title: A combination-weighted Feldkamp-based reconstruction algorithm for cone-beam CT.
abstract: The combination-weighted Feldkamp algorithm (CW-FDK) was developed and tested in a phantom in order to reduce cone-beam artefacts and enhance cranio-caudal reconstruction coverage in an attempt to improve image quality when utilizing cone-beam computed tomography (CBCT). Using a 256-slice cone-beam CT (256CBCT), image quality (CT-number uniformity and geometrical accuracy) was quantitatively evaluated in phantom and clinical studies, and the results were compared to those obtained with the original Feldkamp algorithm. A clinical study was done in lung cancer patients under breath holding and free breathing. Image quality for the original Feldkamp algorithm is degraded at the edge of the scan region due to the missing volume, commensurate with the cranio-caudal distance between the reconstruction and central planes. The CW-FDK extended the reconstruction coverage to equal the scan coverage and improved reconstruction accuracy, unaffected by the cranio-caudal distance. The extended reconstruction coverage with good image quality provided by the CW-FDK will be clinically investigated for improving diagnostic and radiotherapy applications. In addition, this algorithm can also be adapted for use in relatively wide cone-angle CBCT such as with a flat-panel detector CBCT.
authors.affiliation: Radiological Protection Section, National Institute of Radiological Sciences, Japan. smori1@partners.org
authors.forename: Shinichiro
authors.initials: S
authors.lastname: Mori
authors.forename: Masahiro
authors.initials: M
authors.lastname: Endo
authors.forename: Shuhei
authors.initials: S
authors.lastname: Komatsu
authors.forename: Susumu
authors.initials: S
authors.lastname: Kandatsu
authors.forename: Tomoyasu
authors.initials: T
authors.lastname: Yashiro
authors.forename: Masayuki
authors.initials: M
authors.lastname: Baba
mesh_terms: D000465:Algorithms; D021621:Imaging, Three-Dimensional / Q000379:methods*; D016247:Information Storage and Retrieval / Q000379:methods; D019047:Phantoms, Imaging; D011856:Radiographic Image Enhancement / Q000379:methods; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D036542:Tomography, Spiral Computed / Q000379:methods*