A spectroscopic Compton scattering reconstruction algorithm for 2D cross-sectional view of breast CT geometry

dc.contributor.authorChighvinadze, Tamar
dc.contributor.examiningcommitteeElbakri, Idris (Physics and Astronomy) Fiege, Jason (Physics and Astronomy) LoVetri, Joe (Electrical and Computer Engineering)en_US
dc.contributor.supervisorPistorius, Stephen (Physics and Astronomy)en_US
dc.date.accessioned2014-08-22T00:05:40Z
dc.date.available2014-08-22T00:05:40Z
dc.date.issued2014en_US
dc.degree.disciplinePhysics and Astronomyen_US
dc.degree.levelMaster of Science (M.Sc.)en_US
dc.description.abstractX-ray imaging exams are widely used procedures in medical diagnosis. Whenever an x-ray imaging procedure is performed, it is accompanied by scattered radiation. Scatter is a significant contributor to the degradation of image quality in breast CT. This work uses our understanding of the physics of Compton scattering to overcome the reduction in image quality that typically results from scattered radiation. By measuring the energy of the scattered photons at various locations about the object, an electron density (ρe) image of the object can be obtained. This work investigates a system modeled using a 2D cross-sectional view of a breast CT geometry. The ρe images can be obtained using filtered backprojection over isogonic curves. If the detector has ideal energy and spatial resolution, a single projection will enable a high quality image to be reconstructed. However, these ideal characteristics cannot be achieved in practice and as the detector size and energy resolution diverge from the ideal, the image quality degrades. To compensate for the realistic detector specifications a multi-projection Compton scatter tomography (MPCST) approach was introduced. In this approach an x-ray source and an array of energy sensitive photon counting detectors located just outside the edge of the incident fan-beam, rotate around the object while acquiring scattering data. The ρe image quality is affected by the size of the detector, the energy resolution of the detector and the number of projections. These parameters, their tradeoffs and the methods for the image quality improvement were investigated. The work has shown that increasing the energy and spatial resolution of the detector improves the spatial resolution of the reconstructed ρe image. These changes in the size and energy resolution result in an increase in the noise. Thus optimizing the image quality becomes a tradeoff between blurring and noise. We established that a suitable balance is achieved with a 500 eV energy resolution and 2×2 mm2 detector. We have also established that using a multi-projection approach can offset the increase in the noise.en_US
dc.description.noteOctober 2014en_US
dc.identifier.citationT. Chighvinadze and S. Pistorius, The Effect of Detector Size and Energy Resolution on Image Quality in Multi-Projection Compton Scatter Tomography. J Xray Sci Technol, 2014. 22: p. 113-128.en_US
dc.identifier.urihttp://hdl.handle.net/1993/23846
dc.language.isoengen_US
dc.publisherJournal of X-Ray Science and Technology, IOS pressen_US
dc.rightsopen accessen_US
dc.subjectScatter imagingen_US
dc.subjectElectron densityen_US
dc.subjectX-raysen_US
dc.titleA spectroscopic Compton scattering reconstruction algorithm for 2D cross-sectional view of breast CT geometryen_US
dc.typemaster thesisen_US
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