Comparison of external motion tracking systems for PET list-mode reconstruction

The present improvement that we see III 3D medical scanner technology including increasing spatio-temporal resolution and increasing signal-to-noise ratio underlines the need for reliable motion correction. Many motion correction schemes assume that the motions are known [1-3]. However, a reliable markerless tracking system is not trivial to provide and to our knowledge not presently existent.

The Polaris Vicra optical tracking system (Northern Digital Inc.) is generally used with PET brain imaging and has been demonstrated to work very well on phantoms [4]. However, it suffers from the necessary attachment of markers to the subject introducing image artifacts on human scans. We have previously designed a camera-based structured light (SL) system for 3D head tracking used with the high resolution research tomograph (HRRT, Siemens, Knoxville, USA) [5].

The system was modified to use invisible light and the accuracy was demonstrated similar to a commercial system [6]. Presently, we show the SL system integrated with the HRRT PET scanner ready for PET motion correction. We show a comparison study with the Polaris Vicra based on list-mode motion corrected [7].