'Ultra-fine sound beam can work like scalpel'

The ultrasound technology enables far more than glimpses into the womb. For example, doctors routinely use focused sound waves to blast apart kidney stones and prostate tumours.

This is done by pressing sound waves tightly enough to generate heat, says Jay Guo, study co-author and professor of electrical engineering and computer science, mechanical engineering, and macromolecular science and engineering, at Michigan, according to the journal Scientific Reports.

However, the beams produced in this way can be unwieldy, says Hyoung Won Baac, research fellow at Harvard Medical School who worked on the project as a doctoral student in Guo's lab, according to a Michigan statement.

 

"A major drawback of the current strongly focused ultrasound technology is a bulky focal spot, which is on the order of several millimetres," Baac said.

"Therefore, it can be difficult to treat tissue objects in a high-precision manner, for targeting delicate vasculature, thin tissue layer and cellular texture. We can enhance the focal accuracy 100-fold."

The new technology by researchers can blast a beam that can cut with pressure, rather than heat. Guo said that it might be used to conduct painless surgeries as the beam is so finely focused that it could avoid nerve fibres. The technology hasn't been tested in animals or humans yet.

"We believe this could be used as an invisible knife for non-invasive surgery," Guo said.

"Nothing pokes into your body, just the ultrasound beam. And it is so tightly focused, you can disrupt individual cells."

The findings will be presented at the SPIE Photonics West in San Francisco.