A Movable Phantom Design for Quantitative Evaluation of Motion Correction Studies on High Resolution PET Scanners

Head movements during brain imaging using high resolution positron emission tomography (PET) impair the image quality which, along with the improvement of the spatial resolution of PET scanners, in general, raises the importance of motion correction. Here, we present a new design for an automatic, movable, mechanical PET phantom to simulate patients´ head movements while being scanned. This can be used for evaluating motion correction methods. A low-cost phantom controlled by a rotary stage motor was built and tested for axial rotations of 1°-10° with the multiple acquisition frame method. The phantom is able to perform stepwise and continuous axial rotations with submillimeter accuracy, and the movements are repeatable. The scans were acquired on the high resolution research tomograph dedicated brain scanner. The scans were reconstructed with the new 3-D ordered subset expectation maximization algorithm with modeling of the point spread function (3DOSEM-PSF), and they were corrected for motions based on external tracking information using the Polaris Vicra real-time stereo motion-tracking system. The new automatic, movable phantom has a robust design and is a potential quality assessment tool for the development and evaluation of future motion correction methods.