title: Sinogram-based attenuation correction in PET/CT.
abstract: In a typical positron emission tomography/computed tomography (PET/CT) system, the attenuation correction is necessary for PET image reconstruction, which involves a transformation from the CT Hounsfield units (HU) to its linear attenuation coefficient (LAC) at 511 keV. This transformation is usually aided by an empirical bilinear function, followed by the forward projection of the transformed attenuation image. In this paper, we propose a direct method that calculates attenuation factors from CT projections, without using a reconstructed CT image. In this method, the human body is considered as a mixture of three distinct components: air, water and bone. Then, we estimate the proportions of these three components along each x-ray path and restore the attenuation factor at 511 keV with the known water and bone LACs. Our numerical results show that the proposed method produces as accurate estimation as the conventional HU mapping method.
authors.affiliation: Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, NY, USA.
authors.forename: Qingsong
authors.initials: Q
authors.lastname: Yang
authors.affiliation: Department of Physics and Reconstruction, Molecular Imaging Business Unit, United Imaging Healthcare Co., Ltd, Shanghai, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Lu
authors.affiliation: Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, NY, USA.
authors.forename: Yan
authors.initials: Y
authors.lastname: Xi
authors.affiliation: Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, NY, USA.
authors.forename: Wenxiang
authors.initials: W
authors.lastname: Cong
authors.affiliation: Divisions of Thoracic and Cardiac Imaging at Massachusetts General Hospital.
authors.forename: Mannudeep
authors.initials: M
authors.lastname: Kalra
authors.affiliation: Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, NY, USA.
authors.forename: Ge
authors.initials: G
authors.lastname: Wang
mesh_terms: D000005:Abdomen / Q000000981:diagnostic imaging; D000465:Algorithms; D003198:Computer Simulation; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008168:Lung / Q000000981:diagnostic imaging; D008954:Models, Biological; D019047:Phantoms, Imaging; D000072078:Positron Emission Tomography Computed Tomography / Q000379:methods*
keywords: PET/CT; attenuation correction; sinogram