Optimized 2D array design for Ultrasound imaging

Ultrasound imaging is one of the least expensive and safest diagnostic modalities routinely used. An attractive recent development in this field is three-dimensional (3D) imaging with two-dimensional (2D) matrix probes. The difficulty in implementing these probes comes from their large number of elements; for instance, the probe considered in this paper is composed of 1024 elements, whereas the number of channels of most current beamformers ranges from 64 to 256. To reduce the number of active elements, we propose a new sparse array design technique based on simulated annealing. Our method is capable of significantly reducing the number of probe elements as well as the side lobe level in a reasonable amount of computing time. Experiments in the context of hepatic biopsy show that good imaging performance can be obtained with only 177 active elements out of the total of 1024.