  Clinical tracking systems are popular but typically require specific tracking
markers. During the last years, scanning speed of optical coherence tomography
(OCT) has increased to A-scan rates above 1 MHz allowing to acquire volume
scans of moving objects. Thorefore, we propose a markerless tracking system
based on OCT to obtain small volumetric images including information of
sub-surface structures at high spatio-temporal resolution. In contrast to
conventional vision based approaches, this allows identifying natural landmarks
even for smooth and homogeneous surfaces. We describe the optomechanical setup
and process flow to evaluate OCT volumes for translations and accordingly
adjust the position of the field-of-view to follow moving samples. While our
current setup is still preliminary, we demonstrate tracking of motion
transversal to the OCT beam of up to 20 mm/s with errors around 0.2 mm and even
better for some scenarios. Tracking is evaluated on a clearly structured and on
a homogeneous phantom as well as on actual tissue samples. The results show
that OCT is promising for fast and precise tracking of smooth, monochromatic
objects in medical scenarios.
