Optimized backing design for a 3D transthoracic echocardiography (TTE) probe

An ASIC-integrated probe generates large amount of heat compared to that of a conventional probe. That causes to increase surface temperature and to degrade ultrasound diagnostic images in order not to exceed the temperature limits determined by the IEC standard 60601-2-37. In this paper, properties of backing material, inserted between transducer and ASICs, were studied for suppressing the probe surface temperature rise. The backing layer can work as a heat flow controller like an insulator or a conductor, depending on a cooling method. As a result of thermal simulation, it suggested that thermal resistance of the backing should be as high as possible in natural convection t o isolate heat-flow from ASICs to transducer, whereas it should be as low as possible in active cooling because the heat dissipation amount was high at a radiator and thus the heat generated by the transducers could be transferred away from the probe surface. In our experiment with two backings having different thermal conductivity, the maximum surface temperature rise was improved by 8.2 %. We believe that this design approach should enable a probe to achieve best performance.