Study Of Motion Gating In 3D Pet Imaging By Geometric Sensitivity

The PET (positron emission tomography) image quality can be degraded due to respiratory motion artifacts, gating techniques utilizing the tracking motion information are able to reduce the image degradation. This paper presents a new gating method that utilizes the geometric sensitivity feature of a 3D PET scanner system operating in list event acquisition mode. The count rate detected by PET scanner from a given body organ will depend on the axial location of the organ in the FOV (field of view) due to the geometric sensitivity. As a result, the respiratory motion phase can be determined from count rate changes for motion gating. This method has several advantages over the existing methods. It only uses LOR (line of response) events and is non-invasive; No additional hardware device systems and no additional patient preparation are required. Using GATE (GEANT4 Application Tomographic Emission) with a configuration simulating a Philips Allegro PET system demonstrates that the geometric sensitivity method is able to reduce motion artifacts.