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Title:Analysis and Approximation of Pulse-Echo Ultrasound Backscattering Coefficients
Author(s):Ridgway, William
Contributor(s):Oelze, Michael
backscatter coefficient
backscatter coefficient estimation
Abstract:In previous methods for estimating backscatter coefficients from ultrasound measurements using focused transducers, a single reference pulse from the focus of the source was used to eliminate equipment characteristics. However, these methods assume that diffraction effects have minimal influence on the frequency dependence of the backscatter coefficient when estimating from regions outside the focus but within the depth of field of the transducer. It was hypothesized that more accurate backscatter coefficients from regions of interest (ROIs) throughout the depth of field of the transducer could be produced by using reference pulses at the same location as the ROI in the field. The multiple references should allow the diffraction effects to be better accounted for in the backscatter coefficient estimations. To test the hypothesis, reflected pulses from a phantom with well-defined scattering properties and a reference planar reflector were measured and analyzed. Backscatter coefficients were estimated from the same ROI inside the phantom; however, the distance of the ROI from the transducer was varied. Backscatter coefficients were calculated using reference pulses from the focus and compared to backscatter coefficients using references from the same location in the field as the ROI. Three different transducers with different focal properties were used in the study (F2 and center frequency of 8 MHz, F3 and center frequency of 9 MHz, and F4 and center frequency of 10 MHz). The mean squared error (MSE) was used to quantify the differences in backscatter coefficient calculations from different locations in the field using a single reference from the focus compared to using references at the same field location as the ROI. Results indicated that the new technique improved the backscatter coefficient estimates for locations in the field outside the focus for weakly focused sources.
Issue Date:2009-12
Publication Status:unpublished
Peer Reviewed:not peer reviewed
Date Available in IDEALS:2014-01-22

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