Implementation of precise bed motion control and super-sampling acquisition for LaPET scanner

Abstract

A typical whole-body PET scanner performs data acquisition of a patient from multiple bed positions with overlap between adjacent bed positions. An alternative acquisition mode, continuous or near-continuous bed motion acquisition, has a number of advantages over the traditional step-and-shoot mode, including uniform axial sensitivity and elimination of axial resolution artifacts. To support the super-sampling acquisition, a smart patient bed allowing accurate translations in three perpendicular axes and a synchronization mechanism between data acquisition and bed motion are required. In this study, we investigate the incorporation of super-sampling techniques (in both axial and transverse directions) in the continuous bed motion acquisition to further take advantage of the acquisition mode. To implement the super-sampling data acquisition, precise motion control and synchronized data acquisition are crucial. We develop a real-time precise bed motion control based on the NI SoftMotion architecture to upgrade the manual control, and we generate digital pulses and recorded them as control-events in list-mode data for motion synchronization. A Lab VIEW graphical user interface is developed to coordinate the super-sampling acquisitions with the synchronized bed motion. We adapt our blob-based list-mode reconstruction package for super-sampling reconstructions by incorporating different offsets for different data sets in the forward- and backward-projection at each iteration or sub-iteration.