A Scheme for Ultra-Fast Computed Tomography Based on Stationary Multi-Beam X-ray Sources

Gong, Hao

A Scheme for Ultra-Fast Computed Tomography Based on Stationary Multi-Beam X-ray Sources

dc.contributor.author	Gong, Hao	en
dc.contributor.committeechair	Cao, Guohua	en
dc.contributor.committeemember	Zhu, Yizheng	en
dc.contributor.committeemember	LaConte, Stephen M.	en
dc.contributor.committeemember	Wyatt, Chris L.	en
dc.contributor.committeemember	Wang, Ge	en
dc.contributor.department	Biomedical Engineering	en
dc.date.accessioned	2017-02-17T09:00:17Z	en
dc.date.available	2017-02-17T09:00:17Z	en
dc.date.issued	2017-02-16	en
dc.description.abstract	The current cardiac computed tomography (CT) technology is mainly limited by motion blurring and radiation dose. The conceptual multi-source interior CT scheme has provided a potential solution to reduce motion artifacts and radiation exposure. This dissertation work conducted multi-facet investigations on a novel multi-source interior CT architecture (G. Cao, et. al, IEEE Access, 2014;2:1263-71) which employs distributed stationary multi-beam Carbon-nanotube (CNT) X-ray sources and simultaneously operates multiple source-detector chains to improve temporal resolution. The collimation based interior CT is integrated in each imaging chain, to suppress radiation dose. The central thesis statement is: Compared to conventional CT design, this distributed source array based multi-source interior CT architecture shall provide ultra-fast CT scan of region-of-interest (ROI) inside body with comparable image quality at lower radiation dose. Comprehensive studies were conducted to separately investigate three critical aspects of multi-source interior CT: interior CT mode, X-ray scattering, and scatter correction methods. First, a single CNT X-ray source based interior micro-CT was constructed to serve as a down-scaled experimental verification platform for interior CT mode. Interior CT mode demonstrated comparable contrast-noise-ratio (CNR) and image structural similarity to the standard global CT mode, while inducing a significant radiation dose reduction (< 83.9%). Second, the data acquisition of multi-source interior CT was demonstrated at clinical geometry, via numerical simulation and physical experiments. The simultaneously operated source-detector chains induced significant X-ray forward / cross scattering and thus caused severe CNR reduction (< 68.5%) and CT number error (< 1122 HU). To address the scatter artifacts, a stationary beam-stopper-array (BSA) based and a source-trigger-sequence (STS) based scatter correction methods were proposed to enable the online scatter measurement / correction with further radiation dose reduction (< 50%). Moreover, a deterministic physics model was also developed to iteratively remove the scatter-artifacts in the multi-source interior CT, without the need for modifications in imaging hardware or protocols. The three proposed scatter correction methods improved CNR (< 94.0%) and suppressed CT number error (< 48 HU). With the dedicated scatter correction methods, the multi-source interior CT could provide ROI-oriented imaging with acceptable image quality at significantly reduced radiation dose.	en
dc.description.degree	Ph. D.	en
dc.format.medium	ETD	en
dc.identifier.other	vt_gsexam:9743	en
dc.identifier.uri	http://hdl.handle.net/10919/75054	en
dc.publisher	Virginia Tech	en
dc.rights	In Copyright	en
dc.rights.uri	http://rightsstatements.org/vocab/InC/1.0/	en
dc.subject	Multi-source	en
dc.subject	computed tomography	en
dc.subject	scatter correction	en
dc.subject	temporal resolution	en
dc.subject	interior tomography	en
dc.title	A Scheme for Ultra-Fast Computed Tomography Based on Stationary Multi-Beam X-ray Sources	en
dc.type	Dissertation	en
thesis.degree.discipline	Biomedical Engineering	en
thesis.degree.grantor	Virginia Polytechnic Institute and State University	en
thesis.degree.level	doctoral	en
thesis.degree.name	Ph. D.	en