P1B-10 Advantages of Capacitive Micromachined Ultrasonics Transducers (CMUTs) for High Intensity Focused Ultrasound (HIFU)

In the past ten years, high intensity focused ultrasound (HIFU) has become popular for minimally invasive and non-invasive therapies. Traditionally piezoelectric transducers have been used for HIFU applications, but capacitive micro- machined ultrasonic transducers (CMUTs) have been shown to have advantages, including ease of fabrication and efficient performance. In this paper, we show the fabrication and testing of CMUTs specifically designed for HIFU. We compare the operation of these designs with finite element models. In addition, we demonstrate that CMUTs can operate under high pressure and continuous wave (CW) conditions, with minimal self-heating, a problem that piezoelectric transducers often face. Finally, we demonstrate MR-temperature monitoring of the heating created by an unfocused HIFU CMUT.