Small Aperture Ultrasound Transducers for Intracavitary Tissue Ablation
Catheter directed ultrasound (US) transducer is capable of delivering high, focused acoustic power to the target tissue inside a body. The direct interaction with the tissue enables to minimize the concern of unintended tissue damages. Despite the potential advantages, the current therapeutic application of the intracavitary US device and literature is due to the inefficient delivery of the acoustic power from the small aperture and difficulty in fabrication. Therefore, we aim to develop a miniaturized intracavitary US transducer for tissue ablation. The proposed device is composed of double-layered PZT-5A, a matching layer, and a backing layer. Relatively high acoustic pressure (4.7 MPa) was generated by the small aperture (2 mm) prototypes. The therapeutic efficacy of the proposed method was validated through ex-vivo tests using porcine kidneys. Upon the sonification, the tissue temperature elevated to over 43 °C within 20 sec and the maximum temperature reached up to 53 °C at the five-minute sonification. The lesion volume after the US treatment was about 6.8 mm3. The developed catheter US transducer can be used to ablate a tumor in deep organs of the body by guiding it through an endoscopic device.
