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Title: Metal artifact reduction by filter-based dual-energy cone-beam computed tomography on a bench-top micro-CBCT system: concept and demonstration
Authors: Iramina, Hiraku  kyouindb  KAKEN_id  orcid (unconfirmed)
Hamaguchi, Takumi
Nakamura, Mitsuhiro  kyouindb  KAKEN_id
Mizowaki, Takashi  kyouindb  KAKEN_id  orcid (unconfirmed)
Kanno, Ikuo  kyouindb  KAKEN_id
Author's alias: 伊良皆, 拓
濱口, 拓
中村, 光宏
溝脇, 尚志
神野, 郁夫
Issue Date: Jul-2018
Publisher: Oxford University Press (OUP)
Journal title: Journal of radiation research
Volume: 59
Issue: 4
Start page: 511
End page: 520
Abstract: We evaluated two dual-energy cone-beam computed tomography (DE-CBCT) methodologies for a bench-top micro-CBCT system to reduce metal artifacts on reconstructed images. Two filter-based DE-CBCT methodologies were tested: (i) alternative spectral switching and (ii) simultaneous beam splitting. We employed filters of 0.6-mm-thick tin and 0.1-mm-thick tungsten to generate high- and low-energy spectra from 120 kVp X-rays, respectively. The spectral switching method was imitated by two half scans with different filters (pseudo-switching). Filters were placed and between the X-ray tube and a phantom (‘1-u, ’ ‘2-u’), a phantom and a flat panel detector (‘1-d, ’ ‘2-d’), and compared with (iii) two half scans at 80 and 140 kVp [pseudo-(80, 140)]. For the splitting method, two half-width filters were aligned along a rotating axis. Projections were separated into halves and merged with corresponding areas of opposed projections after one full rotation. A solid 30-mm-diameter acrylic phantom and an acrylic phantom with four 5-mm-diameter titanium rods were used. DE images were generated by weighted summation of the high- and low-energy images. The blending factor was changed from 0 to +5 in increments of 0.01. Relative errors (REs) of the linear attenuation coefficients of the two phantoms and the contrast-to-noise ratios (CNRs) between the titanium and acrylic regions were compared. All methods showed zero REs except for the method (2-d). CNRs for pseudo-switching with upstream placement were 1.4-fold larger than CNRs for the pseudo-(80, 140) method. CNRs for the downstream placements were small. It was concluded that the pseudo-switching method with upstream placement is appropriate for reducing metal artifacts.
Rights: © The Author(s) 2018. Published by Oxford University Press on behalf of The Japan Radiation Research Society and Japanese Society for Radiation Oncology. This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (, which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited. For commercial re-use, please contact
DOI(Published Version): 10.1093/jrr/rry034
PubMed ID: 29718315
Appears in Collections:Journal Articles

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