基于声异常透射效应的高强度聚焦超声换能器
HIFU Tranmitter Based on Extraordinary Acoustic Tran smission

高强度聚焦超声（High intensity focused ultrasound，HIFU）作为一种新型创的外科技术已在临床上应用于各种良恶性实体肿瘤治疗。为了实现安全高效的肿瘤治疗，HIFU换能器的聚焦效率仍然有待提高。本文综述了声异常透射效应的基本原理，以及近期利用声异常透射效应的HIFU聚焦超声换能器的研究。主要涉及两个方面的工作：（1）将声人工结构引入凹面型声透镜的设计，设计并制作了声超常透镜，对声透镜式聚焦换能器进行改进，达到了降低旁瓣的效果，从而提高了HIFU治疗的安全性；（2）基于球弧周期槽阵列设计并制作了超构聚焦换能器，以增强HIFU换能器聚焦效率。从理论及实验两方面研究了超构聚焦换能器与传统凹面换能器的声压分布和在组织中产生的温升。本文研究结果可进一步促进HIFU在临床治疗的广泛应用。
As an emerging non-invasive surgical technique,high intensity focused ultrasound (HIFU) has been used clinically in the treatment of various benign and malignant sol id tumors.The focusing efficiency of HIFU transducer still need to be improved to achieve safer and more effective tumor treatment.This paper reviews the principle of the extraordinary acoustic transmission,as well as the recent research on HIFU transducers that utilizing extraordinary acoustic transmission.Two aspects of work are involved:(1) The artificially acoustic structure is introduced into the design of concave acoustic lens,and a corrugated lens is designed and manufactured to improve the acoustic lens of the lens-focused transducer,which has achieved the effect of reducing side lobe and improved the safety of HIFU treatment;(2) Based on spherically periodic slot array,a metamaterial focusing transducer is designed and manufactured to enhance the focusing efficiency of the HIFU transducer.Enhanced acoustic focusing is demonstrated by both measuring and simulating sound pressure distribution of metamaterial focusing transducer and traditional concave transducer,as well as temperature elevation generated in the tissue.The results of this paper can further promote the wide application of HIFU in clinical treatment.