TY - JOUR
T1 - Quantitative assessment of four-dimensional computed tomography image acquisition quality
AU - Starkschall, George
AU - Desai, Neil
AU - Balter, Peter
AU - Prado, Karl
AU - Luo, Dershan
AU - Cody, Dianna
AU - Pan, Tinsu
PY - 2007
Y1 - 2007
N2 - 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.
AB - 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.
KW - 4D imaging
KW - Computed tomography
KW - Image assessment
KW - Organ motion
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U2 - 10.1120/jacmp.v8i3.2362
DO - 10.1120/jacmp.v8i3.2362
M3 - Article
C2 - 17712299
AN - SCOPUS:34548274489
SN - 1526-9914
VL - 8
SP - 1
EP - 20
JO - Journal of applied clinical medical physics
JF - Journal of applied clinical medical physics
IS - 3
ER -