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oai:www.ideals.illinois.edu:2142/80854 2023-07-11 col_2142_5131 col_2142_8888 com_2142_5130 com_2142_8887 com_2142_234

William D. O'Brien, Jr Bigelow, Timothy Allen 2015-09-25T20:08:30Z 2015-09-25T20:08:30Z 10000-01-01 2004 2004 This thesis considered the estimation of the in vivo power spectrum from the backscattered waveforms by finding the total attenuation along the propagation path. The total attenuation was estimated by assuming model for the scatterers (i.e., spherically symmetric Gaussian impedance distributions of unknown size) and then solving for the size and total attenuation simultaneously from the frequency dependence of the backscattered spectrum. The attenuation and scatterer size could be accurately and precisely estimated provided that sufficient frequency data was available. The accuracy and precision were significantly improved by increasing the range of frequencies used in the estimate. In addition, some improvement could be obtained by increasing the length of the window used to gate the backscattered RF echoes (i.e., samples in frequency domain independent). Although only applied to the estimation of scatterer size in this thesis, the estimation of the in vivo power spectrum using the developed methods could be applied to other tissue characterization procedures as well as estimating the temperature increase in the tissue from ultrasound exposures. Made available in DSpace on 2015-09-25T20:08:30Z (GMT). No. of bitstreams: 2 license.txt: 4848 bytes, checksum: 96035ab3f5e1c23cc7138a224ce498bd (MD5) 3130881.pdf: 7580236 bytes, checksum: 98f8deb50aeb0f0698ebf4b706823756 (MD5) Previous issue date: 2004 Embargo set by: Seth Robbins for item 82136 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 243 p. Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2004. http://hdl.handle.net/2142/80854 (MiAaPQ)AAI3130881 eng Health Sciences, Radiology Estimating the Medical Ultrasound in Vivo Power Spectrum text Electrical Engineering Electrical Engineering University of Illinois at Urbana-Champaign Dissertation Ph.D.