Photo credit: Western University
In the operating room, a cardiac surgeon has just begun an open heart procedure on her patient. Beside the operating table, a small cart houses a tiny laser pointed at the patient's brain. During the operation, the laser beams light through the skull to monitor brain activity—and immediately detect possible problems arising. The clinical team can intervene on the spot to prevent any damage.
Bedside neuromonitoring is a completely new use for quantum sensor technology. Developed initially for quantum communication and other quantum physics applications, the single-photon sensitive sensors show potential for improving navigation and in areas such as medical imaging, geological surveying, defence, safety, security and more.
In medicine, this non-invasive tool can be used to guide surgeons doing clinical interventions such as cardiac surgery or carotid endarterectomy that could lead to brain injury. And it will save lives.
"Its capacity to solve clinical problems could open up applications that we can't even envision until users come up with disruptive ideas," says Western University's Dr. Mamadou Diop, associate professor in the Department of Medical Biophysics at the Schulich School of Medicine & Dentistry and scientist at the Lawson Health Research Institute. "This proves the importance of investment in fundamental science, because you never know what might come out of it."
Photo credit: Western University
As project leader for the research to advance bedside neuromonitoring with quantum technology, Dr. Diop works with experts in quantum communication and quantum physics at the National Research Council of Canada (NRC) and the University of Waterloo. This three-party collaboration is critical to the success of the project because each brings disparate yet essential elements to the table.
Funding is provided by the NRC's Internet of Things: Quantum Sensors Challenge program, headed by Dr. Aimee Gunther. "This ground breaking application is a prime example of creative collaborative thinking that is showing orders of magnitude enhancement over existing technologies and that can change people's lives."
Sensitivity is key
Cerebral metabolism is a sensitive marker of brain health. Quantum sensors offer a window into the brain that is inaccessible with traditional imaging techniques.
Today's state-of-the-art technique to gauge the metabolic activity of the body's-tissue cells uses a radioactive substance called a tracer. With this method—positron emission tomography, or PET—patients injected with the tracer undergo imaging in a PET/CT scanner. And because the substance must also be stored and transported in special containers, using this method is complicated, time-consuming and expensive.
Quantum biosensors monitor cerebral oxidative metabolism in real time at the bedside by shining a laser into a patient's head. They can also be deployed in remote areas and cost at least 10 times less than a PET scan.
Dr. Duncan England, research officer in the NRC's ultrafast quantum photonics team, points out that the cameras in these sensors can detect individual photons—the tiniest particles of light. Made of superconducting nanowires, the sensors measure light with unrivalled sensitivity and speed across an unmatched frequency range. And because single-photon-level detection is so sensitive, it's safer for the patient.
"When you shine a laser into the brain through the skull, most of the light is lost in the transfer," Dr. England says. "Quantum sensors can pick up what's left and beam it back to the originating camera in seconds to produce high resolution images.
These sensors increase the sampling rate of the device from one minute to less than a second. And in brain monitoring, that could mean the difference between life and death.
Dr. Thomas Jennewein and his team from the University of Waterloo built the data interface and the software that ensures this biosensor would provide ultrafast imaging data readings rapidly and efficiently, which is crucial for the objective of delivering real-time information.
"It was great to see technologies developed for quantum communications and imaging translate into the exciting area of biomedical sensing," he says. "It's very inspiring to work on a project that will one day help save lives."
Lab work and next steps
Photo credit: Western University
In his lab at Western, Dr. Diop uses 3D "head-mimicking phantoms" to validate the device. The realistic heads mimic actual tissues and skull structure.
The next step is to prove that the device can operate effectively in a physiologically relevant situation by observing it in live pigs, whose heads are roughly the size of human heads. The final stages are to test it on healthy human volunteers, then conduct the first clinical pilot study in humans.
Dr. Diop anticipates that it could take about 3 years until the sensor is ready for production and commercialization by industry and, depending on funding, another 6 to 10 years before it's available on the market.
Dr. Gunther points out that the NRC is at the leading edge of applying quantum photonics to biosensors. "We expect that continuing collaborative R&D between quantum and domain experts will accelerate the commercialization of quantum technologies and their adoption."
This project is supported by grants and contributions awarded through the Collaborative Science, Technology and Innovation Program, administered by the NRC's National Program Office. For more information, send an email to NRC.QuantumSensors-CapteursQuantiques.CNRC@nrc-cnrc.gc.ca.
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