Ultrasonic arrays for ultrahigh resolution real time biomedical imaging

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.