Ultrasound therapy system and ablation results utilizing miniature imaging/therapy arrays

Array-based imaging and therapy systems have several advantages over single element approaches, and it was previously shown that the imaging and therapy functionality may be combined into dual-mode arrays. In this work, minimally invasive, miniature (2.2 mm /spl times/ 50 mm aperture, 3.3 mm diameter) dual-mode linear arrays have been developed into probes with high acoustic power output (100 W, and >120 W/cm/sup 2/ at the source), high transmit efficiency (>65% typical), and good imaging performance (3.4 MHz center frequency, 50% fractional bandwidth, >100 mm deep field of view). These therapy / imaging probes have been integrated into a flexible intense ultrasound surgery platform which also includes conventional diagnostic imaging probes. A system architecture has been developed which includes a 64-channel therapy driver with software selection of array aperture and phasing (1/16th wavelength), frequency (0.5-8 MHz), drive amplitude (5 W/channel, nominal), mechanical rotational steering (/spl plusmn/180 degrees), and temporal sequencing/switching of imaging, and therapy modes. The array-based imaging/therapy system has produced encouraging results in preclinical studies of bulk tissue ablation, imaging and treatment monitoring of liver in vitro and in vivo, examples of which are presented. The system can be applied to ablation of other soft tissue pathologies, e.g. kidney, heart, uterus, brain, GI, etc.