Breast cancer is the most prevalent non-skin cancer among women. Starting as an abnormality within the breast, the cancer is at risk of spreading to the rest of the body; therefore, early detection of such abnormalities is paramount. Equally as important as detecting them is monitoring them regularly for changes—but do we have the tools necessary to do this?
The answer is yes—and no. Most of the procedures for diagnosis and monitoring—mammograms, breast ultrasounds, breast biopsies, breast MRIs—require expensive equipment. It’s not feasible for these procedures to be performed regularly, or in underdeveloped areas where access to such equipment is rare. Although breast self-examinations are a highly advocated, inexpensive way to detect lesions, it does not provide information that can be recorded and tracked.
Thus was born the need for an alternative method—and responding to that need is BME Ph.D. student Constance Robbins, who is working with Jana Kainerstorfer, assistant professor of BME, to develop a new device. James Antaki, professor of BME, is also a collaborator on this project.
“We’re not trying to replace mammograms,” says Robbins. “If you have results that are inconclusive, but there’s not high enough of a risk to justify an immediate biopsy, then this could be something we could use this device for.”
If you have [mammogram] results that are inconclusive...then this could be something we could use this device for.Constance Robbins, Ph.D. student, Biomedical Engineering, Carnegie Mellon University
The first iteration was called “Palpaid,” a project developed by Molly Blank, a former BME Ph.D. student advised by Antaki. Palpaid was intended to be a handheld device that measured the mechanical properties of a lesion. The device relied on the stiffness of the lesion compared to its surrounding tissue. When pressed against the breast, the device’s flexible, reflective lens would deform around the stiff tissue and capture a topographic image of the deformation, which could then be examined for information on size, shape, stiffness, and location.
Robbins decided to take Palpaid further and measure vascularization, too. Breast lesions are stiff and highly vascularized, meaning they contain greater total hemoglobin concentration than the surrounding softer tissue. But how can something like blood content be measured non-invasively?
The answer is with light. Robbins is using an imaging method called spatial frequency domain imaging (SFDI), where different patterns of light are shone on an area to extract information from the way those patterns are reflected differently. The variations in reflection tell us how much light the tissue can absorb, which in turn depends on the concentration of hemoglobin in the tissue. However, light can only penetrate so far past the surface of the breast—what if a lesion is too deeply embedded?
“If the lesion is too deep, we won’t be able to detect it—that’s why we use compression to decrease the distance from the lesion to our sensors,” says Robbins.
By compressing the tissue and essentially pushing the lesion closer towards the surface of the breast, the light can penetrate further into the tissue, and the device can get a better read on the lesion’s blood content.
Robbins presented her research at the SPIE Photonics West Conference, a conference dedicated to optics, in January 2017. She will finish her required Ph.D. coursework next year and will then devote her time entirely towards research. Having already started the next round of experiments, Robbins hopes to create a consumer electronic device that has the potential to revolutionize breast cancer treatment worldwide.