22Mg reaction. Using a high intensity 21Na beam at TRIUMF−ISAC facility, strengths seven resonances 22Mg, potential astrophysical importance, have been directly measured center mass energies from Ec.m.=200 1103keV. We report results obtained and their respective contributions novae...
The correctness of an analytical simulation for single-scattered gamma rays in positron volume imaging was verified by comparing it to Monte Carlo single scattering. using measured tomograph data. single-scatter extended estimate multiple multiple-scatter showed good agreement with the total object scatter. It is shown that position a source along line response and shape scattering make substantial difference scatter distribution projections. Such projections can be generated much shorter...
<title>Abstract</title> Particle in Cell (PIC) simulation has been used to validate a conceptual design for quasi-spherical, net power, hydrogen plus boron fueled, fusion reactor incorporating high temperature superconducting (HTS) magnets. By burning fully thermalized plasma, our proposed MET6 uses the principles of Magneto-Electrostatic Trap Yushmanov (1980) improve classic Polywell design, resulting predicted power-balance Q ≈ 1.3. Because input power consumed by will barely balances...
Particle in Cell (PIC) simulation has been used to validate a conceptual design for quasi-spherical, net power, hydrogen plus boron-11 fueled, fusion reactor incorporating high temperature superconducting (HTS) magnets. By burning fully thermalized plasma, our proposed MET6 uses the principles of Magneto-Electrostatic Trap Yushmanov (1980) improve classic Polywell design, resulting predicted power-balance Q ≈ 1.3. Because input power consumed by will barely balance waste bremsstrahlung...
The shortcomings of conventional scintillation cameras are analysed theoretically with a view towards improving performance at gamma ray energies above 140 keV. A camera design is proposed which incorporates several new features to obtain good spatial resolution from thicker crystals sodium iodide. Computer simulations show that in addition having efficiency and resolution, the allows parallax error correction (possibly) Compton scattering up 511
The depth-of-interaction effect in block detectors degrades the image resolution commercial PET cameras and impedes natural evolution of smaller, less expensive cameras. A method for correcting measured position each detected gamma ray by measuring its was tested found to recover 38% lost at 7.5 cm radius a tabletop, 50-cm-diameter camera. To obtain desired depth sensitivity, standard were modified simple practical process that is suitable mass production detectors. impact detector...
A review is made of selected recent publications on three-dimensional image reconstruction for PET. new algorithm proposed which designed to fully utilize all emitted gamma rays can be detected in a truncated spherical detector. By such full utilization the should produce images better statistical accuracy than could produced by previously known algorithms.
A tomograph with the PETT VI geometry has been built improvements generally applicable to such devices. In addition improved temperature control, gantry features commercial CsF detectors newer Amperex photomultiplier tubes (PMT's). Much of coincidence support circuitry is an original design, utilizing new "fast" TTL family local DEC 11/23 microprocessor provides for routine diagnostic and reliability checking, acquisition single detector counting rates. Image reconstruction display performed...
The $^{4}\mathrm{He}$($p$,$2p$)$^{3}\mathrm{H}$ reaction has been studied at 250, 350, and 500 MeV using coplanar symmetric asymmetric geometries. data are presented as energy-sharing spectra, angular distributions, quasifree distributions. A comparison with distorted wave impulse approximation calculations indicates reasonable agreement for small recoil momenta ($q\ensuremath{\lesssim}150$ MeV/c). For larger momenta, the distorted-wave increasingly underestimate data. discrepancies...
The authors evaluate and compare two 2-D array detectors for positron emission tomography (PET). Both consisted of an 8*8 small BGO crystals coupled to a 2*2 photomultiplier tubes. depth the was 3 cm in one detector 2 other. 2-cm is superior terms material costs, energy resolution per crystal, its ability clearly identify crystal containing primary interaction. A flexible robust algorithm presented identification such detectors. prospect obtaining still better spatial from block detectors,...
An analytic three-dimensional image-reconstruction algorithm that can utilize the cross-plane gamma rays detected by a wide solid-angle PET (positron-emission tomography) system is presented. Unlike current algorithms, it does not use Fourier transform methods, although mathematical equivalence to methods proved. The results of implementing are briefly discussed. extension all measured discussed.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML"...
A method is presented for correcting PET images the blurring caused by variations in depth-of-interaction position-sensitive gamma ray detectors. The uses an empirically determined, tabulated relationship between and most probable pulse-height to estimate unknown depth from measured each detected ray. In case of one fine-cut 50x50x30 mm BGO block detector, shown improve detector resolution 25%, averaged over 50x50 face, geometry corresponding detection at edge field-of-view. Strengths...
The authors have developed a method of effecting depth-of-interaction sensitivity for PET detectors. It exploits significant difference in the index refraction between adjacent scintillator segments and compound optically coupling them, to induce discrete resolved photopeak pulse heights depending on segment interaction /spl gamma/-rays. approach was put first experimental test by manufacturing two prototypes with LSO crystals dimensions 4/spl times/4/spl times/30 mm 2.5/spl times/2.5/spl...
The characteristics of YAlO/sub 3/:Ce (YALO) used as a fast scintillation detector with high density (5.35 gm/cm/sup 3/) and light yield were investigated compared those other materials. decay the could be described by sum two exponentials constants 31 ns 246 contributing 98% 2% to total yield, respectively. 19700 photons/MeV was measured comparing number photoelectrons produced in YAlO BGO under same conditions. energy resolution at gamma ray 511 keV 6.7% for 4.0*8.0*25.0 mm/sup 3/ sample....
A whole-body positron-emission tomography (PET) machine based on a novel type of large-area sodium iodide (NaI) detector is being designed. Monte Carlo computer simulations have been used to compare some the performance parameters tomograph detectors similar conventional small-crystal machines. Three different prototypes constructed, and many tests performed, including measurements transverse spatial resolution, depth-of-interaction energy time high-counting-rate capabilities. The simulation...
Attenuation correction in PET performed by the transmission measurement method provides accurate compensation but increases image noise. Transmission profile filtering is evaluated terms of noise reduction as a trade-off against systematic error introduced filter itself. Phantom measurements on UBC/TRIUMF PETT VI tomograph are used to evaluate performance. It found that with Gaussian 12.5 mm FWHM reduces variance due profiles factor 15.