Who?

• Dr. Stuart Foster, Professor and Associate Chairman, Department of Medical Biophysics, Sunnybrook Health Sciences Centre and University of Toronto
• Foster is also the Chief Scientific Officer and Chairman of the Board of VisualSonics Inc.

What?

• Foster has won the $25,000 Manning Award of Distinction for inventing and developing an ultrasound microimaging system for mice; the system has expanded the scope of medical research possible

Where?

• Foster works out of Sunnybrook Health Sciences Centre in Toronto, Ontario
• VisualSonics is based in Toronto, Ontario
• Vevo 770™ users include major research centres in Canada and the United States; the University of Paris, France; the Max Planck Institute, Germany; as well as organizations in China, Australia, Korea, and Japan

When?

• Foster has been working with ultrasound for clinical and pre-clinical imaging for 30 years; he began to focus on microimaging about 15 years ago
• VisualSonics released the Vevo 770™ in late 2005 after about six years of development

Why?
The Vevo 700™ is an ultrasound microimaging system used to view tissue changes and blood flow within a living mouse. The one-of-a-kind ultrasound system produces highly detailed images in real-time, with capability for three-dimensional visualization.

Dr. Stuart Foster of the Sunnybrook Health Sciences Centre, Toronto, and founder of spin-off company, VisualSonics Inc., designed the technology in collaboration with a talented team of research engineers and graduate students. Their efforts have opened significant new horizons for medical research.

Because the system is non-invasive, researchers can more humanely track changes in an individual mouse over time, instead of sacrificing many mice at sequential time points in an experiment. "We don't want to use any more mice than are absolutely necessary in any given study," explains Foster.

We share 95 percent of our genes with mice, and with the completion of the mouse genome and human genome sequencing projects, the mouse has emerged as the model of choice for genetic research. The third generation of Dr. Foster's imaging system, the Vevo 770™, allows researchers to study the effects of genetic changes in mice from their early development as embryos through to adulthood.

The Vevo 770™ has broad applications in biology, particularly in mouse models of human disease. It can be used to study the efficacies of drugs and the progression of cancers and heart disease.

Foster notes that similar technology could be used for microimaging of human structures. "In the future, applications related to ophthalmology, skin imaging and intravascular imaging may be feasible," he says.

Foster's research team is part of an international consortium of imaging scientists who are developing various microimaging technologies, including MR imaging and PET, to study the mouse model system.

How?
Ultrasound imaging works much like bats' use of echolocation: Echoes, or reflected sound waves, are used to construct a spatial image.

Conventional ultrasound imaging—the technology used to monitor a developing fetus—uses sound waves beyond the frequency that humans can hear. High frequency sound waves directed at an object bounce back, and a transducer converts the returning sound waves into a visual picture.

The key technology in the Vevo 770™ scanner is the transducer, which transmits and receives the ultrasound waves.

In order to apply ultrasound to microimaging—a method of viewing microscopic structures— Foster's team had to design a transducer that could transmit and receive extremely high frequency sound waves. They also had to develop a signal processor, among other pieces of equipment, to work with the new transducers.

Because Foster's imaging system uses ultra-high frequency sound waves, it can resolve objects less than the diameter of a human hair.

Foster says that examining a mouse with the Vevo 770™ is not unlike examining a human with conventional ultrasound. The researcher applies gel to an anaesthetized mouse, which lies on a "mouse couch." A scan head moves back and forth across the mouse's body, and a monitor reveals the inner structures of the mouse.

During the ultrasound scan, an ECG monitor and temperature monitor measure the mouse's vital signs.

"The key thing is to make sure that the mouse is comfortable and as close to its normal state as possible," notes Foster, adding that "If you've got an excited mouse, its heart rate is going to be completely different than its normal situation."

The Vevo 770™ builds on Foster's 15 years of work in ultrasound microimaging. "It goes back a long way," says Foster. "Like most things, you start with a simple idea and build on it, gradually recognizing the potential, and then develop new and improved ways of using the technique or approach."

This year, the Ernest C. Manning Awards Foundation will award a total of $165,000 in prize money. Four awards, totaling $145,000, will go to leading Canadian innovators. Another $20,000 will go to Young Innovators with winning projects at the 2006 Canada-Wide Science Fair.

The Foundation was established in 1980 in the name of prominent Alberta statesman, Ernest C. Manning, to promote and support Canadian innovators. Since 1982, the Foundation has presented over $3.6 million in prize money through its annual awards program (www.manningawards.ca).