Researchers at the University of Illinois at Urbana-Champaign and Washington University in St. Louis have developed a surgical camera inspired by the eye of the morpho butterfly. The camera, connected to the goggles worn by a surgeon, sees infrared signals given off by tumor-binding dyes so that the surgeon can remove all of the cancerous tissue. The camera was tested in mice and in human patients with breast cancer.
Although many surgeons rely on sight and touch to find cancerous tissue during surgery, large hospitals or cancer treatment centers may also use experimental near-infrared fluorescent agents that bind to tumors so that the surgeons can see them on specialized displays.
However, these machines are costly, making them difficult for smaller hospitals to procure; very large, making them difficult to fit into an operating suite and integrate smoothly into surgery; and require the lights to be dimmed so that the instruments can pick up the weak fluorescent signal, making it difficult for the surgeons to see.
The morpho butterfly's eye has specialized nanostructures that allow it to see multispectral images, including near-infrared. The research team built its camera with the same kinds of nanostructures, creating a small camera that can simultaneously register regular color images and near-infrared signals without needing to dim the room lights. To make it easy for a surgeon to use, the researchers integrated the camera into surgical goggles. When the surgeon puts on the goggles, it will protect their eyes and at the same time project the fluorescent information whenever they want it.
It is anticipated that the goggles will cost around $200, compared with $20,000 for the cheapest existing FDA-approved instrument. The researchers partnered with surgeons at Washington University to run tests on mice and on humans. The camera was able to find breast-cancer tumors in mice, using a near- infrared fluorescent dye that binds specifically to the type of cancer the mice had. Since the camera can pick up signals beneath the surface of the tissue, the surgeons could even locate tumor sites through the skin. They could image and identify the potential points of interest to minimize the incision.
They also tested the camera for finding sentinel lymph nodes in human patients with breast cancer. Doctors need to find and biopsy or remove all the lymph nodes surrounding a tumor to see if the cancer has spread. They use dyes to make the lymph nodes easier to see. In the study, the surgeons used a common green dye that also emits an infrared signal. The researchers compared how well the physicians could identify the lymph nodes in a patient with breast cancer by looking for green color by eye, and then looking for the infrared signal using the butterfly's-eye camera. The camera found lymph nodes that the surgeons did not see visually, which turned out to be cancerous. This technology is much quicker because one of the advantages of fluorescence, is that you can see through the skin or the tissue to identify nodes.
Next, the researchers are working to integrate their camera with endoscopic camera systems.