Mammography and its cousin technology digital tomosynthesis have saved countless lives by helping diagnose breast cancer when it is treatable. Magnetic Resonance Imaging (MRI) is also used at UC Davis Health for breast imaging, often in women who are at high risk of breast cancer. Now, a third option is emerging as a promising diagnostic technology: Breast computed tomography (CT).
Breast CT is more comfortable for women. During a mammogram breasts are compressed, which can be painful. With the breast CT system, women lie on their stomachs on a table containing holes through which breasts drop into a pendant position for scanning.
The fully three-dimensional, high-resolution breast CT scanner has the potential to revolutionize breast cancer detection by catching it in its earliest stages.
What makes it different is its ability to detect mass lesions, with adequate detection of microcalcifications, or small calcium deposits, as well. Both mass lesions and microcalcifications can be indicators of potential early-stage breast cancer.
UC Davis researchers recently studied the ability of breast CT to detect these small calcium deposits. They used a computer simulation to embed likenesses of microcalcifications of different sizes and locations into breast CT images, then used artificial intelligence to track them. The results were published in the journal Medical Physics.
“Breast CT is a promising tool for the early detection of breast cancer,” said Shadi Aminololama-Shakeri with the UC Davis Department of Radiology breast imaging program. “Visualization of microcalcifications, which may be the size of grains of sand and smaller, have posed a challenge since the development of the early breast CT prototypes. We are continuing to see improvement with the scanner so we can confidently use it in the clinical realm with the goal of early detection for optimal treatment of breast cancer.”
A Canadian public company, was established to manufacture the UC Davis-based design of the breast CT scanner on a larger scale. The company has licensed several UC Davis-owned patents.
While the commercial scanner's design differs from the model created at UC Davis, the experience of UC Davis researchers played a significant role in shaping the new scanner.
"As an example of the type of academic and industry partnerships we are trying to grow here at the cancer center, we are getting closer to celebrating the commercialization of the breast CT scanner that was invented here at the Boone Lab," said UC Davis Comprehensive Cancer Center Director Primo "Lucky" Lara Jr.
In 2004, John Boone and his team at UC Davis were the first in the world to perform a cone beam breast CT examination on a patient. The latest generation of the CT scanner, designed and tested at UC Davis, achieved nearly four times the spatial resolution of earlier scanners.
"The fourth UC Davis scanner, called the Doheny, is more advanced than earlier systems that we developed," said Boone, a distinguished professor in the UC Davis Department of Radiology and the Department of Biomedical Engineering. "This is due to the combination of a pulsed X-ray source, a smaller focal spot, a higher resolution flat-panel detector, and more advanced CT reconstruction algorithms."
The Doheny scanner has now evolved into the IzoView, which is in the final stages of completion at the new Izotropic manufacturing facility established in Sacramento. The company plans to engage in U.S. Food and Drug Administration (FDA) trials in the next year. Boone and Aminololama-Shakeri have a financial interest in Izotropic, with Boone serving as a director.
"We're very excited about the prospect of this economic development project and look forward to following its progress," Lara said.
UC Davis breast CT clinical trials
UC Davis has conducted phase II clinical trials with the Doheny scanner to compare its performance with mammography, breast tomosynthesis, and MRI. Over 600 patients have participated in the trials by undergoing breast CT scans, and researchers are currently evaluating the results.
The breast CT program at UC Davis has been funded by the National Institutes of Health and other research organizations, attracting over $20 million in external research funding.
“With dozens of graduate students, colleague radiologists in the breast imaging center and staff researchers, we have improved the design of the UC Davis breast CT systems over the past 25 years, with a commensurate improvement in imaging performance,” Boone said. “The Izotropic breast CT system [IzoView] is the culmination of the UC Davis efforts and is designed to be a cost-effective clinical tool.”
Boone added that he expects the scanner to improve the lives of innumerable breast cancer patients after Izotropic achieves FDA clearance for the system.
