Known as a luminary in medical imaging, Dennis L. Parker, PhD is currently devoting much of his time to focused ultrasound. Parker, a professor of Radiology at the University of Utah and Director of the Utah Center for Advanced Imaging Research (UCAIR), is co-leading the development of a high intensity focused ultrasound (HIFU) system for breast tumors.
The project’s origins trace back to 2003 when Utah purchased its first MRI scanner from Siemens. “Because the Siemens MRI scanner was very open as far as its software architecture, our students were able to very, very quickly establish a closed feedback loop feeding images out of the scanner into the ultrasound controlling computer that we had at the time,” Parker recalls. This led to the development of a closed-loop MRI guided focused ultrasound system.
“When Siemens came to visit in 2004, they actually decided to pick up that project and provided some funding,” he notes. At the time, Image Guided Therapy (IGT), a French medical device maker, had just designed a phased-array focused ultrasound transducer.
“Siemens purchased that device and placed it in Utah as IGT’s first large animal focused ultrasound system,” Parker adds. “Ever since that time, we’ve been working with them.”
By 2006, Parker and his collaborators decided that the best candidate site for their system would be the breast, and they applied for funding from the National Institutes of Health to develop a prototype. “It was an academic/industrial partnership,” he says. “We were very lucky. We were funded on the first submittal, which is very rare, but we were delighted.”
His collaborators on the project represent numerous disciplines and several departments at the University of Utah. In addition to Parker, the team includes Robert B. Roemer, PhD from Mechanical Engineering; Douglas Christensen, PhD from Bioengineering; Allison Payne, PhD, Rock Hadley, PhD, Emilee Minalga, PhD, Robb Merrill, PhD and Nick Todd, PhD from UCAIR; Leigh Neumayer, MD from Surgery/Oncology; and many students.
New breast system has unique features
Utah’s system, says Parker, “has a lot of capabilities not found in other breast HIFU systems.” Unique features include the placement of the focused ultrasound transducer. Mounted on flexible bellows made of PlastiDip (an idustrial grade fabrication material), the transducer can be moved into and out of the treatment cylinder as needed. Also unique is that the transducer shoots laterally. The system has a small water box in which the breast is suspended. That box has an array of radio frequency coils around it. According to Parker, this provides “image quality from the MR side [that] is actually very, very good.”
The system’s other major components are an MR-compatible ultrasound generator made by IGT and a Siemens MRI scanner.
Now in prototype form, the system has been tested on phantoms and samples. “From the standpoint of something that could ultimately be used to treat breast cancer, I think this is an excellent potential device,” Parker says. “The advantage of HIFU for breast cancer is that it’s totally noninvasive. It has the opportunity eventually to totally eradicate the disease without any surgical intervention at all.”
A patent application has been filed for the system and further improvements are planned. “There are many problems that still need to be solved,” he notes. “Measuring temperature in fat, which is a major component of breast tissue, has not been solved yet by others. We’ve got a good technique that is starting to work and we’re optimistic that with all these little pieces it’ll be a good system.”
The team, says Parker, will seek funding to develop modifications that improve image quality and enable the system to treat more aspects of breast disease. “Our new design should be able to treat much more of the disease, including many metastatic lesions,” he notes.
Written by Ellen C., McKenna