基于压电单晶的前视型自旋转血管内超声探头基础研究

IntraVascularUltraSound (IVUS)is a medical imaging methodology using a specially designed catheter with a miniaturized ultrasound probe attached to the distal end of the catheter. It allows the application of ultrasound technology to see from inside blood vessels through the surrounding blood column, visualizing the endothelium (inner wall) of blood vessels in living individuals. It is thus showing increasing significance in early detection of atherosclerosis and coronary artery interventional diagnosis. Researchers and scientist are all aiming to achieve more sensitive, wider bandwidth, and more reliable IVUS probes in this field. Currently, the 360 degree side-looking scanning probe cannot meet the clinic requirements of Chronic Total Occlusion. Furthermore, as the commercial mechanical IVUS scanner is driven by an external motor through a long and soft shaft, imaging distortion is occurred when the probe head is scanning through narrow and curved blood vessels. In this project, we put forward innovatively a new model of intravascular ultrasonic imaging probe. It is based on a micro-sized permanent magnetic AC motor mounted in the probe head. A forward looking ultrasound transducer with a piezoelectric single crystal as active layer with driven directly by the micro motor. The probe head is miniaturized so that the external dimension is within 2 mm to meet intravascular requirements. We plan to study therelevant theory and technology of the integrated probe, covering micro-sized AC motor control, precise servo-controlledself-rotating system, the high frequency electromechanical coupling properties of ultra-thin piezoelectric unit, acoustic matching, image performances and frame rate stability, and so on. This proposed project will provide useful contributions to the technological development of high performance intravascular ultrasound probes with our own intellectual properties.

工作于狭窄冠动脉中的血管内超声探头，因可实时准确地描述血管壁三维解剖结构，在冠动脉粥样硬化早期检测及介入诊疗中意义重大。高灵敏度、宽频带、可靠性更优的探头是血管内超声研究者不断追求的目标。现有商品化的血管内超声探头均采用侧向360度扫查，无法满足完全性闭塞介入手术的临床需求，且机械旋转式探头是通过外置的马达带动软轴，易造成图像扭曲。针对上述问题，项目设计并研究一种外径为1.5至2 mm的超高频前视型自旋转血管内超声探头模型，并将最优压电性能的单晶超薄层运用于探头结构中，从超微型永磁电机的转动控制理论及实现、自旋转扫描精确伺服控制、超高频单晶换能器的机电耦合性能、声耦合、成像质量、图像帧频稳定性等几个层面进行理论建构、技术探索和性能表征，为实现我国自主知识产权的高性能血管内超声探头的理论及设计制造提供有益补充和创新发展。

工作于狭窄冠动脉中的血管内超声探头，因可实时准确地描述血管壁三维解剖结构，在冠动脉粥样硬化早期检测及介入诊疗中意义重大。高灵敏度、宽频带、可靠性更优的探头是血管内超声研究者不断追求的目标。然而现有商品化的血管内超声探头均采用侧向360度扫查，无法满足完全性闭塞介入手术的临床需求，且机械旋转式探头是通过外置的马达带动软轴，易造成图像扭曲。.本项目开展了基于压电单晶复合材料的前视型自旋转血管内超声探头研究。具体包括：.1）研制1.2 mm×3.7 mm低成本量产微型马达，最大转速275RPS，可避免马达外置成像导管的固有弊端。.2）实现单晶复合材料高频探头（0.5 mm×0.5 mm），中心频率 32.8 MHz，-6 dB 带宽为 73 %，插入损耗为-14 dB，表现出非常高的灵敏度。并将高频探头和微型马达植入外径2.0mm导管中，利用离子液体实现电气导通和声学耦合。.3）设计开发了血管内成像专用的成像平台和软件，进行了血管壁前视锥面扫描成像研究。.4）研制外径小于 9.5 mm 具备自动对焦功能的消化道超声内窥镜，高清广角（500~800 万像素）光学微型摄像模组，独特设计三轴自动对焦马达动态调整镜头角度，可确保探头在整个移动过程中光学视野都保持清晰。.本项目的研究内容得到了业内专家的认可，已在国际知名期刊发表SCI论文5篇，EI论文4篇，申请专利5项，授权专利5项，研究成果荣获第十八届中国国际高新技术成果交易会优秀产品奖。本项目的研究成果为血管内成像技术提供新手段，为相关仪器的国产化奠定了坚实的基础。