A sparse-element phased array system based on sequentially multiple focusing for the treatment of large tumors

Abstract

The purpose of this study is the optimal design on High Intensity Focused Ultrasound transducer architecture with sparse-element to reduce the number of RF driving channels required for practical implementation for cost- and time-effective HIFU treatment of tumors. For rapid treatment of large-sized tumor while protecting healthy tissues, volumetric ablation by multiple focusing is one of the promising solutions, which does not require mechanical or electrical beam steering to move focus within a focal area. In the previous study, a numerical optimization with a 1017-element spherical-section ultrasound phased array transducer operating at a frequency of 1.0MHz with 16 cm radius of curvature was performed for the generation of multiple foci. The ultimate design of the current study is the sparse array so as to reduce the number of driving channels and cut down the cost. It is necessary that this design with less number of elements and driving channels shows similar sonication effect with the full array. The distribution of the reduced number of elements in the sparse array can be optimized by the incorporation of genetic algorithms to achieve acceptable properties for the radiation pattern. The simulation results of the optimized sparse array showed that the suggested distributional pattern of phased array achieved a well-defined focal zone with multiple foci at the aimed area. In conclusion, a sparse array can benefit from the reduction of the number of driving channels to achieve similar sonication effect with the full array.