A Stationary Head CT Prototype with CNT X-ray Source Arrays

X-ray Computed Tomography (CT) is an indispensable imaging modality in the medical field, notably in the diagnosis of traumatic brain injury and brain hemorrhage. Existing clinical CT systems, all of which use rotating x-ray sources, are too complex for practical deployment in resource-poor environments. A stationary array of sources and detectors with sufficient angular coverage and focal spot density could potentially simplify the image acquisition hardware and generate adequate projection data for CT reconstruction. In this study, we present a stationary head CT (s-HCT) prototype which combines projection data from three separate but parallel imaging planes into a complete volumetric iterative CT reconstruction. The fully operational scanner features three carbon nanotube (CNT) x-ray source arrays with 45 distributed focal spots each, and an Electronic Control System (ECS) for high speed control of the x-ray exposure from each focal spot. Projection data is acquired by translating the object along the z-axis at constant speed to expose all three imaging planes for the full dataset As the object is moving at constant speed, 135 views are collected every 0.44 s (cycle time). The 3D iterative reconstruction designed specifically for the s-HCT configuration has been used to produce phantom images for initial assessment of the spatial resolution. A linear collimator was designed and constructed for the reduction of cross-plane scatter. Finally, the prototype has been able to acquire these images in scan times comparable to those of commercial scanners (<1min), indicating the CNT x-ray and s-HCT technologies are developed enough for clinical trials.