title: Energy-resolved CT imaging with a photon-counting silicon-strip detector.
abstract: Photon-counting detectors are promising candidates for use in the next generation of x-ray computed tomography (CT) scanners. Among the foreseen benefits are higher spatial resolution, better trade-off between noise and dose and energy discriminating capabilities. Silicon is an attractive detector material because of its low cost, mature manufacturing process and high hole mobility. However, it is sometimes overlooked for CT applications because of its low absorption efficiency and high fraction of Compton scatter. The purpose of this work is to demonstrate that silicon is a feasible material for CT detectors by showing energy-resolved CT images acquired with an 80 kVp x-ray tube spectrum using a photon-counting silicon-strip detector with eight energy thresholds developed in our group. We use a single detector module, consisting of a linear array of 50 0.5×0.4 mm detector elements, to image a phantom in a table-top lab setup. The phantom consists of a plastic cylinder with circular inserts containing water, fat and aqueous solutions of calcium, iodine and gadolinium, in different concentrations. By using basis material decomposition we obtain water, calcium, iodine and gadolinium basis images and demonstrate that these basis images can be used to separate the different materials in the inserts. We also show results showing that the detector has potential for quantitative measurements of substance concentrations.
authors.affiliation: Department of Physics, Royal Institute of Technology, SE-106 91 Stockholm, Sweden.
authors.forename: Mats
authors.initials: M
authors.lastname: Persson
authors.forename: Ben
authors.initials: B
authors.lastname: Huber
authors.forename: Staffan
authors.initials: S
authors.lastname: Karlsson
authors.forename: Xuejin
authors.initials: X
authors.lastname: Liu
authors.forename: Han
authors.initials: H
authors.lastname: Chen
authors.forename: Cheng
authors.initials: C
authors.lastname: Xu
authors.forename: Moa
authors.initials: M
authors.lastname: Yveborg
authors.forename: Hans
authors.initials: H
authors.lastname: Bornefalk
authors.forename: Mats
authors.initials: M
authors.lastname: Danielsson
mesh_terms: D004867:Equipment Design; D006801:Humans; D019047:Phantoms, Imaging; D017785:Photons; D011856:Radiographic Image Enhancement / Q000295:instrumentation*; D012815:Signal Processing, Computer-Assisted / Q000295:instrumentation*; D012825:Silicon / Q000737:chemistry*; D014057:Tomography, X-Ray Computed / Q000295:instrumentation* / Q000379:methods
chemical_list: D012825:Silicon