Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Duke engineers developing ultrasound devices combining 3-D imaging with therapeutic heating

07.11.2005


Duke University engineers are developing technology that may enable physicians to someday use high frequency ultrasound waves both to visualize the heart’s interior in three dimensions and then selectively destroy heart tissue with heat to correct arrhythmias.



"No one else has developed a way for ultrasound to combine therapy and imaging in a catheter, let alone 3-D imaging," said Stephen Smith, the biomedical engineering professor who heads the project at Duke’s Pratt School of Engineering.

Smith’s group described work that developed initial laboratory prototypes in two research papers published in October 2005 in the journal "IEEE Transactions on Ultrasonics, Ferroelectronics and Frequency Control" and the journal "Ultrasonic Imaging."


In an interview, he said his group’s technique may improve on doctors’ most widely used method for destroying -- or "ablating" -- aberrant tissue that makes hearts beat irregularly. That current technique employs radio waves emitted from the end of an electrode probe that touches and excessively heats tissue selected for destruction.

After threading that internal probe into the heart through arteries, physicians must now rely on fluoroscopic imaging -- X-ray movies -- to help point the device. "However, a fluoroscope cannot image soft tissue at all," Smith said. "So the heart is just a fuzzy background." Under those circumstances, fluoroscopy can provide physicians "only a very gross guidance," he added.

Duke biomedical engineers previously pioneered techniques rendering the kind of soft tissue internal images that enable fetuses to be seen in the womb. They have also pioneered the use of ultrasound to create 3-D images of the heart and other organs.

During the past five years other researchers have followed up by developing tiny internal ultrasound imaging probes than can provide physicians better visual guidance than X-rays for internal surgery, Smith said. But those previous tiny probes acquire only two-dimensional images, which still have shortcomings for pinpoint tissue ablation, he said.

Meanwhile, other researchers have separately crafted probes using stronger ultrasound waves to heat internal tissues for ablation rather than for imaging. But combining ablation with 3-D imaging in one device is new, he said.

"The nice thing about ultrasound ablation is that you don’t have to touch the tissue," Smith said. "The sound waves propagate through the blood and can ablate the tissue from a distance of a centimeter or two."

His group’s new work builds on its previous success at miniaturizing ultrasound 3-D imaging probes to a dime-sized array of hundreds of individual ultrasound sound sending and receiving elements, called transducers. Such probes are small enough to insert inside the esophagus to render images of the whole heart.

Smith said his team has now built dual-function imaging-plus-ablation ultrasound probes as small as three millimeters -- less than half the size of a dime. "We started using very tiny cables, fitting as many as two hundred into a three millimeter catheter," he said. "This advance in cable technology has allowed us to incorporate both 3-D imaging and ablation in the same catheter.

"The ability to build these tiny matrix arrays is a technology that we’ve developed at Duke for the past decade and now the ultrasound community is following in our footsteps."

In another paper prepared for an October 2003 IEEE ultrasonics symposium, Smith and his former graduate student Kenneth Gentry -- now a postdoctoral researcher at the University of Wisconsin -- described using a prototype device to first image and then raise the temperature of a tissue-mimicking rubber by 25 degrees Fahrenheit. That temperature increase was enough to ablate real tissue, he said. According to that earlier symposium paper, the prototype was also ablation tested on a piece of beef muscle and imaging tested within a fixed sheep heart.

According to Smith, the ablation beam emerging from the same 112-transducer array was 50 times more energetic than the imaging beam. "So far, we’ve been taking turns at imaging for an instant and than ablating in the next instant," he said.

He acknowledged that further miniaturization and other design work will be necessary to build a device small enough to be inserted through vascular pathways into real hearts for visualization and ablation trials.

"We’ve had the design intuition that allows us to do and describe some preliminary experiments," he said. "But we have not yet made a practical device that could even be used in a live animal."

Monte Basgall | EurekAlert!
Further information:
http://www.duke.edu

More articles from Agricultural and Forestry Science:

nachricht Cascading use is also beneficial for wood
11.12.2017 | Technische Universität München

nachricht The future of crop engineering
08.12.2017 | Max-Planck-Institut für Biochemie

All articles from Agricultural and Forestry Science >>>

The most recent press releases about innovation >>>

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

Im Focus: Long-lived storage of a photonic qubit for worldwide teleportation

MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.

Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...

Im Focus: Electromagnetic water cloak eliminates drag and wake

Detailed calculations show water cloaks are feasible with today's technology

Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...

Im Focus: Scientists channel graphene to understand filtration and ion transport into cells

Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.

To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...

Im Focus: Towards data storage at the single molecule level

The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.

Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...

Im Focus: Successful Mechanical Testing of Nanowires

With innovative experiments, researchers at the Helmholtz-Zentrums Geesthacht and the Technical University Hamburg unravel why tiny metallic structures are extremely strong

Light-weight and simultaneously strong – porous metallic nanomaterials promise interesting applications as, for instance, for future aeroplanes with enhanced...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

 
Latest News

Long-lived storage of a photonic qubit for worldwide teleportation

12.12.2017 | Physics and Astronomy

Multi-year submarine-canyon study challenges textbook theories about turbidity currents

12.12.2017 | Earth Sciences

Electromagnetic water cloak eliminates drag and wake

12.12.2017 | Power and Electrical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>