Motion Correction for Simultaneous PET/MR Brain Imaging Using a RF-Penetrable PET Insert

Here, we individually study two components required to properly track and correct for subject motion with the intention of integrating the methodology into a radiofrequency penetrable brain dedicated PET insert for MRI. The motion tracking component of the work studied the accuracy of a camera-based approach in which a checkerboard marker was mounted on a stage with three degrees of freedom. Fixed translational and rotational inputs were provided and compared to the estimates derived from the optical tracking of the checkerboard reference. The motion correction step implemented the multiple acquisition frames (MAF) method by using a set of three-point sources which were precisely translated to three positions and rotated to a final position for a total four separate data points. Each position was reconstructed separately and integrated to produce the MAF correction. The 3D FWHM and CNR for each individual frame and MAF output were calculated. The MAF method provided a minimum CNR gain of ~3 when compared to any single frame.