FAYETTEVILLE, Ark. — University of Arkansas engineering researchers have designed and built the archetype of a microwave-imaging system that could lead to a new method of breast-cancer detection. The system applies the same principles and technology used to detect buried land mines.

Further hardware and software development of the technology could lead to production of an inexpensive, portable and patient-comfortable system that will provide three-dimensional images of tumors.

“Malignant cells grow randomly, according to no rule,” said Magda El-Shenawee, UA associate professor of electrical engineering. “That’s a major issue with breast-cancer detection. When the various pieces of our project come together, the microwave system will find tumors and provide sharp, three-dimensional images of their size and shape.”

The microwave-imaging system will have many advantages over other breast cancer detection methods. Because the system provides sharp, three-dimensional images of all hard objects, it will help radiologists distinguish between tumors and benign hard tissue, which is something that cannot always be determined with traditional X-rays. The system also will not emit ionizing radiation. Compared to mammograms and magnetic resonance imaging equipment, the microwave system will be inexpensive, small and mobile, which will allow health-care workers to reach women in rural areas and underdeveloped countries. Finally, the system will be more comfortable for the patient because it will not require compressing the breast to gather data. 

El-Shenawee and Fred Barlow, also an associate professor of electrical engineering, have worked side by side to design, build and test a system that transmits and receives electromagnetic waves that travel through soft tissue and bounce off hard objects. Barlow and his graduate students Faisal Magableh and Mahita Attaluri constructed the system’s hardware, which includes two sensors -- a transmitter and receiver -- and a rotating, mechanical device that holds the sensors and enables researchers to send and receive electromagnetic waves from many angles. It also captures scattering waves that bounce off hard objects. Controlled by a computer, the rotating device is a critical component in gathering data to create three-dimensional images.

El-Shenawee and her graduate students have developed and continue to design software to accompany the hardware. While sending and receiving electromagnetic waves from many angles, the hardware gathers a huge amount of data. The custom software quickly interprets, or translates, the data from “signatures,” the word referring to any signal that indicates the presence of an object.

“You might say the hardware gathers the hay, and then the software reveals whether there’s a needle, how big it is and where it is,” Barlow said.

For many years, El-Shenawee’s research focused on the use of algorithms and other rigorous mathematical equations to analyze how electronic waves scatter as they bounce off rough surfaces. She also calculated electric and magnetic currents on the surface of an object. Her research focused on radar systems designed to detect land mines. When funding for research into land-mine detection discontinued, El-Shenawee decided to apply her expertise in computational and theoretical electromagnetics to biology instead of geology.

“Land mines and tumors have two important things in common,” El-Shenawee said. “They’re both hidden and they both kill. All I needed to do was change the parameters of my equations from geological to biological.”

The researchers have tested the system in an environment that simulates breast tissue. They filled a tank with soybean oil, which has approximately the same consistency as blood and fat tissue in the breast. The researchers suspended a glass ball in the oil and have used the rotating device to send and receive electromagnetic waves through the oil and collect data from the ball.

As El-Shenawee mentioned, the project has many components. She and Barlow have graduate students working on several pieces of the system. Attaluri is currently developing a method to calibrate the hardware. This effort includes measuring the scattered electric fields, magnitude and phase. Measurements will have a common reference point once the system is calibrated. El-Shenawee said they will begin experimenting with objects of varying shapes, sizes and densities when the calibration is finished.

Payam Rashidi, El-Shenawee’s graduate student, has designed imaging software to reconstruct the size, shape and location of the tumor. Shruti Pandalraju and Douglas Woten, also El-Shenawee’s graduate students, are working on several techniques to make the software more robust and efficient.

Gokul Talapanunuri, yet another graduate student of El-Shenawee’s, is designing a cup that would hold the breast. As part of the design, the sensors would be placed on the inside walls of the cup. The interior surface of the cup will be smooth and fit around the breast so that it will not be uncomfortable for women, El-Shenawee said.  Once the cup design is proven efficient using computer simulations, the new sensor design will be fabricated.

Another important component of the project is the effort to create smaller sensors to replace the bulky sensors currently used in the experiment. El-Shenawee recently received a three-year, $470,000 grant from the National Science Foundation to work with a team of researchers at the University of Mississippi to design, develop and test small sensors that are compatible with El-Shenawee’s software.

A radiologist who specializes in breast-cancer detection has joined the research project to provide consultation to the engineers on the anatomy and physiology of the breast.

The primary project is funded by the Arkansas Biosciences Institute and the Women’s Giving Circle at the University of Arkansas. In three years, after the project with the Mississippi engineers is complete, El-Shenawee and Barlow hope to apply for human clinical trials.

Barlow and El-Shenawee do not want their research to discourage women from getting an annual mammogram. But, if it materializes, microwave imaging will have many advantages over other breast cancer detection methods. Most women who’ve had a mammogram will agree that the procedure, which presses the breast between two plates, is not comfortable. This procedure would not be necessary with microwave imaging.

Moreover, with mammograms, which are traditional X-rays, radiologists sometimes have difficulty distinguishing dense, normal tissue from a possible tumor. In addition to providing sharp, three-dimensional images of all hard objects, microwave imaging would distinguish between tumors and benign hard tissue. Mammograms also emit ionizing radiation, which means they produce an electrical charge that can lead to unnatural chemical reactions inside cells.

“Being exposed to a very small dose of radiation is definitely a safer bet than to not have a mammogram and risk breast cancer,” Barlow said. “But not being exposed to any radiation would be better yet.”

Finally, mammograms and MRIs are expensive and employ large, bulky equipment. The microwave-imaging system would be inexpensive, small and mobile, all of which are critical advantages to reaching women in Third-World countries with few medical clinics.