Development of a Miniature Real-Time High-Resolution Endoscopic 3D Ultrasound System

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The proposed research program is focused on developing high-frequency ultrasound technologies for use in high-resolution imaging applications. High-frequency ultrasound is a relatively new technology that uses micro-fabricated imaging probes that are capable of an order of magnitude higher resolution than conventional ultrasound systems currently used in diagnostic imaging. Specifically, the primary objective is to develop miniaturized (<3mm) imaging endoscopes and all of the associated electronic hardware and software that will enable this technology to be used as a tool for visualizing tissues from within the body, as opposed to the current equivalent technology that is limited to external topical applications. Potential applications of such a high resolution endoscope include laparoscopic, auditory, intracardiac, neural imaging, and many more. In conventional pulse-echo ultrasound, the resolution of the imaging system is proportional to the frequency of the ultrasound pulse generated by the transducer, however, higher frequency (higher resolution) comes at the price of lower penetration depth. Conventional low frequency large penetration ultrasound imaging systems are based on piezoelectric transducer arrays. By using a transducer array, which is made of many individually addressed piezoelectric elements, the effective curvature of the aperture can be changed electronically, resulting in a much better image quality. Use of an array also makes it possible to either multiplex a subset of elements across a much larger set of elements (linear array), or to steer the ultrasound beam to different angles from a fixed set of elements (phased array). Because phased arrays have the ability to steer the focused ultrasound beam, they can generate images with a large field-of-view from a much smaller form factor, and this makes them desirable for endoscopic applications as long as the diameter of the probe is not dominated by packaging of the electrical interconnects. This on-going research program has recently solved some of the challenges associated with developing miniature high frequency phased array endoscopes. These challenges include the micro-fabrication of the array elements and interconnecting these to a cabling system in a miniaturized form factor. Although the previously developed endoscope currently represents one of the most advanced ultrasound imaging arrays in the world, there are still a large number of research questions and challenges that need to be addressed before it can be realized as a useful diagnostic technology. The proposed research program will build upon these previous developments by designing, fabricating, and implementing first of a kind electronic hardware and software to allow the imaging endoscope to generate real-time high resolution images. The research program will also develop novel 2D micro-fabricated imaging arrays that will not only produce images of superior quality, but also real-time 3D volumes from an endoscope of identical miniaturized form factor. Currently no other imaging technology exists that combines such high resolution, with the miniature forward looking endoscopic form factor. The potential for this technology to revolutionize diagnostics in several different fields of medicine is very real. Not only could this be of great benefit to the Canadian health care system (and international) in terms of improving diagnostics and surgical guidance, but the technology also represents valuable IP that has many commercialization opportunities on both a local and national scale. This research program is also a very valuable training program for graduate students through a unique combination of high tech micro-fabrication training with conventional biomedical engineering methods.