We design, develop and evaluate micro-ultrasound devices and systems tailored for new imaging applications. Micro-ultrasound technology achieves better image resolution than standard clinical ultrasound because higher frequency transducers are used, corresponding to shorter wavelengths. The improved image resolution allows finer details of tissue structures to be visualised, such as the different layers of the skin or the internal structure of nerves.
The improved resolution comes at the cost of a shallower imaging depth, however, miniaturization is possible because the transducer dimensions scale with the wavelength. For example, a 192-element array operating at a typical clinical imaging frequency (5 MHz) is over 50 mm long, while a similarly designed probe at 50 MHz micro-ultrasound probe would be just over 5mm long, at 30 microns per element.
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We fabricate ultrasound transducers and arrays at our lab in order to create new ultrasound devices designed for specific applications. The feature sizes of micro-ultrasound transducers require micromachining tools for fabrication, such as dicing saws and laser machining systems also used in manufacturing electronics. We connect our fabricated devices to ultrasound systems that we program with the desired imaging sequences to evaluate the prototypes and novel imaging modes.
We are interested in miniaturised micro-ultrasound technologies to image where there is limited access, such as in the oral cavity, to determine the depth of invasion of oral cancers. We also develop and use micro-ultrasound for evaluating changes in tissues during disease progression and treatment, such as pre-clinical studies of breast cancers or stroke. We combine the high-resolution micro-ultrasound imaging with acoustic contrast agents or photoacoustic imaging to evaluate other characteristics of tissues such as vascularisation and perfusion. The creation of new transducer hardware is a key enabling technology for new ultrasound imaging modes and techniques. This in turn allow us and other researchers to better understand tissue characteristics and their changes with disease and treatment.