NEW MATERIAL IMPROVING ULTRASOUND TECHNOLOGY

 

 

Ultrasound Imaging Technology Enhanced with Golden Nanorods Encased in Polymer

 

Ultrasound technology could soon undergo a significant enhancement that would enable it to generate high quality, high-resolution images, due to the development of a new key material.

The material, which converts ultrasound waves into optical signals that can be used to produce an image, is the result of a collaborative effort by Prof. Vladislav Yakovlev, a professor in the department of biomedical engineering at Texas A&M University (College Station, USA; www.tamu.edu), and researchers from King’s College London (UK;www.kcl.ac.uk), The Queen’s University Belfast (Ireland; www.qub.ac.uk), and the University of Massachusetts Lowell (USA; www.uml.edu). Their study findings appear in the March 1, 2013, issue of the journal Advanced Materials.

The modified substance, known as a “metamaterial,” offers substantial advantages over traditional ultrasound technology, which generates images by transforming ultrasound waves into electrical signals, Prof. Yakovlev explained.

Although that technology has advanced throughout the years similar to the improvement in sonogram images, it is still mostly constrained by bandwidth and sensitivity limitations, he noted.These limitations, he added, have been the chief obstacle when it comes to producing high-quality images that can serve as powerful diagnostic tools. The metamaterial developed by Prof.Yakovlev and his colleagues is not subject to those limitations, primarily because it converts ultrasound waves into optical signals rather than electrical ones. The optical processing of the signal does not limit the bandwidth or sensitivity of the transducer (converter), which is vital for generating very detailed images, Prof. Yakovlev said. “A high bandwidth allows you to sample the change of distance of the acoustic waves with a high precision,” Prof. Yakovlev noted. “This translates into an image that shows greater detail. Greater sensitivity enables you to see deeper in tissue, suggesting we have the potential to generate images that might have previously not been possible with conventional ultrasound technology.”

Meaning, this new material may enable ultrasound devices to see what they have not yet been able to see. That advancement could significantly boost a technology that is utilized in a range of biomedical applications. In addition to being used for visualizing fetuses during regular and emergency care, ultrasound is used for diagnostic purposes in events of trauma and even as a means of breaking up tissue and accelerating the effects of drugs therapies. Whereas this research is not yet ready for incorporation into ultrasound technology, it has effectively shown how conventional technology can be substantially enhanced by using the newly engineering material created by his team, Prof. Yakovlev reported.

The substance, he noted, is comprised of golden nanorods embedded in a polymer called a polypyrrole. An optical signal is sent into this compound where it interacts with and is changed by incoming ultrasound waves before passing through the material. A detection device would then read the changed optical signal, analyzing the changes in its optical characteristics to process a higher resolution image, he clarified.

“We developed a material that would enable optical signal processing of ultrasound,” Prof. Yakovlev concluded. “Nothing like this material exists in nature so we engineered a material that would provide the properties we needed. It has greater sensitivity and broader bandwidth. We can go from 0–150 MHz without sacrificing the sensitivity. Current technology typically experiences a substantial decline in sensitivity around 50 MHz.

This metamaterial can efficiently convert an acoustic wave into an optical signal without restricting the bandwidth of the transducer, and its potential biomedical applications represent the first practical implementation of this metamaterial.”

New Ultrasound Applications Detects Early Response to Pancreatic Cancer Therapy

New Ultrasound Applications Detects Early Response to Pancreatic Cancer Therapy

By Medimaging International staff writers Posted on 06 Mar 2013

In a recent study, investigators utilized dynamic contrast enhanced-perfusion imaging (DCE-PI) and ultrasonic molecular imaging (USMI) to gauge response to therapy for pancreatic cancer.

The research was published in the January 2013 issue journal Technology in Cancer Research and Treatment. Paul Dayton, PhD, University of North Carolina (UNC) Lineberger Comprehensive Cancer Center (Chapel Hill, USA), and senior author of the study, said, “What we found is that using two noninvasive technologies, we can detect response to therapy earlier than by relying on tumor volume changes. Having new noninvasive, inexpensive technologies available to measure response to therapy earlier during the course of treatment would be a significant advance in the ability to tailor a person’s treatment to improve outcomes.”

Dr. Dayton, a UNC associate professor of biomedical engineering, worked with Jen Jen Yeh, M.D, an associate professor of surgery and pharmacology, to assess the imaging technologies on human pancreatic cancer in a preclinical model. Both investigators are members of the Lineberger Comprehensive Cancer Center.

USMI has the ability to depict noninvasively the biologic processes at the cellular and molecular levels. It accomplishes this with the use of targeted contrast agents, which are markers that bind to specific proteins expressed on cancer cells within the body. These contrast agents enable a conventional ultrasound system to identify signals from cancer cells that would otherwise be undetectable.

Ultrasound DCE-PI is a technique used noninvasively to track the blood flow in the microcirculation. Because growing tumors require abnormally increased blood flow, alterations in blood vessel structure or density can provide data regarding tumor malignancy. The researchers employed a drug that suppresses a protein specific to tumors. They then used the imaging applications to gauge the response of two different tumors, one known to respond to the drug therapy, and a second known not to respond. The findings indicated that USMI was able to detect molecular signs of tumor response to therapy after only two days.

A change in blood flow in the tumor was seen to detect response after day 14 using DCE-PI. Over the same period, standard volume measurements were not able to detect therapeutic response, and prior studies suggested that volume measurements do not become indicative of response until approximately 28 days. Therefore, these modalities revealed a substantial improvement in the early identification of tumor response to therapy, using contrast enhanced ultrasound imaging.

The contrast agents for USMI currently in clinical trials in Europe for cancer imaging, however, they are not yet available in the United States.
Related Links:
University of North Carolina Lineberger Comprehensive Cancer Center