David Sowards-Emmerd

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Circular cone-beam computed tomography (CBCT) with a tangentially offset flat-panel X-ray detector offers a large CT field-of-view (FoV) with a relatively small detector. It is used in practice, e.g., for target imaging in image-guided radiotherapy or for localization and attenuation correction in SPECT/CT imaging. The X-ray projections, acquired on a(More)
Using survey data, we have re-evaluated the correlation of flat spectrum radio sources with EGRET sources in the Northern sky. A likelihood analysis incorporating the radio and X-ray properties and the γ-ray source localization is used to gauge the reliability of associations and to search for counterparts of previously unidentified EGRET sources. Above(More)
The new Brightview XCT system uses a flat-panel detector to perform CBCT imaging for attenuation correction and localization. Features include a small footprint due to an offset-detector geometry, advanced scatter correction — both software and hardware — isotropic voxels, and GPU-accelerated reconstruction. System performance characteristics(More)
In preparation for GLAST, we have compiled a sample of blazar candidates to increase the pool of well studied AGN from which GLAST counterparts will be drawn. Sources were selected with our Figure of Merit (FoM) ranking; thus, they have radio and X-ray properties very similar to the EGRET blazars. Spectroscopic confirmation of these candidates is in(More)
We have previously reported on depth of interaction (DOI) positioning performance of 2×2 discrete LYSO crystal arrays coupled to digital silicon photomultiplier arrays (PDPC arrays). By optimizing the design of the interface between each neighboring crystal, DOI can be estimated from the overall light distribution collected by the 2×2 array of(More)
Supplementing existing survey data with VLA observations, we have extended γ−ray counterpart identifications down to decl. = -40 using our Figure of Merit approach. We find blazar counterparts for ∼ 70% of EGRET sources above decl. = -40 away from the Galaxy. Spectroscopic confirmation is in progress, and spectra for ∼ two dozen sources are presented here.(More)
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