Ultrasound acoustic stimulated emission for controlling thermal surgery

Vibro-acoustography, a relatively new imaging modality, is applied to imaging ex vivo liver tissue from calves and New Zealand white rabbits. In the first series of experiments, calf liver tissue was heated while the USAE response and temperature were recorded. This demonstrated a strong temperature dependence of the USAE signal. In the second series of experiments lesions were created with focused ultrasound and then raster scanned in the focal plane by the two intersecting focused ultrasound fields. The FWHM of these USAE-amplitude scans correlates well with the lesion sizes measured in histological studies. This method successfully rendered high-resolution images of the necrosed lesions in the liver tissue. In addition, a correlation between the time after sonication and amplitude of the USAE response was observed.