Spectral CT using multiple balanced K-edge filters Journal Article

Authors: Rakvongthai, Y.; Worstell, W.; El Fakhri, G.; Bian, J.; Lorsakul, A.; Ouyang, J.
Article 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.
Journal Title: IEEE Transactions on Medical Imaging
Volume: 34
Issue: 3
ISSN: 1558-254X; 0278-0062
Publisher: Unknown  
Journal Place: United States
Date Published: 2015
Start Page: 740
End Page: 747
Language: eng
Notes: LR: 20160303; GR: R01 CA165221/CA/NCI NIH HHS/United States; GR: R43 EB017591/EB/NIBIB NIH HHS/United States; GR: R43-EB017591/EB/NIBIB NIH HHS/United States; GR: T32 EB013180/EB/NIBIB NIH HHS/United States; GR: T32-EB013180/EB/NIBIB NIH HHS/United States; JID: 8310780; NIHMS666766; OID: NLM: NIHMS666766; OID: NLM: PMC4349342; 2014/09/19 [aheadofprint]; ppublish