HIFU has been widely used to treat different types of tumors, including those of prostate, liver, breast, kidney, bone and pancreas because of its non-invasive and precise approach for tissue ablation. For successful HIFU operation, it is important to have a reliable guidance and treatment monitoring method such as ultrasound imaging. Most of ultrasound imaging-guided HIFU system are not compact, because it requires a cooling system for the transducer, and needs separate imaging and HIFU transducers. This is due to the properties of piezoelectric transducers such as self-heating. On the other hand, Capacitive Micromachined Ultrasonic Transducers (CMUTs) have a distinctive advantage over piezoelectric transducers in respect to self-heating mechanism and wide fractional bandwidth.

In this talk, I will present a compact dual-mode ultrasound system that can perform ultrasound imaging and HIFU using 2-D CMUT array. The probe is equipped with a dual-mode application-specific integrated circuit(ASIC) and a 32 x 32-element 2-D CMUT array. Both dual-mode ASIC and CMUT array are integrated to the probe with a flexible printed circuit board using flip-chip bonding. Also, I will talk about the new CMUT array design that can produce higher output pressure without device failure. With new CMUT array, the focused pressure at F-1 (8mm) was measured to 16.33 MPa peak-to-peak. An ablation test was successfully performed both on HIFU phantom gel and ex-vivo tissue. Lastly, I will show the demonstration of ultrasound imaging guided HIFU on ex-vivo tissue using dual-mode ultrasound system.