title: Spectral CT using multiple balanced K-edge filters.
abstract: Our goal is to validate a spectral computed tomography (CT) system design that uses a conventional X-ray source with multiple balanced K-edge filters. By performing a simultaneously synthetic reconstruction in multiple energy bins, we obtained a good agreement between measurements and model expectations for a reasonably complex phantom. We performed simulation and data acquisition on a phantom containing multiple rods of different materials using a NeuroLogica CT scanner. Five balanced K-edge filters including Molybdenum, Cerium, Dysprosium, Erbium, and Tungsten were used separately proximal to the X-ray tube. For each sinogram bin, measured filtered vector can be defined as a product of a transmission matrix, which is determined by the filters and is independent of the imaging object, and energy-binned intensity vector. The energy-binned sinograms were then obtained by inverting the transmission matrix followed by a multiplication of the filter measurement vector. For each energy bin defined by two consecutive K-edges, a synthesized energy-binned attenuation image was obtained using filtered back-projection reconstruction. The reconstructed attenuation coefficients for each rod obtained from the experiment was in good agreement with the corresponding simulated results. Furthermore, the reconstructed attenuation coefficients for a given energy bin, agreed with National Institute of Standards and Technology reference values when beam hardening within the energy bin is small. The proposed cost-effective system design using multiple balanced K-edge filters can be used to perform spectral CT imaging at clinically relevant flux rates using conventional detectors and integrating electronics.
authors.forename: Yothin
authors.initials: Y
authors.lastname: Rakvongthai
authors.forename: William
authors.initials: W
authors.lastname: Worstell
authors.forename: Georges
authors.initials: G
authors.lastname: El Fakhri
authors.forename: Junguo
authors.initials: J
authors.lastname: Bian
authors.forename: Auranuch
authors.initials: A
authors.lastname: Lorsakul
authors.forename: Jinsong
authors.initials: J
authors.lastname: Ouyang
mesh_terms: D003198:Computer Simulation; D005374:Filtration; D006801:Humans; D019047:Phantoms, Imaging; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000295:instrumentation* / Q000379:methods*; D013052:Spectrometry, X-Ray Emission; D014057:Tomography, X-Ray Computed / Q000295:instrumentation* / Q000379:methods* / Q000592:standards