Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New Technique Allows Ultrasound To Penetrate Bone, Metal

24.11.2014

Researchers from North Carolina State University have developed a technique that allows ultrasound to penetrate bone or metal, using customized structures that offset the distortion usually caused by these so-called “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. “This has been difficult in the past because the skull distorts the ultrasound’s acoustic field.”


Using a new technique, “it’s as if the aberrating layer isn’t even there,” says researcher Yun Jing. Image credit: Yun Jing.

“These metamaterials could also be used in industrial settings,” says Dr. Yun Jing, an assistant professor of mechanical and aerospace engineering at NC State and senior author of the paper. “For example, it would allow you to use ultrasound to detect cracks in airplane wings under the wing’s metal ‘skin.’”

Ultrasound imaging works by emitting high frequency acoustic waves. When those waves bounce off an object, they return to the ultrasound equipment, which translates the waves into an image.

But some materials, such as bone or metal, have physical characteristics that block or distort ultrasound’s acoustic waves. These materials are called aberrating layers.

The researchers addressed this problem by designing customized metamaterial structures that take into account the acoustic properties of the aberrating layer and offsetting them. 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.

In simulations, only 28 percent 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 percent of ultrasound wave energy passes through the aberrating layer.

“In effect, it’s as if the aberrating layer isn’t even there,” Jing says.

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.

The paper, “An Anisotropic Complementary Acoustic Metamaterial for Cancelling out Aberrating Layers,” is published online in the open access journal Physical Review X. The paper was co-authored by Drs. Jun Xu and Nicholas Fang at MIT. Jing acknowledges financial support from NC Space Grant via a New Investigator award. Xu and Fang acknowledge support from the Office of Naval Research under grant N00014-13-1-0631.

-shipman-

Note to Editors: The study abstract follows.

“An Anisotropic Complementary Acoustic Metamaterial for Cancelling out Aberrating Layers”

Authors: Chen Shen and Yun Jing, North Carolina State University; Jun Xu and Nicholas X. Fang, Massachusetts Institute of Technology

Published: Nov. 19 in Physical Review X (open access)


DOI: http://dx.doi.org/10.1103/PhysRevX.4.041033

Abstract: In this paper, we investigate a type of anisotropic, acoustic complementary metamaterials (CMM) and their application in restoring acoustic fields distorted by aberrating layers. The proposed quasi 2-D, non-resonant CMM consists of unit cells formed by membranes and side branches with open ends. Simultaneously anisotropic and negative density is achieved by assigning membranes facing each direction (x- and y-direction) with different thicknesses while the compressibility is tuned by the side branches. Numerical examples demonstrate that, the CMM, when placed adjacent to a strongly aberrating layer, could acoustically cancel out that aberrating layer. This leads to dramatically reduced acoustic field distortion and enhanced sound transmission, therefore virtually removing the layer in a noninvasive manner. In the example where a focused beam is studied, using the CMM, the acoustic intensity at the focus is increased from 28% to 88% of the intensity in the control case (without the aberrating layer and the CMM). The proposed acoustic CMM has a wide realm of potential applications, such as cloaking, all angle anti-reflection layers, ultrasound imaging, detection and treatment through aberrating layers.

Matt Shipman | EurekAlert!

More articles from Medical Engineering:

nachricht 'Memtransistor' brings world closer to brain-like computing
22.02.2018 | Northwestern University

nachricht MRI technique differentiates benign breast lesions from malignancies
20.02.2018 | Radiological Society of North America

All articles from Medical Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Attoseconds break into atomic interior

A newly developed laser technology has enabled physicists in the Laboratory for Attosecond Physics (jointly run by LMU Munich and the Max Planck Institute of Quantum Optics) to generate attosecond bursts of high-energy photons of unprecedented intensity. This has made it possible to observe the interaction of multiple photons in a single such pulse with electrons in the inner orbital shell of an atom.

In order to observe the ultrafast electron motion in the inner shells of atoms with short light pulses, the pulses must not only be ultrashort, but very...

Im Focus: Good vibrations feel the force

A group of researchers led by Andrea Cavalleri at the Max Planck Institute for Structure and Dynamics of Matter (MPSD) in Hamburg has demonstrated a new method enabling precise measurements of the interatomic forces that hold crystalline solids together. The paper Probing the Interatomic Potential of Solids by Strong-Field Nonlinear Phononics, published online in Nature, explains how a terahertz-frequency laser pulse can drive very large deformations of the crystal.

By measuring the highly unusual atomic trajectories under extreme electromagnetic transients, the MPSD group could reconstruct how rigid the atomic bonds are...

Im Focus: Developing reliable quantum computers

International research team makes important step on the path to solving certification problems

Quantum computers may one day solve algorithmic problems which even the biggest supercomputers today can’t manage. But how do you test a quantum computer to...

Im Focus: In best circles: First integrated circuit from self-assembled polymer

For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.

In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...

Im Focus: Demonstration of a single molecule piezoelectric effect

Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale

Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

2nd International Conference on High Temperature Shape Memory Alloys (HTSMAs)

15.02.2018 | Event News

Aachen DC Grid Summit 2018

13.02.2018 | Event News

How Global Climate Policy Can Learn from the Energy Transition

12.02.2018 | Event News

 
Latest News

Basque researchers turn light upside down

23.02.2018 | Physics and Astronomy

Finnish research group discovers a new immune system regulator

23.02.2018 | Health and Medicine

Attoseconds break into atomic interior

23.02.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>