Johns Hopkins University researchers recently wowed with their smart tissue, autonomous robot (STAR). It turns out the STAR’s biocompatible, near-infrared 3D tracking system is innovative, too.

The tracking system – which uses near-infrared fluorescent (NIRF) markers – could improve both manual and robot-assisted surgery and interventions, according to a new study.

The study compared the 3D tracking system with standard optical tracking methods.

A development team from Sheikh Zayed Institute for Pediatric Surgical Innovation and Children’s National Health System tracked the speeds at 1 mm per second and saw that tracking accuracies of 1.61 mm degraded to 1.71 mm if the markers were covered in blood and tissue. The team was able to demonstrate feasibility in vivo and showed the 3D tracking of tissue and surgical tools within a millimeter accuracy in ex vivo experiments.

“A fundamental challenge in soft-tissue surgery is that target tissue moves and deforms, becomes occluded by blood or other tissue, which makes it difficult to differentiate from surrounding tissue,” said Axel Krieger, senior author on the study. “By enabling accurate tracking of tools and tissue in the surgical environment, this innovative work has the potential to improve many applications for manual and robot-assisted surgery.”

Using small biocompatible NIRF markers with fused plenoptic and a near-infrared camera tracking system, the tracking system allows for 3D tracking despite blood and tissue occlusion in a constantly changing surgical environment. The researchers suggest that because near-infrared light penetrates deeper than visual light, the imaging is able to see through the occlusion problems.

“This work describes the ‘super human eyes’ and a bit of ‘intelligence’ of our STAR robotic system, making tasks such as soft tissue surgery on live subjects possible,” said Peter C. Kim, VP and associate surgeon in chief of Sheikh Zayed Institute.

The researchers hope to test the tracking system in other image-guided medical interventions.

The study was published in the journal IEEE Transactions on Biomedical Engineering and was funded by the National Institutes of Health.

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