Compressibility and Density Weighting for Ultrasound Scattering Tomography

A novel reconstruction technique based on delay-and-sum ultrasound tomography algorithms is introduced. This reconstruction technique enables ultrasound tomographic systems to produce compressibility- and density-weighted images (D-WI) for spherically symmetric ultrasound scatterers. The efficacy of this reconstruction technique was demonstrated with simulation and phantom experiments. Separation between a dense wire target and a compressible thread target within a phantom was quantified, showing an increased signal of the wire target for D-WIs. The suppression of background scatter in D-WIs was also quantified. Resolution was calculated for these reconstruction techniques, exemplifying the half-wavelength diffraction-limited resolution capabilities of this ultrasound scattering tomography system. The proposed technique offers a 6.5× enhanced minimum-detectable density-contrast sensitivity compared to traditional B-scan imaging for a 100-μm target. This enhanced detectability is expected to prove advantageous for microcalcification imaging.