Experimental study of high intensity focused ultrasonic fields generated by piezocomposite transducers

摘要

In this paper, acoustic fields of HIFU transducers were studied experimentally. HIFU transducers based on focusing elements made from porous piezoelectric ceramics were fabricated and studied. The influence of HIFU transducers design features on acoustic fields generated in water were measured using 3D ultrasonic measurement systems UMS3 and calibrated hydrophones (Precision Acoustics Ltd.). Experimental results were compared with the FEM modeling of the forms of natural oscillations of the porous piezoelements on electric resonant and antiresonant frequencies. It was shown, that any kind of irregularities in the shape and size of focused piezoceramic element, working frequency, as well as transducers design peculiarities (housing, membrane etc.) strongly influence acoustic field distribution (acoustic pressure, side lobs level etc.). Ex vivo experiments on tissues and acoustic phantoms confirmed the results of measurements and calculations.