UNC Lineberger researcher, collaborators to test molecular imaging technology

A four-year grant from the National Cancer Institute will fund a pre-clinical study of molecular ultrasound imaging technology that researchers believe can better gauge whether cancer treatments are working.

UNC Lineberger researcher, collaborators to test molecular imaging technology click to enlarge Paul Dayton, PhD

Researchers from the UNC Lineberger Comprehensive Cancer Center and three other institutions have been awarded more than $2 million to test proposed new molecular imaging technology that they believe can more effectively show whether cancer treatments are working.

The researchers were awarded the four-year grant from the National Cancer Institute for a pre-clinical study testing the proposed new molecular ultrasound imaging technology. Paul Dayton, PhD, a UNC Lineberger member and a professor at the University of North Carolina at Chapel Hill and North Carolina State University Joint Department of Biomedical Engineering, said the researchers believe ultrasound molecular imaging technology has cost and safety advantages compared with other imaging technologies. Ultrasound is lower cost, portable, and doesn’t involve the use of radiation – so it could potentially be used earlier and more frequently to gauge whether patients are responding to treatment, Dayton said.

“The idea is that if you can identify whether or not a tumor is responding earlier, you could change that patient’s course of treatment and potentially treat the cancer more effectively, earlier, while also reducing their exposure to potentially toxic treatments that perhaps aren’t working,” Dayton said.

The technology is designed to detect changes down to the molecular level. While traditional ultrasound equipment can produce images of anatomical features of the body and is currently used to measure tumor size and structural characteristics, Dayton said the proposed new technology uses sound waves to detect the presence of a particular molecular marker. In particular, their system is proposed to detect a marker present on the blood vessels of solid cancer tumors.

 “Cancer cells actually stimulate the body to grow new blood vessels through a process called angiogenesis,” Dayton said. “That process of blood vessel growth is associated with different molecular changes, and it’s those molecular changes that we are targeting for detection with our ultrasound molecular imaging.”

The researchers plan to develop the technology and then to test it in the final two years of the grant. They plan to study its use in dogs undergoing cancer treatment at NC State University’s College of Veterinary Medicine and at the Colorado State University Flint Animal Center. Dayton is the co-principal investigator with Mark Borden, an associate professor of mechanical engineering at the University of Colorado Boulder and the project lead. The grant is the next installment of funding awarded for the project following a four-year grant awarded in 2008.

The researchers' technology is proposed to detect changes at the molecular level using “targeted contrast agents” that bind to receptors on the vessels connected to tumors. Designed in the form of small spheres called “microbubbles,” the agents vibrate at a specific frequency that allows them to be detected by the ultrasound technology.

“When the microbubble experiences a pulse of ultrasound, it vibrates like a guitar string or a bell, and it makes its own frequency,” Dayton said. “So that means that the contrast agent has a certain ultrasound signature that allows you to detect it, and separate that signal.”

UNC’s main role in the project is to develop a mechanism to allow the ultrasound equipment to capture three-dimensional images and to optimize the imaging technology for use in dogs, Dayton said.

“If it is successful, this technology could allow patients to be treated more effectively sooner, so their chances of recovery are better,” he said. “Still, this technology is still in the earlier stages of development, and more testing needs to be done before beginning human testing.”

Funding for the first year of the four-year grant is guaranteed, while future year funding allotments depend on NCI’s federal appropriation.