Phase aberration correction and motion compensation for ultrasonichyperthermia phased arrays: experimental results

摘要

In ultrasound hyperthermia, focal patterns generated by phasednarrays can be degraded by phase errors due to tissue inhomogeneities,ndigitization of the driving signals, and imperfect fabrication of thentransducers. The degree of degradation depends on the severity of phasenaberrations. As predicted by simulation and verified by experimentalnresults, focal degradation scales with the circular variance of phasenerrors. However, degraded power deposition patterns can be significantlynimproved after phase aberration correction, especially where patternsnare complicated and the aberrations are severe. Also, as shown in motionncompensation experiments, an aberration corrected pattern can benparticularly sensitive to aberrator movement greater than thencorrelation length of the aberrator. After motion compensation, newnsharply focused patterns can be accomplished, thus reducing the unwantedninfluence of “body” movement by stabilizing the positions ofnfoci with respect to patient anatomy