Optical coherence tomography as highly accurate optical tracking system

Optical coherence tomography (OCT) guided laser cochleostomy enables the ablation accuracy on tens of micrometer scale and therefore also requires a high patient tracking accuracy on the same order of magnitude, which however exceeds the ability of the conventional optical or electromagnetic tracking systems. We have developed a novel approach of using OCT itself as a highly accurate optical tracking system by ablating tiny artificial landmarks surrounding the cochleostomy on the target bone surface and locating them in the online acquired 3D OCT Volumes. The mechanism enables a direct tracking of the target area with respect to the laser optics while the conventional systems rely on indirect tracking of the markers or sensors attached to the regions of interest. The new approach has achieved an overall tracking accuracy of 22.8±14.9μm (mean absolute error) and 27.2μm (root mean square), which is one order of magnitude higher than the conventional tracking system-based setups.