title: Tests of backscatter coefficient measurement using broadband pulses.
abstract: An adaptation to a data reduction method is outlined for determining backscatter coefficients, eta, when broad-bandwidth pulses are employed. The accuracy of these eta values is assessed with well-characterized phantoms, for which backscatter coefficients based on their physical properties have been independently calculated. One phantom produces Rayleigh-like scattering, where the backscatter coefficient varies smoothly with frequency over the analysis bandwidth. A second phantom exhibits local maxima and minima in the scattering function versus frequency due to the presence of millimeter-sized graphite gel spheres in a gel background. The method was found to produce accurate results using time gate durations as small as 2 mus, although better accuracy is obtained for longer gate durations, particularly when the sample exhibits resonance peaks in backscatter versus frequency. Use of a Hamming window in place of a rectangular window extends the accuracy near the upper and lower limits of the frequency range.
authors.affiliation: Dept. of Med. Phys., Wisconsin Univ., Madison, WI.
authors.forename: J F
authors.initials: JF
authors.lastname: Chen
authors.forename: J A
authors.initials: JA
authors.lastname: Zagzebski
authors.forename: E L
authors.initials: EL
authors.lastname: Madsen