Strip-electrode ultrasonic arrays for production of asymmetric therapeutic thermal lesions

The authors are investigating high-intensity ultrasonic beams shaped to produce thermal lesions with asymmetric cross-sections. The desired lesions are broad in one cross-sectional dimension; this permits the therapy transducer to be scanned in the orthogonal direction in order to treat large tumor volumes with closely packed lesion matrices. The authors have conducted initial theoretical studies relevant to the formation of such lesions, and they have constructed suitable therapeutic arrays that employ spherical focussing with parallel strip electrodes. In-vitro studies in liver and the ocular lens have demonstrated that the desired lesion geometry can be achieved.