Hybrid High Intensity Focused Ultrasound Transducer Development

描述（由申请人提供）：一种新型的HIFU（高强度聚焦超声）线性阵列换能器，能够同时作为治疗和成像探头，将在此项目中开发。成像和治疗的声学要求相互矛盾，导致不同的压电材料特性的每一种操作模式。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解耦，但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，以及用于图像接收的单独的整体PVDF共聚物换能器。变送器利用压电陶瓷材料优越的机电耦合系数，提高效率，减少大功率发电时的热问题。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)构建单元件混合换能器以产生高强度声场，同时作为高性能a模式换能器；2)设计有源箝位电路以产生用于脉冲回波接收的短成像脉冲；3)构建元素相控阵以测量用于治疗和成像的足够阵列性能。从长远来看，Spectrasonics将利用这种传感器设计开发和商业化超声引导HIFU治疗系统，用于心脏、血管和腹部器官（如肝脏、肾脏和胰腺）疾病的微创治疗。作为其最初的焦点，谱科选择了心脏消融治疗心房颤动。超声治疗是多年来研究的课题，但直到最近，这项技术才发现有效和广泛的医学应用。高强度聚焦超声（HIFU）是一种能够选择性破坏体内组织体积的非侵入性技术。HIFU旨在以可预测和可重复的方式在声束的焦点区域消融组织（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重大改进的潜力。

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.