NC State Creates Technique Allowing Ultrasound to Penetrate Bone, Metal

Researchers from North Carolina State University (NC State) have found away around ultrasound’s inability to penetrate bone and metal. Using customized structures, the researchers have created “metamaterial structures” that take into account the acoustic properties of the layers that block/distort ultrasound’s waves. These blockages are known as “aberrating layers.”

“We’ve designed complementary metamaterials that will make it easier for medical professionals to use ultrasound for diagnostic or therapeutic applications, such as monitoring blood flow in the brain or to treat brain tumors, ” says Tarry Chen Shen, a Ph.D. student at NC State and lead author of a paper on the work, in the November 20, 2014 news release. “This has been difficult in the past because the skull distorts the ultrasound’s acoustic field.”

“The metamaterial structure uses a series of membranes and small tubes to achieve the desired acoustic characteristics. The researchers have tested the technique using computer simulations and are in the process of developing and testing a physical prototype.”

According to the news release, in simulations, only 28% of ultrasound wave energy makes it past an aberrating layer of bone when the metamaterial structure is not in place. But with the metamaterial structure, the simulation shows that 88% of ultrasound wave energy passes through the aberrating layer.

The scientists indicate that the technique can be used for ultrasound imaging, as well as therapeutically…such as using ultrasound to apply energy to brain tumors in order to burn them.