
Proceedings Paper
Scatter correction for x-ray conebeam CT using one-dimensional primary modulationFormat | Member Price | Non-Member Price |
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Paper Abstract
Recently, we developed an efficient scatter correction method for
x-ray imaging using primary modulation.
A two-dimensional (2D) primary modulator with spatially variant attenuating materials is inserted between
the x-ray source and the object to separate primary and scatter signals in the Fourier domain. Due to the
high modulation frequency in both directions, the 2D primary modulator has a strong scatter correction
capability for objects with arbitrary geometries. However, signal processing on the modulated projection
data requires knowledge of the modulator position and attenuation. In practical systems, mainly due to
system gantry vibration, beam hardening effects and the
ramp-filtering in the reconstruction, the insertion
of the 2D primary modulator results in artifacts such as rings in the CT images, if no post-processing is
applied. In this work, we eliminate the source of artifacts in the primary modulation method by using a
one-dimensional (1D) modulator. The modulator is aligned parallel to the ramp-filtering direction to avoid
error magnification, while sufficient primary modulation is still achieved for scatter correction on a quasicylindrical
object, such as a human body. The scatter correction algorithm is also greatly simplified for
the convenience and stability in practical implementations. The method is evaluated on a clinical CBCT
system using the Catphan© 600 phantom. The result shows effective scatter suppression without introducing
additional artifacts. In the selected regions of interest, the reconstruction error is reduced from 187.2HU to
10.0HU if the proposed method is used.
Paper Details
Date Published: 12 March 2009
PDF: 8 pages
Proc. SPIE 7258, Medical Imaging 2009: Physics of Medical Imaging, 725820 (12 March 2009); doi: 10.1117/12.813849
Published in SPIE Proceedings Vol. 7258:
Medical Imaging 2009: Physics of Medical Imaging
Ehsan Samei; Jiang Hsieh, Editor(s)
PDF: 8 pages
Proc. SPIE 7258, Medical Imaging 2009: Physics of Medical Imaging, 725820 (12 March 2009); doi: 10.1117/12.813849
Show Author Affiliations
Published in SPIE Proceedings Vol. 7258:
Medical Imaging 2009: Physics of Medical Imaging
Ehsan Samei; Jiang Hsieh, Editor(s)
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