Rapiscan Systems, Inc., has developed a real-time tomography (RTT) stationary-gantry CT system to fulfill TSA requirements for screening accessible property at speed of the passenger. Similar in concept to the Rapiscan RTT110 stationary-gantry CT system for hold-baggage, the newly developed smaller tunnel system has been redesigned from the ground up. The goal is to achieve a high-speed, small-footprint and low-cost system that exceeds the performance of currently deployed dual-view checkpoint systems.
We propose an FBP reconstruction algorithm for a stationary gantry CT scanner with distributed sources. The sources are fired in quasi-random order to improve data completeness across the field of view (FOV). The downsides of that are two-fold. The neighboring sources are fired non-sequentially, so the view derivative should be avoided. Second, the angular distribution of rays through each voxel is non-uniform and varies across the FOV. To overcome these challenges we incorporate a weight function into an FDK-type reconstruction algorithm, and integrate by parts to avoid view differentiation. Results of experiments with simulated data confirm that a properly selected weight significantly reduces irregular view sampling streaks.