In vivo demonstration of noninvasive thermal surgery of the liver and kidney using an ultrasonic phased array

A 256-element, continuous-wave ultrasonic phased array has been used to the rmally coagulate deep-seated liver and kidney tissue. The array elements we re formed on a 1-3 piezocomposite bowl with a 10-cm radius of curvature and 12-cm diameter. The 0.65 x 0.65 cm(2) projection elements were driven at 1 .1 MHz by a custom-built amplifier system. A series of in vivo porcine expe riments demonstrated the ability to coagulate liver and kidney tissue using the large-scale phased array. The temperature response of the treatment wa s guided and monitored using magnetic resonance (MR) images, Focal lesion v olumes greater than 0.5 cm(3) in kidney and 2 cm(3) in liver were formed fr om a single 20-s sonication, (C) 1999 World Federation for Ultrasound in Me dicine & Biology.