Thermoacoustic Tomography - Reconstruction of Data Measured under Clinical<br/><br/>Constraints

Wednesday, January 11, 2006 - 9:00am - 9:45am
EE/CS 3-176
Sarah Patch (University of Wisconsin)
Thermoacoustic tomography (TCT) is a hybrid imaging technique that has been
proposed as an alternative to xray mammography. Ideally, electromagnetic (EM)
energy is deposited into the breast tissue uniformly in space, but impulsively
in time. This heats the tissue causing thermal expansion. Cancerous masses
absorb more energy than healthy tissue, creating a pressure wave, which is
detected by standard ultrasound transducers placed on the surface of a
hemisphere surrounding the breast. Assuming constant sound speed and zero
attenuation, the data represent integrals of the tissue's EM absorptivity over
spheres centered about the receivers (ultrasound transducers).

The inversion problem for TCT is therefore to recover the EM absorptivity
from integrals over spheres centered on a hemisphere. We present an
inversion formula for the complete data case, where integrals are measured
for centers on the entire sphere. We discuss differences between ideal and
clinically measurable TCT data and options for accurately reconstructing the
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