When removing a brain tumour, the distinction between healthy tissue and cancer isn’t visible to the naked eye. Even advanced imaging can miss what hides between those boundaries. For years, this limitation meant surgeons could never be fully sure whether every cancer cell was gone. But a new Montreal-made device called SENTRY is changing that. Co-developed by the Montreal-based company Reveal Surgical, Dr. Kevin Petrecca, and professor Frédéric Leblond at Polytechnique Montréal, SENTRY uses artificial intelligence (AI) and light-based spectroscopy to detect whether tissue is cancerous in real time, during surgery. When the surgeon touches the device to a spot in the brain, it analyzes the tissue and gives a near-instant answer: tumour or normal. As Dr. Petrecca explains, SENTRY “tells you what’s tumour 98.7% of the time” and can likely “extend a patients life two to five times longer than expected”.
Acting like a sophisticated second pair of eyes, the tool can inform surgeons beyond what human vision and current brain scans are capable.
AI Meeting the Operating Room
The use of AI in the operating room has been a shift which is already underway. For instance, at MarinHealth Medical Center, an AI-based anatomy-mapping platform has been used to take data from a patient’s CT scans and generates 3D images of affected blood vessels for aortic aneurysm repair. In another paper by researchers affiliated with the Chinese PLA General Hospital, they found that an AI–based 3D preoperative planning system for total hip arthroplasty improved the accuracy of implant replacement compared to 2D models.
AI as a tool is often described in abstract terms, demonstrated by the above examples, but using SENTRY it is saving lives in a very tangible way. For instance, patient Peter Ross was given 14 months to live following diagnosis of a brain tumour, but with the help of SENTRY during a surgical procedure to remove his tumour, “it’s given me [Peter Ross] the rest of my life”.
A Montreal Success Story
SENTRY is the product of over a decade of collaboration between academic researchers, surgeons, engineers, and Reveal Surgical. This collaboration therefore reflects Montreal’s strength in both neuroscience and artificial intelligence. To further support this, The Neuro was the first academic institute in the world to fully adopt Open Science, which is a research
approach that promotes free sharing of data to speed up discoveries. When paired with Montreal’s globally recognized AI ecosystem, breakthroughs like SENTRY become inevitable.
The Future
SENTRY still awaits FDA approval, with a pivotal trial likely taking place in May 2026. And it’s not just for the brain. Researchers are already exploring how the same device can identify cancerous tissue in the breast, lungs, and other organs. The goal? A universal surgical companion, specifically one that helps surgeons around the world remove cancer more accurately and completely.
What SENTRY represents is a bridge between clinical vision and robust engineering. These tools are not replacing the surgeon but rather reinforcing them. This tool is evidence of a quiet revolution happening right now in Montreal, with startups rapidly emerging and new technologies changing the future of medicine.
And for people like Peter Ross, that future has already arrived. “I take every extra day that’s given to me to go out and walk, and just enjoy life,” he said. “Because I owe that to this surgery.”
Abhay is a second-year master’s student in pharmacology and therapeutics, with a bachelor’s degree in psychology. He always seeks to learn more, and his research interests are notably neuropharmacological mechanisms of action, how public policy influences medicine, and the psychological basis of decision-making.
Part of the OSS mandate is to foster science communication and critical thinking in our students and the public. We hope you enjoy these pieces from our Student Contributors and welcome any feedback you may have!
