Abstract ID: 17117 Title: 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