Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New Technology Focuses Diffuse Light Inside Living Tissue

07.01.2015

Lihong Wang, PhD, continues to build on his groundbreaking technology that allows light deep inside living tissue during imaging and therapy.

In the Jan. 5 issue of Nature Communications, Wang, the Gene K. Beare Professor of Biomedical Engineering at Washington University in St. Louis, reveals for the first time a new technique that focuses diffuse light inside a dynamic scattering medium containing living tissue. In addition, they have improved the speed of optical focusing deep inside tissue by two orders of magnitude. This improvement in speed is an important step toward noninvasive optical imaging in deep tissue and photodynamic therapy.


Washington University in St. Louis

Lihong Wang, PhD

In the new research, Wang and his team have built on a technique they developed in 2010 to improve the focusing speed of time-reversed ultrasonically encoded (TRUE) optical focusing for applications in living tissue. To focus light, the engineers use a virtual internal guide star at the targeted location. By detecting the wavefront of light emitted from the guide star, they can determine an optimum phase pattern that allows scattered light moving along different paths to focus at the targeted location.

When light is shined into living biological tissue, breathing and blood flow changes the optical interference, or speckle pattern, which can cause previous methods to focus diffuse light inside scattering media to fail. Scientists have to act quickly to get a clear image.

The new TRUE technology combines two techniques: focused ultrasonic modulation and optical phase conjugation. Researchers use a type of mirror to record then time-reverse the ultrasound-modulated light emitted from the ultrasonic focus to achieve the best focus. Previously, technology limited the speed of TRUE focusing to no more than 1 Hz.

To overcome this obstacle, the team used a fast-responding photorefractive crystal that is sensitive to light at the 790-nanometer wavelength, making it suitable to focus light deep into biological tissue. The new TRUE technology is able to focus light inside a dynamic medium with a speckle correlation time as short as 5.6 milliseconds. The improved speed allowed Wang to achieve the first optical focusing of diffuse light inside a scattering medium containing living biological tissue.

Going forward, the team plans to implement the system in a reflection configuration, where light is shined and detected on the same side of the tissue.

The School of Engineering & Applied Science at Washington University in St. Louis focuses intellectual efforts through a new convergence paradigm and builds on strengths, particularly as applied to medicine and health, energy and environment, entrepreneurship and security. With 91 tenured/tenure-track and 40 additional full-time faculty, 1,300 undergraduate students, more than 900 graduate students and more than 23,000 alumni, we are working to leverage our partnerships with academic and industry partners — across disciplines and across the world — to contribute to solving the greatest global challenges of the 21st century.

Liu Y, Lai P, Ma C, Xu X, Grabar A, Wang LV. Optical focusing deep inside dynamic scattering media with near-infrared time-reversed ultrasonically encoded (TRUE) light. Nature Communications, online Jan. 5, 2015. DOI: 10.1038/ncomms6904.

Funding from the National Institutes of Health (DP1 EB016986 and R01 CA186567) supported this research.

Contact Information
Julie Flory
Asst. Vice Chancellor for Campus Communications
Phone: 314-935-5408
julie.flory@wustl.edu

Julie Flory | newswise
Further information:
http://www.wustl.edu

More articles from Medical Engineering:

nachricht Biocompatible 3-D tracking system has potential to improve robot-assisted surgery
17.02.2017 | Children's National Health System

nachricht Real-time MRI analysis powered by supercomputers
17.02.2017 | University of Texas at Austin, Texas Advanced Computing Center

All articles from Medical Engineering >>>

The most recent press releases about innovation >>>

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

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Switched-on DNA

20.02.2017 | Materials Sciences

Second cause of hidden hearing loss identified

20.02.2017 | Health and Medicine

Prospect for more effective treatment of nerve pain

20.02.2017 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>