Hybrid High Intensity Focused Ultrasound Transducer Development

描述(申请人提供)：在该项目期间，将开发一种新型的HIFU(高强度聚焦超声)线阵换能器，它可以同时用作治疗和成像探头。对成像和治疗的相互矛盾的声学要求导致了每种操作模式的不同的压电材料特性。为了克服这一困难，提出了一种混合换能器设计，将传输操作与接收功能分离，同时保持共面成像和治疗。该换能器将结合使用用于治疗和脉冲产生的压电陶瓷和用于图像接收的单独的一体化PVDF共聚换能器。该变送器利用压电陶瓷材料优异的机电耦合系数来提高效率，减少高功率发电过程中的热问题。通过配置单独的PVDF接收器，可以在图像接收期间获得更高的灵敏度和带宽。该计划的目标是通过以下方式展示改进的两用换能器能力：1)构建单个元件混合换能器，以产生高强度声场，同时充当高性能的A型换能器；2)设计有源钳位电路，产生用于脉冲回波接收的短成像脉冲；3)构建基本相控阵，以测量足够的阵列治疗和成像性能。从长远来看，Spectrasonics将利用这种换能器设计开发超声引导的HIFU治疗系统，并将其商业化，用于心脏、血管和腹部器官疾病的微创治疗，如肝脏、肾脏和胰腺。对于最初的焦点，Spectrasonics选择了心脏消融治疗心房颤动。多年来，超声治疗一直是研究的主题，但直到最近，这项技术才发现了有效和广泛的医学应用。高强度聚焦超声(HIFU)是一种非侵入性技术，能够选择性地破坏体内的组织体积。HIFU旨在以可预测和可重复的方式消融声束焦点区域的组织(产生病变)。这项技术代表了图像引导的微创治疗的重大进步，并为各种软组织疾病的治疗提供了显著改进的潜力。

DESCRIPTION (provided by applicant): A new type of HIFU (High Intensity Focused Ultrasound) linear array transducer, which is able to simultaneously function as a therapy as well as imaging probe, will be developed during this program. Contradictory acoustic requirements for imaging and therapy result in disparate piezoelectric material characteristics for each mode of operation. To overcome this difficulty a hybrid transducer design is proposed that will decouple the transmission operation from the receive function yet maintain coplanar imaging and therapy. The transducer will combine the use of a piezoelectric ceramic for therapy and pulse generation with a separate integral PVDF copolymer transducer for image reception. The transmitter uses the superior electromechanical coupling coefficient of piezoceramic materials to improve efficiency and reduce thermal problems during high power generation. By configuring a separate PVDF receiver one is able to obtain greater sensitivity and bandwidth during image reception. The goal of this program is to demonstrate improved dual use transducer capability by: 1) Constructing a single element hybrid transducer to produce high intensity acoustic field while functioning as a high performance A mode transducer 2) Designing an active clamping circuit to produce short imaging pulses for pulse echo reception 3) Constructing an elemental phased array to measure adequate array performance for both therapy and imaging. In the longer term Spectrasonics will utilize this transducer design for the development and commercialization of ultrasonically guided HIFU therapy systems for the minimally- invasive treatment of diseases of the heart, vascular and abdominal organs such as the liver, kidney and pancreas. For its initial focus Spectrasonics has chosen cardiac ablation for the treatment of Atrial Fibrillation. Ultrasound therapy has been the subject of research for many years, but it is only recently that this technique has found effective and widespread medical applications. High Intensity Focused Ultrasound (HIFU) is a noninvasive technique capable of selective destruction of tissue volumes within the body. HIFU is designed to ablate tissue (produce lesions) in the focal region of an acoustic beam in a predictable and reproducible manner This technology represents a major advance in image guided, minimally invasive therapy, and offer the potential to provide significant improvements in the treatment for a wide variety of soft tissue diseases.