title: Quantitative assessment of four-dimensional computed tomography image acquisition quality.
abstract: The purpose of the present work was to describe the development and validation of a series of tests to assess the quality of four-dimensional (4D) computed-tomography (CT) imaging as it is applied to radiation treatment planning. Using a commercial respiratory motion phantom and a programmable moving platform with a CT phantom, we acquired 4D CT datasets on two commercial multislice helical CT scanners that use different approaches to 4D CT image reconstruction. Datasets were obtained as the platform moved in various patterns designed to simulate breathing. Known inserts in the phantom were contoured, and statistics were generated to evaluate properties important to radiation therapy--namely, accuracy of phase-binning, shape, volume, and CT number. Phase-binning accuracy varied by as much as 5% for a 4D procedure in which images were reconstructed and then binned, but exhibited no variation for a 4D procedure in which projections were binned before reconstruction. The magnitude of geometric distortion was found to be small for both approaches, as was the magnitude of volume error. Partial-volume effects in the direction perpendicular to the transverse planes of reconstruction affected volume accuracy, however. Computed tomography numbers were reproduced accurately, but 4D images exhibited more variation in CT number than static CT images did. Characterization of such properties can be used to better understand and optimize the various parameters that affect 4D CT image quality.
authors: Departments of Radiation Physics, The University of Texas M.D. Anderson Cancer Center, Houston, Texas, U.S.A.
authors: George
authors: G
authors: Starkschall
authors: Departments of Radiation Physics, The University of Texas M.D. Anderson Cancer Center, Houston, Texas, U.S.A.
authors: Neil
authors: N
authors: Desai
authors: Departments of Radiation Physics, The University of Texas M.D. Anderson Cancer Center, Houston, Texas, U.S.A.
authors: Peter
authors: P
authors: Balter
authors: Departments of Radiation Physics, The University of Texas M.D. Anderson Cancer Center, Houston, Texas, U.S.A.
authors: Karl
authors: K
authors: Prado
authors: Departments of Radiation Physics, The University of Texas M.D. Anderson Cancer Center, Houston, Texas, U.S.A.
authors: Dershan
authors: D
authors: Luo
authors: Departments of Imaging Physics, The University of Texas M.D. Anderson Cancer Center, Houston, Texas, U.S.A.
authors: Dianna
authors: D
authors: Cody
authors: Departments of Imaging Physics, The University of Texas M.D. Anderson Cancer Center, Houston, Texas, U.S.A.
authors: Tinsu
authors: T
authors: Pan
mesh_terms: D016477:Artifacts; D021621:Imaging, Three-Dimensional / Q000295:instrumentation / Q000379:methods*; D009068:Movement; D019047:Phantoms, Imaging; D011785:Quality Assurance, Health Care / Q000379:methods*; D011856:Radiographic Image Enhancement / Q000295:instrumentation / Q000379:methods*; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000295:instrumentation / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013382:Subtraction Technique; D014057:Tomography, X-Ray Computed / Q000295:instrumentation* / Q000379:methods*
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