When doctors are operating on a patient to remove a cancer, they face a major challenge: telling healthy and cancerous cells apart. But a new, as yet unnamed device being developed by researchers at Washington University in St. Louis' School of Medicine could provide a safe, affordable and portable solution.
The team's goggle-based device allows the surgeon to see the cancer cells, glowing blue. Tests have shown it could make visible tumors as small as 1 mm in diameter. To make the cells appear blue, the FDA-approved contrast agent indozyanine is injected into the tumor.
The compact system is battery-operated, wireless, wearable and most importantly, hands-free. A night vision viewer from which it was developed was retrofitted to provide near-infrared excitation and white light illumination simultaneously. The visual data captured by near-infrared (NIR) fluorescence is displayed directly on the eyepiece with adjustable amplification.
The wireless capability, adapted from a battery-operated radio frequency video transmitter, allows the system to transfer real-time video to a remote site, where the wearer's view can be displayed graphically. This enables a remote expert to observe what is happening during the operation from the point of view of the local surgeon, and provide expert feedback and image analysis. This way the system could be applied to point-of-care medical interventions, help generate real-time pathologic assessment of tissues, and even allow for remote medical consulting.
The new eyepiece could represent an improvement on current methods of intra-operative imaging. These are usually expensive, logistically complex, time-consuming and at times risky, as in cases when radioactive tracers are needed. These emit hazardous ionizing radiation to both patients and surgeons. The blue dyes used for visualizing sentinel lymph nodes with the naked eye, for example, can also cause adverse reactions.
The technology has been developed by a team led by Samuel Achilefu, a PhD professor of radiology and biomedical engineering at Washington University in St. Louis. Earlier in February, breast surgeon Julie Margenthaler, an associate professor of surgery at the university, performed a surgery wearing the glasses. “Imagine what it would mean if these glasses eliminated the need for follow-up surgery and the associated pain, inconvenience and anxiety," she said in a press statement.
Currently, surgeons usually remove the tumor and some neighboring tissue that may not include cancer cells. Once analyzed, and if cancer cells are found in the sample, then a second surgery is recommended to remove additional tissue that once again will be tested for cancer. In cases of breast cancer patients, between 20 and 25 percent of those who have lumps removed require a second surgery.
An article with details on the technology behind the device appeared in a recent edition of the Journal of Biomedical Optics.
