TU‐E‐110‐01: Inverse Geometry CT
Purpose: Computed tomographic imaging has made tremendous progress in recent decades but challenges remain, including dose efficiency and avoiding cone beam artifacts in rapid volumetric imaging. The goal of this research is to explore Inverse Geometry CT (IGCT) as a potential solution to these problems.Methods: Rather illuminating the entire object with a single source, IGCT uses a distributed array of sources, each illuminating a portion of the volume. Two approaches have been studied, one using a scanned anode source (SS‐IGCT) and another using an array of discrete sources each with its own electron emitter (MS‐IGCT). The sequential illumination of subvolumes allows a “virtual bowtie” wherein each source has its own optimized intensity as a function of angle. Results: Results show that distributed sources in the axial direction can readily control cone beam artifacts. A gantry‐based MS‐IGCT system has been built and initial images have been collected. Compared to a conventional system, the virtual bowtie concept can significantly reduce effective dose for the same image quality. A key challenge with IGCT is achieving high x‐ray statistics since only a fraction of the object is illuminating in any instant. Thus, the method is well suited to lower dose scanning. Conclusion: IGCT uses distributed x‐ray sources to ensure sufficient sampling and to sculpt the illuminating x‐ray field. Initial results are promising. Research sponsored by GE Healthcare. The learning objectives are to familiarize the audience with 1. Principles of Inverse Geometry CT (IGCT) 2. Advantages of IGCT 3. Challenges and disadvantages of IGCT 4. Progress in IGCT to‐date