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oai:www.ideals.illinois.edu:2142/81141 2023-07-11 col_2142_5131 col_2142_8888 com_2142_5130 com_2142_8887 com_2142_234

Engineering, Electronics and Electrical New Developments on Quantitative Imaging Using Ultrasonic Waves text Oelze, Michael L. Lavarello Montero, Roberto Janniel 2015-09-25T20:09:44Z 2015-09-25T20:09:44Z 10000-01-01 2009 2009 Although ultrasound imaging is widely used for medical applications, conventional sonographic B-mode images are qualitative. As a consequence, medical diagnosis using sonograms is commonly subjective and depends on the expertise of the operator. The need to obtain quantitative information from tissues resulted in the development of alternative ways of processing the radiofrequency ultrasonic data. Two notable approaches are acoustic tomography and backscatter coefficient analysis. However, these techniques suffer from limitations that keep them from becoming widely used clinical tools. This dissertation presents several developments relevant to quantitative ultrasonic imaging using both acoustic tomography and backscatter coefficient analysis. First, a regularization method was developed to improve on the computational stability of acoustic tomography. The use of multiple frequency information to extend the region of convergence of acoustic tomography was validated experimentally. Second, the feasibility of obtaining quantitative density information (which is usually neglected in acoustic tomography) was explored. The practical limitations and convergence of existing density imaging approaches were studied, and improved algorithmic variations were developed and characterized. Third, two approaches for three-dimensional acoustic tomography were studied through simulations with emphasis on the effect of sensor topologies on the quality of the reconstructions. Finally, potential benefits of using an acoustic tomography scanner in conjunction with backscatter coefficient analysis were explored through simulations and experiments by performing full angular compounding and using acoustic tomograms for refraction correction. Made available in DSpace on 2015-09-25T20:09:44Z (GMT). No. of bitstreams: 2 license.txt: 4848 bytes, checksum: 96035ab3f5e1c23cc7138a224ce498bd (MD5) 3392112.pdf: 8950172 bytes, checksum: 70e3bd9eb20ff70f54d001408d49e320 (MD5) Previous issue date: 2009 Embargo set by: Seth Robbins for item 82423 Lift date: Forever Reason: Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs U of I Only 192 p. Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2009. http://hdl.handle.net/2142/81141 (MiAaPQ)AAI3392112 eng Electrical and Computer Engineering Electrical and Computer Engineering University of Illinois at Urbana-Champaign Dissertation Ph.D.