An algorithm can show how patients should best be positioned in order to optimize microrobot treatment for cancerous tumors deep inside the body, a proof-of-concept study indicates.
Artificial intelligence improved the ability to guide biocompatible robots made of iron oxide nanoparticles through blood vessels to the liver and deliver a treatment known as transarterial chemoembolization (TACE).
TACE is one of the main ways liver cancers such as advanced hepatocellular carcinoma are treated, cutting off the blood supply to tumors while delivering chemotherapy on site.
Studies involving pigs and then simulated in patients showed that using the algorithm for body positioning could more than double the ability of microbiotic, drug-eluting beads to reach their target destination.
The findings are published in the journal Science Robotics.
Researcher Gilles Soulez, director of the University of Montreal radiology, radio-oncology and nuclear medicine department explained that the algorithm directs how a patient should be positioned during clinical magnetic resonance imaging (MRI) to take advantage of gravity and the magnetic navigational force.
“This combined effect makes it easier for the microrobots to travel to the arterial branches which feed the tumour,” he said. “By varying the direction of the magnetic field, we can accurately guide them to sites to be treated and thus preserve the healthy cells.”
The algorithm showed whether to position 12 living pigs face up, down or on their sides so that gravity assisted in delivering roughly 2000 drug-eluting beads via hepatic arteries to the target liver lobes.
The distribution ratio of the microrobots in the right liver lobe increased from 44.7% to 86.4% while that for the left lobe rose from 52.2% to 84.1% using the algorithm.
Following their passage through multiple vascular bifurcations, the number of microrobots reaching four target liver lobes increased between 1.7 and 2.6 fold compared with animals that were not repositioned.
Using an anatomical atlas of the liver, the researchers then simulated the piloting of microrobots in 19 patients with hepatocellular carcinoma treated with TACE.
“They had a total of thirty tumours in different locations in their livers,” said Soulez.
“In more than 95 per cent of cases, the location of the tumour was compatible with the navigation algorithm to reach the targeted tumour.”
The team believes the navigation method proposed has several advantages in the clinic, such as eliminating the need for repeat invasive catheterizations in cases of liver embolization.
It could also allow more localized treatment that better protects surrounding healthy tissues.
