Optical ultrasound probes to provide detailed imaging and guide surgical tools

1 min read

Minimally invasive surgical procedures could be guided more precisely and efficiently, using a new real-time imaging technique known as optical ultrasound.

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The optical ultrasound probes are being developed by Dr Adrien Desjardins at University College London, who was recently announced as one of the first nine recipients of the EPSRC Healthcare Technologies Challenge Awards.

The awards, designed to encourage research that will improve healthcare diagnosis and treatment, will allow the successful researchers to work with clinicians, companies and charities to help speed up the clinical adoption of their technologies.

The nine researchers, each of whom will receive a share of a £9m fund, are developing technologies ranging from smart wound dressings and new ways to examine sperm, to tools to improve diagnosis and cancer treatment.

The new optical ultrasound probes are designed to be integrated into devices such as needles and catheters, to provide detailed imaging from inside the body and help guide the surgical tools, according to Desjardins.

“Ultrasound imaging can provide exquisite visualization of tissue from within the body to guide minimally invasive medical procedures,” he said. “Currently, though, ultrasound imaging is performed with electronic transducers, which have costs that are often prohibitive for single-use medical devices, and they are too bulky for many procedures.”

The new imaging probes, in contrast, generate and receive ultrasound waves using light. To generate ultrasound, optical fibres are coated in a micron-scale thick layer of an optically-absorbing material, such as carbon-polymer nanocomposites.

Pulsed laser light is targeted at this coating, causing it to heat up and generate an ultrasound wave. This wave then propagates into the body, and is reflected from interfaces within tissue.

The reflected ultrasound waves are received by extremely sensitive optical elements such as Fabry-Pérot cavities, in which light is reflected between two opposing mirrored surfaces.

“By varying the location in the tissue in which the ultrasound wave is generated, signals can be acquired and processed to produce high-resolution pulse-echo ultrasound images in real-time from within the body,” said Desjardins.

Optical ultrasound could also have widespread applications outside medicine. The technology could be used in non-destructive imaging of materials, for example, particularly in environments with high levels of electromagnetic interference, which can present significant challenges to the use of conventional electronic ultrasound transducers, he said.