A Novel Detector Geometry for X-Ray CT

State-of-the-art X-ray computed tomography (CT) scanners all employ the conventional detector geometry which forms an arc concentric to the X-ray source. While each collected projection forms an equiangular dataset, the distance of each projection sample to the iso-center is nonuniformly spaced. During the cone-beam to parallel-beam conversion, both channel-wise and view-wise rebinning are required, leading to a degraded spatial resolution and an increased aliasing artifact. In this article, we propose a novel detector geometry that acquires evenly spaced projection samples relative to the iso-center and only view-wise rebinning is required to form a parallel dataset. To ensure that the detector cell size is independent of the cell position, the source-to-detector distance varies as a function of the detector fan-angle. Each detector module is tilted to guarantee the orthogonality of the detector surface to the X-ray. Extensive computer simulations were performed to demonstrate the efficacy of our design. Spatial resolution was measured with the modulation transfer function (MTF) and the proposed design offers a 12.6% improvement. When the equiangular configuration was retuned to match the spatial resolution, the proposed design exhibits an 8.8% noise reduction. In addition, aliasing artifacts were significantly reduced at locations away from the iso-center.