Normalization coefficient computing for continuous bed motion acquisition

With the addition of variable bed speed capabilities, continuous bed motion (CBM) becomes an acquisition generalization for axial sensitivity modeling and therefore a flexible tool in local image quality adjustment. In this paper, we describe the principles behind CBM mode planning and its influence on image reconstruction. The data correction method underwent the most changes compared to the commonly used step and shoot (S&S) mode. The CBM normalization array computing accommodates for activity decay, variable dead time correction, and the fact that various detector pairs acquire the same data for different durations of time. Computing the normalization array is performed simulating the movement of an object through the scanner, assisted by the monitoring of basic scanner acquisition parameters such as the singles rate. The sensitivity, which is the number of counts acquired per image plane modeling, is an intrinsic part of normalization computing. Basic equations to estimate acquisition time at matched sensitivity between mono speed CBM and S&S mode are presented. The CBM feature was implemented on a Siemens clinical scanner and initial studies of phantoms and patients are presented.