Ultrasound equipment doesn't come easy, often taking the shape of clunky contraptions that cost tens or hundreds of thousands of dollars. In a bid to make these invaluable medical machines more accessible, engineers in Canada have developed a new type of ultrasound device the size of a Band-Aid, with the potential of a similarly scaled down price tag.

Generally speaking, ultrasound machines make clever use of piezoelectric crystals as a transducer, which rapidly change shape in response to an electric current and give out vibrations as a result. These vibrations, or sound waves, are emitted into the body until they hit a boundary and are bounced back. The same crystals convert the returning sound waves into electrical currents, which in turn can be processed into an image.

Now scientists at the University of British Columbia (UBC) have come up with a new way of doing things that might make the fabrication of ultrasound technology simpler and cheaper. The breakthrough relies on the use of polymer resin in place of the piezoelectric crystals, which can be used to craft tiny vibrating drums called polyCMUTs, that serve as the transducer.

"Transducer drums have typically been made out of rigid silicon materials that require costly, environment-controlled manufacturing processes, and this has hampered their use in ultrasound," said study lead author Carlos Gerardo, a PhD candidate in electrical and computer engineering at UBC. "By using polymer resin, we were able to produce polyCMUTs in fewer fabrication steps, using a minimum amount of equipment, resulting in significant cost savings."

In followup experiments, the team reports that the device generated sonograms as sharp, if not sharper, than piezoelectric-powered transducers. Around the size of the Band-Aid, the device requires little power and is also flexible, meaning it could open up new possibilities in the medical realm, or even be built into clothing.

"Since our transducer needs just 10 volts to operate, it can be powered by a smartphone, making it suitable for use in remote or low-power locations," says Gerardo. "And unlike rigid ultrasound probes, our transducer has the potential to be built into a flexible material that can be wrapped around the body for easier scanning and more detailed views–without dramatically increasing costs."

We have seen other promising approaches to reinventing ultrasound, with a US$2,000 device that displays ultrasound images on an iPhone one notable, recent example. The UBC researchers, however, say their technology could lower the price to as little as $100. From here, they are looking to build a set of prototypes to explore the various potential uses of the new technology, and then onward to clinical testing.

"You could miniaturize these transducers and use them to look inside your arteries and veins," says study co-author Robert Rohling. "You could stick them on your chest and do live continuous monitoring of your heart in your daily life. It opens up so many different possibilities."

The research was published in the journal Nature Microsystems & Nanoengineering.

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