The next-generation CT architecture?

We present a new system architecture for X-ray computed Tomography (CT). A multi-source inverse-geometry CT scanner is composed of a large distributed X-ray source with an array of discrete electron emitters and focal spots, and a high frame-rate flat-panel X-ray detector. In this work we study the advantages and the challenges of this new architecture. We predict potential breakthroughs in volumetric coverage, dose efficiency, and spatial resolution. We also present experimental results obtained with a universal benchtop system. I. INTRODUCTION HIRD-generation CT architectures are approaching fundamental limits. Spatial resolution is limited by focal spot size and detector cell size. Temporal resolution is limited by mechanical constraints on gantry rotation speed, and alternative geometries such as electron-beam CT and two- tube-two-detector CT come with severe tradeoffs in terms of image quality, dose efficiency and complexity. Image noise is fundamentally linked to patient dose, and dose efficiency is limited by finite detector efficiency and by limited spatio- temporal control over the X-ray flux. Finally, volumetric coverage is limited by detector size, scattered radiation, conebeam artifacts, heel effect, and over-scan. The concept of multi-source inverse geometry CT (IGCT) breaks through several of the above limitations. The proposed architecture has several advantages compared to third-generation CT: the detector is small and can have a high detection efficiency, the spatial resolution is more consistent throughout the field-of- view, scatter is minimized even when eliminating the anti- scatter grid, the X-ray flux from each source can be modulated to achieve an optimal noise-dose tradeoff, and the geometry offers very large coverage without cone-beam artifacts. In this work we present the fundamentals of IGCT along with a number of recent simulation and measurement results.