Scientists have developed a diamond-based sensor that could make it easier for doctors to detect the spread of cancer.
Researchers at the University of Warwick have created a handheld device that is designed to trace tiny magnetic particles injected into the body.
The scientists said this offers a non-toxic alternative to radioactive tracers and dyes currently used in hospitals.
Metastasis, when cancer cells spread from the original tumour to other parts of the body, is one of the most serious challenges in cancer treatment.
Doctors often rely on tests to see whether the cancer has reached the lymph nodes – the areas of tissue that filter fluid in your body for harmful substances – which can guide decisions about surgery and further care.
The findings, published in Physical Review Applied, describe how diamonds can be used to build a highly sensitive sensor capable of identifying the magnetic tracer fluid injected into a tumour.
This fluid, made up of iron oxide nanoparticles, travels through the body alongside cancer cells, revealing whether they have reached the lymph nodes, the researchers said.
Lead author Alex Newman, a PhD student in Warwick University’s physics department, said the new tool could improve the way doctors find cancer in keyhole and endoscopic surgery.
“There is a real demand for versatile non-toxic means of finding cancer,” he said.
“For this new diamond-based sensor, we managed to get the size of the sensor head down to just 10 millimetres, which means it is the first diamond sensor to be able to detect magnetic tracer fluid while being small enough for endoscopic use and keyhole surgery.”
Mr Newman added that the device was extremely sensitive, capable of detecting just one hundredth of the typical dose of magnetic tracer fluid.
The design uses a diamond measuring only half a cubic millimetre alongside a small permanent magnet, the scientists said
They added that this compact structure means there is no need for bulky electronics, allowing the sensor to be used by hand in operating rooms.
Professor Gavin Morley, who leads the research group, said the breakthrough was possible thanks to nitrogen vacancy centres inside the diamond.
“These allow the diamond to detect very small changes in the magnetic field and give the diamonds a lovely pink colour,” he said.
He added that the technology could also have uses beyond medicine, including in spacecraft and fusion power.
Current techniques for tracing cancer cells rely on radioactive tracers, which not all hospitals can access, or blue dyes, which trigger allergic reactions in some patients, the researchers said.
Clinicians involved in this new project believe the new diamond sensor could help avoid these complications.
Stuart Robertson, a consultant breast cancer surgeon at University Hospitals Coventry and Warwickshire, said he was already using magnetic localisation in his work. He added that it offers more advantages over traditional techniques.
Researchers say the device could eventually be applied to various cancers, including lung, liver, colorectal and oesophageal tumours.
