Ultrasonic arrays for ultrahigh resolution real time biomedical imaging

该项目涉及多学科合作，将材料研究、设备设计和医学导向测试相结合，以创建能够实时进行超高分辨率生物医学成像的超声波阵列。实时超声成像是一种安全、廉价、方便的技术，约占所有医院影像学检查的20%。然而，空间分辨率最终受到最大频率的限制，现有的超高分辨率系统基于机械扫描的单元件换能器。这种系统需要提高分辨率，但同时也限制了进度，因为它们不能实时使用。为此，需要能够在高于目前最大频率~ 30mhz的频率下工作的超声波阵列。然而，到目前为止还不可能生产出这样的阵列。压电复合材料由聚合物基质中的陶瓷柱组成，是目前商用超声成像系统中最先进的材料，具有更高的机电耦合，更好的声阻抗与生物组织匹配，以及比单独的压电陶瓷更好的电性能，从而导致更宽的固有带宽和更高的灵敏度。此外，减少横向耦合意味着可以从单片压电复合材料板定义多元素阵列。然而，制造微米尺度材料的困难阻碍了高频超声换能器和阵列的采用。在提出的研究计划中，超声波阵列将首次被创造出来，其工作频率可能高达100兆赫兹，适合于超高分辨率的实时成像。这一进步的关键将是我们将利用优化的净形状陶瓷加工技术，结合最先进的复合材料设计，生产超细尺度的压电复合材料。这将是实现实时生物医学超声成像的重要一步，目前不可能实现的频率，最终允许对皮肤病学、眼科、小部位癌症、牙科和心血管系统等领域的一系列医疗状况进行新的理解和更好的诊断，有时在腔内配置。

The project involves collaborative, multidisciplinary work combining materials research, device design, and medically-oriented testing to create ultrasonic arrays capable of ultrahigh resolution biomedical imaging in real time. Real-time ultrasonic imaging is a safe, inexpensive and convenient technique which accounts for approximately 20% of all hospital imaging examinations. However, spatial resolution is ultimately limited by maximum frequency and existing ultrahigh resolution systems are based on mechanically-scanned single-element transducers. Such systems demonstrate the need for increased resolution but at the same time limit progress because they cannot be used in real time. For this, ultrasonic arrays are needed which can operate at frequencies higher than the present maximum of ~30 MHz. However, it has so far been impossible to produce such arrays.Piezocomposite materials, comprising ceramic pillars in a polymer matrix, are now state-of-the-art in commercial ultrasonic imaging systems, with higher electromechanical coupling, better acoustic impedance matching to biological tissue, and better electrical properties than piezoceramics alone, leading in turn to wider intrinsic bandwidth and higher sensitivity. In addition, reduced lateral coupling means that multi-element arrays can be defined from monolithic piezocomposite plates. However, difficulties manufacturing material with micron-scale dimensions has blocked adoption in high frequency ultrasonic transducers and arrays. In the research programme being proposed, ultrasonic arrays will be created to operate for the first time at frequencies potentially as high as 100 MHz, suitable for ultrahigh resolution imaging in real time. The key to this advance will be the ultrafine scale piezocomposites we will produce with optimised net shape ceramic processing technology, in combination with state-of-the-art composite design. This will be a major step forward in enabling real time biomedical ultrasonic imaging at presently impossible frequencies, ultimately allowing new understanding and better diagnosis of a range of medical conditions in areas such as dermatology, ophthalmology, small parts cancers, dentistry, and the cardiovascular system, sometimes in intralumenal configurations.