Why scientists think diamonds could help identify cancer that has spread

UK scientists have designed a new way to trace breast cancer’s malignant route through the body – using diamonds.

When cancer spreads, its first stop is often the nearby lymph nodes. Doctors typically use radioactive tracers or fluorescent dyes to make the cancer cells visible and identify just how much the disease has metastasised.

But these approaches have some drawbacks: Some patients are allergic to the dyes, and some hospitals are not equipped for the extra precautions required when handling radioactive materials.

Now, researchers have built a new type of sensor that they say offers a non-toxic and non-radioactive alternative.

During or before breast cancer surgery, they said doctors could inject a magnetic tracer fluid into a patient’s tumour. The liquid then travels to the lymph nodes, along with the metastasised cancer cells.

To track down the fluid and identify which nodes should be surgically removed, doctors would rely on a magnetic field sensor with a tiny diamond at the tip, the researchers said. Diamonds have nitrogen vacancy centres, or colour centres, that can sense magnetic fields.

These colour centres “allow the diamond to detect very small changes in magnetic field and give the diamonds a lovely pink colour,” Gavin Morley, one of the study’s authors and a physics professor at the University of Warwick, said in a statement.

Morley’s team got the sensor's tip down to just 10 millimetres, which they said makes it the first diamond sensor to be able to find magnetic tracer fluid while still being small enough to use in surgeries.

The researchers published their findings in the journal Physical Review Applied. They did not disclose any funding from Endomagnetics Ltd, which makes the magnetic tracer they used.

Dr Stuart Robertson, a breast cancer surgeon in England, said magnetic sensors are now used regularly to identify whether breast cancer has spread.

The new approach, he said, could help “optimise magnetic technology further”.