2011 Joint AAPM/COMP Meeting
William O'Brien
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Our early work to develop a basis for quantitative ultrasound (QUS) imaging started with
live animal studies wherein the ultrasonic backscattered coefficient (BSC) was estimated
and from the BSC estimate, QUS parameters were estimated. Even earlier (some 5
decades earlier), significant through-transmission quantitative studies of ultrasonic tissue
properties were undertaken (absorption and speed). It was our view, based on the
significant early echo-based work by Lizzi et al., Zagzebski et al., Insana et al. and Hall
et al., that QUS imaging technology had the potential to be a new imaging capability that
could be used to augment standard B-mode imaging. QUS imaging utilizes the
frequency-dependent information, and thus the backscattered signals are dependent on
the tissue properties (size, shape, number, compressibility, density). Estimating QUS
parameters requires a model that incorporates a form factor (FF), that is, a mathematical
description/model of the backscattered signal of a single scattering structure as a function
of frequency; the better the FF describes anatomical scatterers, the more realistic will be
the estimates. We initiated our studies by examining in vivo three solid tumor types
(fibroadenoma, mammary carcinoma, soft-tissue sarcoma). Initially the Gaussian FF was
used. Good agreement between processed ultrasound data and pathologic assessments
were obtained, but also important questions were being raised. The questions lead to a
new approach to identify more accurate FFs as well as new strategies to extract
quantitative parameters from the envelop-detected echo data. The current QUS studies
are in collaboration with colleagues at the University of Wisconsin-Madison, Iowa State
University, University of Illinois at Chicago, Brown University and Riverside Research.
The presentation will provide the basis for QUS based on our early work as well as our
on-going work.

Research sponsored by NIH CA111289

Learning objectives:
1) Understand backscattered coefficient (BSC) QUS parameters and their relations to
tissue properties
2) Understand how to acquire QUS parameters from BSCs
3) Understand the basic concept of QUS and BSC analyses
4) Understand QUS parameters and their relations to tissue properties

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