Improving imaging of cancerous tissues by reversing time

November 2, 2014
Improving imaging of cancerous tissues by reversing time

As a child, it was fascinating to put a flashlight up to our palms to see the light shine through the hand. Washington University in St. Louis engineers are using a similar idea to track movement inside the body's tissues to improve imaging of cancerous tissues and to develop potential treatments.

Lihong Wang, PhD, the Gene K. Beare Distinguished Professor of Biomedical Engineering at the School of Engineering & Applied Science is applying a novel time-reversal technology that allows researchers to better focus in tissue, such as muscles and organs.

Current high-resolution optical imaging technology allows researchers to see about 1 millimeter deep into the body. Beyond that, the light scatters and obscures the features, which is why we can't see bones or tissue in the hand with a flashlight. To overcome this, Wang and his lab developed , which combines light with acoustic waves, or sound, to form a sharper image, even several centimeters into the skin.

In new research published Nov. 2 in Nature Photonics Advance Online Edition, Wang is now using a new technology called time-reversed adapted-perturbation (TRAP) optical focusing, which sends guiding light into tissue to seek movement. The light that has traversed stationary tissue appears differently than light that has moved through something moving, such as blood. By taking two successive images, they can subtract the light through stationary tissue, retaining only the scattered light due to motion. Then, they send that light back to its original source via a process called time-reversal so that it becomes focused once back in the tissue.

"This can potentially be used in imaging or therapy," Wang says. "For example, focusing pulsed light on port wine stains, which are excessive growth of blood vessels, could remove the stains without damaging the surrounding normal skin."

The video will load shortly
This video shows dynamic focusing onto a moving target inside scattering media. Credit: Lihong Wang, Ph.D.

In 2011, Wang's lab was the first to use ultrasound focusing to provide a virtual, non-invasive internal guide star that allowed them to focus on anything moving in . But TRAP focusing is much more efficient in tracking moving targets, Wang says in the new research. TRAP focusing can enhance and contrast by redistributing and concentrating light on the targets, allowing for images to be taken from greater depths.

Explore further: Researchers develop technique to focus light inside biological tissue

More information: Ma C, Xu X, Liu Y, Wang LV. Time-reversed adapted perturbation (TRAP) optical focusing onto dynamic objects inside scattering media. Nature Photonics, Advanced Online Edition, Nov. 2, 2014. DOI: 10.1038/nphoton.2014.251

Related Stories

High-intensity sound waves may aid regenerative medicine

October 30, 2014

Researchers at the University of Washington have developed a way to use sound to create cellular scaffolding for tissue engineering, a unique approach that could help overcome one of regenerative medicine's significant obstacles. ...

Recommended for you

Understanding nature's patterns with plasmas

August 23, 2016

Patterns abound in nature, from zebra stripes and leopard spots to honeycombs and bands of clouds. Somehow, these patterns form and organize all by themselves. To better understand how, researchers have now created a new ...

Light and matter merge in quantum coupling

August 22, 2016

Where light and matter intersect, the world illuminates. Where light and matter interact so strongly that they become one, they illuminate a world of new physics, according to Rice University scientists.

Measuring tiny forces with light

August 25, 2016

Photons are bizarre: They have no mass, but they do have momentum. And that allows researchers to do counterintuitive things with photons, such as using light to push matter around.

Stretchy supercapacitors power wearable electronics

August 23, 2016

A future of soft robots that wash your dishes or smart T-shirts that power your cell phone may depend on the development of stretchy power sources. But traditional batteries are thick and rigid—not ideal properties for ...

Spherical tokamak as model for next steps in fusion energy

August 24, 2016

Among the top puzzles in the development of fusion energy is the best shape for the magnetic facility—or "bottle"—that will provide the next steps in the development of fusion reactors. Leading candidates include spherical ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.