نتایج جستجو برای: beam ct

تعداد نتایج: 242842  

2008

Method Forty-three patients, among them 33 with known mitral regurgitation, underwent electron beam CT and MR imaging. Total left ventricular stroke volume (TSV), antegrade stroke volume (ASV), and mitral regurgitation volume (MRV) and fraction (MRF) were determined and compared between the two modalities. Additionaly electron beam CT measurements were compared with the corresponding echocardio...

2016
Sucheta Mohapatra Joseph M. Reinhardt John E. Bayouth Susan Walsh Christine Mundt Sabita Mohapatra Kailash Chandra Mohapatra

Recommended Citation Mohapatra, Sucheta. "Development and quantitative assessment of a beam hardening correction model for preclinical micro-CT." MS his contributions of time, ideas, and funding to make my graduate study experience so productive and stimulating. accomplishments shall continue to inspire me towards my future goals. I owe a lot to all my friends and colleagues in Iowa City, who h...

2017
Jasmine A. Oliver Patrick Kelly Sanford L. Meeks Twyla R. Willoughby Amish P. Shah

Purpose To characterize the accuracy of noncoplanar image guided radiation therapy with the Varian Edge radiosurgery system for intracranial stereotactic radiosurgery (SRS) treatments by assessing the accuracy of kV/kV orthogonal pair registration with Optical Surface Monitoring System (OSMS) monitoring relative to cone beam computed tomography (CT). Methods and materials A Computerized Imagi...

Journal: :Philosophical transactions. Series A, Mathematical, physical, and engineering sciences 2015
Hyoung Suk Park Yong Eun Chung Jin Keun Seo

This paper presents a mathematical characterization and analysis of beam-hardening artefacts in X-ray computed tomography (CT). In the field of dental and medical radiography, metal artefact reduction in CT is becoming increasingly important as artificial prostheses and metallic implants become more widespread in ageing populations. Metal artefacts are mainly caused by the beam-hardening of pol...

Journal: :CoRR 2017
Xuehang Zheng Il Yong Chun Zhipeng Li Yong Long Jeffrey A. Fessler

A major challenge in X-ray computed tomography (CT) is reducing radiation dose while maintaining high quality of reconstructed images. To reduce the radiation dose, one can reduce the number of projection views (sparse-view CT); however, it becomes difficult to achieve high quality image reconstruction as the number of projection views decreases. Researchers have applied the concept of learning...

2015
Kevin K. Grantham Hua Li Tianyu Zhao Eric E. Klein

The purpose of this study was to investigate the impact of tube potential (kVp) on the CT number (HU) to proton stopping power ratio (PSPR) conversion. The range and dosimetric change introduced by a mismatch in kVp used for the CT scan and the HU to PSPR table, based on a specific kVp, used to calculate dose are analyzed. Three HU to PSPR curves, corresponding to three kVp settings on the CT s...

Journal: :Clinical radiology 2007
J Gormally D A T Gay N E Manghat M P Williams

Since the introduction of the original singlesection computed tomography (CT) machines, and more recent spiral CT, several different types of CT artefact have been described. Recognized artefacts include motion artefact, metallic streak artefact, beam hardening, partial volume artefact and step artefact. The use of contrast-enhanced spiral CT has created many new artefacts and potential pitfall...

Journal: :Medical physics 2002
Ge Wang Shiying Zhao Dominic Heuscher

With the introduction of spiral/helical multislice CT, medical x-ray CT began a transition into cone-beam geometry. The higher speed, thinner slice, and wider coverage with multislice/cone-beam CT indicate a great potential for dynamic volumetric imaging, with cardiac CT studies being the primary example. Existing ECG-gated cardiac CT algorithms have achieved encouraging results, but they do no...

2014
Mercedes Martinson Nazanin Samadi George Belev Bassey Bassey Rob Lewis Gurpreet Aulakh Dean Chapman

The Biomedical Imaging and Therapy (BMIT) beamline at the Canadian Light Source has produced some excellent biological imaging data. However, the disadvantage of a small vertical beam limits its usability in some applications. Micro-computed tomography (micro-CT) imaging requires multiple scans to produce a full projection, and certain dynamic imaging experiments are not possible. A larger vert...

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