Transducer assembly for generating focused ultrasound

An ultrasound transducer assembly for generating focused ultrasound, the ultrasound transducer assembly comprising:

• a composite piezoelectric layer;
• an acoustic lens having a proximal surface and a curved distal surface, wherein the proximal surface is attached to the composite piezoelectric layer, wherein the acoustic lens comprises 85% aluminum by weight;
• and
• a polymer acoustic impedance matching layer coating the curved distal surface of the acoustic lens, wherein the polymer acoustic impedance matching layer is formed from a p-xylylene based polymer;
• wherein an acoustic impedance of the composite piezoelectric layer matches an acoustic impedance of the acoustic lens within +−40%;
• and
• wherein the curved distal surface has an elliptical shape;
• and
• wherein the acoustic lens has an f-number of less than two.

An ultrasound system for generating focused ultrasound, the ultrasound system comprising:

• an ultrasound transducer assembly comprising:
• a piezoelectric layer;
• an acoustic lens having a proximal surface and a curved distal surface, wherein the proximal surface is attached to the piezoelectric layer;
• and
• an acoustic impedance matching layer coating the curved distal surface of the acoustic lens;
• driver circuitry operably connected with the ultrasound transducer assembly, wherein the driver circuitry is configured to deliver electrical pulses with a voltage and operating frequency sufficient for generating ultrasound pulses for performing histotripsy;
• wherein an acoustic impedance of the piezoelectric layer approximately matches an acoustic impedance of the acoustic lens;
• and
• wherein the acoustic impedance matching layer is a quarter wave matching layer.