Ultrasound imaging arrays with improved transmit power capability

Abstract

Arrays optimized for conventional B-mode imaging applications are often limited in their ability to transmit power into the body, not by acoustic intensity limits but by face temperature maximums. Furthermore, new imaging modalities that use a long train of transmit pulses to remotely deposit a localized force on tissue are even more limited by array thermal considerations. Losses within the piezoceramic material are an important source of heat generation. Simply replacing the piezo material by one with lower losses will result in poorer imaging performance due to the physical properties and coarser microstructure of most low loss materials. This work describes the use of low loss piezoceramics exhibiting a microstructure that is ideal for forming into fine scale ultrasound arrays. Incorporating this material into multilayer ceramic and composite structures is shown to be an effective way to ameliorate the limitations of the base piezo and result in arrays with acoustic tank and imaging performance that is as good as or better than conventional imaging arrays made using a single layer of a conventional piezo. These arrays are also shown to exhibit reduced heating under equivalent electrical input power.