Novel SLAM-Based Markerless Motion Tracking of Conscious Unrestrained Rodents in PET
Motion-compensated positron emission tomography
(PET) has the potential to improve translational investigations by
allowing animals to behave normally and respond to external
stimuli. Several groups have demonstrated the feasibility of
performing motion-compensated brain PET on rodents, obtaining
the necessary head motion data using marker-based techniques.
However, markerless motion tracking would simplify animal
experiments, be less invasive, and potentially provide more accurate
pose estimates over a greater range of motion. We describe a
markerless stereo motion tracking system and demonstrate the
feasibility of using this system to obtain highly accurate (< 0.2 mm)
pose estimates for realistic motion of a taxidermied rat head. The
system is based on the simultaneous localization and mapping
(SLAM) framework used in mobile robotics and involves building a
consistent set of landmarks on the head for pose estimation. Pose
measurements using the markerless system were approximately 10
times more accurate than a state-of-the-art marker-based system.
Planning of experiments to validate markerless tracking in
microPET imaging of awake animals is currently underway.