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Since Compton imaging technology was first introduced about 40 years ago, it has been applied to many fields such as astrophysics, industrial and medical application. In the early days, Compton camera started to be used to search for signals from space in which the high energy radiation comes from point sources. The application in astrophysics was followed by the investigation for nuclear material...
Improving system sensitivity without sacrificing imaging resolution is the key to improving the performance of cardiac SPECT imaging. This sensitivity increase is needed for reducing imaging time, or radiation dose, and/or motion artifacts for clinical imaging studies, as well as for exploration of new clinical applications. In addition, attenuation correction is necessary to yield quantitative information...
We developed a motorized variable angle slant-hole collimator (VASH) for a breast-specific gamma imaging detector. The collimator system consists of a stack of 48 tungsten sheets, four wedge blocks, and two motorized actuators for moving the wedge blocks. User controlled shearing of the stack of tungsten sheets can provide multiple projection angles allowing the implementation of limited angle tomography...
The existing SPECT system for nuclear cardiac imaging suffered from low sensitivity or high cost. In this study we implemented a novel design of the stationary dedicated cardiac SPECT combined with multi-pinhole collimators based on the clinical dual-head scanner with low cost. Previous simulation study has demonstrated the feasibility of the design. Accurate geometry calibration was implemented for...
Pixelated direct-conversion detectors are poised to replace scintillators in single photon emission computed tomography (SPECT) cameras with pixel-matching parallel-hole collimators, to compensate for lost resolution while yielding higher sensitivity. However, smaller pixel sizes to improve resolution leads to increased inter-crystal signal sharing, resulting in a drop in sensitivity. It is, therefore,...
Thallium-bromide (TlBr) is currently under investigation as an alternative room-temperature semiconductor gamma-ray spectrometer due to its favorable material properties. Previous work has shown that 5 mm thick pixelated TlBr detectors can achieve sub 1% FWHM energy resolution at 662 keV. However, these results are mostly limited to −20 °C operation. In addition to good electron mobility, some TlBr...
We are developing an improved gamma camera for molecular breast imaging (MBI) that allows tomographic imaging and improved signal-to-noise over conventional planar methods. We have built a novel gamma camera for MBI that utilizes limited angle tomography, similar to x-ray tomosynthesis, to generate images with depth information and improved signal-to-noise. A unique feature of the gamma tomosynthesis...
Previously, we proposed an inexpensive method to improve the performance of the existing general-purpose dual-camera SPECT systems for brain imaging with I-123 (DaTscan) by using a specifically designed multi-pinhole (MPH) collimator on one of the detector heads. We present here our preliminary work investigating the downscatter of the low-abundance high-energy photons of I-123 for our MPH collimator...
We have developed a SPECT gamma photon ray-tracing method based on the SolidWorksTM stereolithography (.STL) file format that models penetration, scatter, and fluorescence in the design work flow[1]. With this powerful tool, now we are able to model various kinds of novel SPECT systems including those with moving collimators. In this work, the configuration of a rotating-slit aperture in combination...
This work is to develop a gamma-ray/neutron dual-particle imager, based on Rotating Modulation Collimators (RMC) and Pulse Shape Discrimination (PSD)-capable scintillators, for the nuclear security and safeguard application. We started with performing fundamental simulations on the RMC, to optimize the collimator design and the computing time for the Monte Carlo simulation. We obtained batches of...
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