Microscopic robots are a common theme in science fiction. But over the years they’ve become more than that, finding their way into genuine real-life applications ranging from disease prevention to building repairs.
Now, a team of researchers from Canada are turning the attention of these tiny robots to liver cancer, utilising them in conjunction with MRI machines to treat the disease.
Guided by an external magnetic field, a series of miniature biocompatible robots, made of magnetisable iron oxide nanoparticles, can theoretically provide medical treatment in an extremely targeted manner.
This technology, while impressive, has been held back by one big technical issue: the force of gravity of these microrobots exceeds that of the magnetic force. This limits their guidance when the tumour is located higher than the injection site.
“To solve this problem, we developed an algorithm that determines the position that the patient’s body should be in for a clinical MRI to take advantage of gravity and combine it with the magnetic navigation force,” said Dr Gilles Soulez, a researcher at the CHUM Research Centre at Université de Montréal.
“This combined effect makes it easier for the microrobots to travel to the arterial branches which feed the tumour. By varying the direction of the magnetic field, we can accurately guide them to sites to be treated and thus preserve the healthy cells.”
This research could make steps towards changing how interventional radiology treats liver cancers. The most common of which, hepatocellular carcinoma, is responsible for 700,000 deaths per year across the world.
“Our magnetic resonance navigation approach can be done using an implantable catheter-like those used in chemotherapy,” said Soulez. “The other advantage is that the tumours are better visualised on an MRI than on X-rays.”
In the experiment, the team of researchers used 12 pigs to replicate the patient’s anatomical conditions. The microrobots navigated the branches of the animal's hepatic artery, which was targeted by the algorithm, and reached their destination.
And that's not all. “Using an anatomical atlas of human livers, we were able to simulate the piloting of microrobots on 19 patients treated with transarterial chemoembolization,” said Soulez.
“They had a total of 30 tumours in different locations in their livers. In more than 95 per cent of cases, the location of the tumour was compatible with the navigation algorithm to reach the targeted tumour.”
Despite significant strides, clinical application of this kind of technology is still a long way off. The artificial intelligence models need training, with improvements specifically needed in the real-time navigation of the microrobots to the liver.
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