基于三排混频超声换能器的超声图像引导辐射力操控方法研究

Currently, the major treating methods for malignant tumors are radiation treatment and chemo-treatment. It should be noted that there are huge side effects to the healthy cells in the human body during the treating process. If there is a way to deliver the drugs to where the disease locates, the regional drug concentration could be greatly enhanced and the side effects could be greatly eliminated. The ultrasound waves can be used for both imaging and acoustic manipulation. Small objects such as particles or microbubbles can be manipulated and moved using the acoustic radiation force effect, and this kind of particle transportation can be guided by ultrasonic imaging at the same time. In this sense, ultrasound is a good tool for localized drug delivery. In this project, we will develop a new type of transducer for “imaging” and “manipulation” at the same time. This transducer is composed of three linear arrays, whilst the middle row has higher frequency and is designed for imaging, and the outer two rows have lower frequency and are designed for acoustic radiation force manipulation. Based on the understanding of the manipulating mechanism and the optimum parameters for ultrasound, we will achieved efficient particle aggregating, manipulating and transporting in a high-speed flow environment. Our research can be detailed as following. 1) The new tri-row ultrasonic transducer will be designed and manufactured for both imaging and manipulating purposes. 2) A multi-channel ultrasonic electronic control system will be developed for both high-power acoustic radiation force generation and acute imaging. Using this system, precise timing control, channel selection, and beam synthesis can be performed for each single piezo-electric element. 3) In the non-flowing environment, the experiments of particle manipulation and transportation using acoustic radiation force will be performed. How do the ultrasound parameters and particle properties influence the manipulating effects will be detailed researched. 4）Elastic vascular phantoms will be made and a flow circulation circuit will be established. In the high-speed flowing environment, the experiments of particle manipulation and transportation using acoustic radiation force will be performed as well. It can be anticipated that the accomplishment of this project can provide new diagnostic method for malignant tumors.

目前恶性肿瘤治疗主要依靠放疗化疗，治疗的同时对健康细胞副作用很大。将药物定点输运到病灶可提高局部药物浓度并减少副作用。超声波具备成像和声操控双重功能，可实现超声图像引导下基于声辐射力效应的微小物体操控和移动，是理想的输运工具。本项目研究基于新型三排混频超声换能器的图像引导声辐射力粒子操控与输运方法，在理解声辐射力粒子操控的机制和确定最优化超声参数的基础上，实现血流状态下对粒子的精确聚集、搬运和定点释放。具体包括：1）研制兼具“成像”和“辐射力产生”功能的新型三排混频超声换能器；2）开发多通道大功率发射与敏锐成像的超声电子控制系统，实现每个阵元的精确延迟控制、通道选择、波束合成等；3）开展非流动状态下超声辐射力操控和定点搬运微小粒子的实验，评估超声参数和粒子特性对声操控的影响；4）制备血管仿体并构建流体循环系统，研究流动状态下的声辐射力操控和搬运效果。本项目的成功实施将为肿瘤治疗提供新思路。

传统放疗化疗在治疗恶性肿瘤的同时对病人健康组织有较大的副作用和创伤，药物输运技术可以将药物定点输运到病灶部位，增加局部药物浓度，极大减少对健康组织的副作用。超声场可以对流场中的粒子进行操控，而且可以对药物输运的过程进行实时成像和监控。由于超声波在医学临床的广泛应用，超声药物输运具有较好的应用平台和市场。为了实现超声药物定点输运技术，本项目研发了成像-操控多功能新型三排混频超声换能器、理论和实验研究了声场中颗粒受力及聚集效应、并通过离体和在体实验研究初步验证了利用新型超声换能器操控载药微泡和实时成像的可行性。本项目自实行以来，在IEEE TRANSACTIONS ON MEDICAL IMAGING、IEEE TRANSACTIONS ON NEURAL SYSTEMS AND REHABILITATION ENGINEERING、ACS Appl. Mater. Interfaces、Theranostics、Lamuir、Journal of Applied Physics、声学技术等期刊，发表论文9篇，其中SCI论文7篇，申请发明专利5项。