1 research outputs found
Multi-materials beam hardening artifacts correction for computed tomography (CT) based on X-ray spectrum estimation
Due to the energy-dependent nature of the attenuation coefficient and the
polychromaticity of the X-ray source, beam hardening effect occurs when X-ray
photons penetrate through an object, causing a nonlinear projection data. When
a linear reconstruction algorithm, such as filtered backprojection, is applied
to reconstruct the projection data, beam hardening artifacts which show as
cupping and streaks are present in the CT image. The aim of this study was to
develop a fast and accurate beam hardening correction method which can deal
with beam hardening artifacts induced by multi-materials objects. Based on
spectrum estimation, the nonlinear attenuation process of the X-ray projection
was modeled by reprojecting a template image with the estimated polychromatic
spectrum. The template images were obtained by segmenting the uncorrected into
different components using a simple segmentation algorithm. Numerical
simulations, experimental phantom data and animal data which were acquired on a
modern diagnostic CT scanner (Discovery CT750 HD, GE Healthcare, WI, USA) and a
modern C-Arm CT scanner (Artis Zee, Siemens Healthcare, Forchheim, Germany),
respectively, were used to evaluate the proposed method. The results show the
proposed method significantly reduced both cupping and streak artifacts, and
successfully recovered the Hounsfield Units (HU) accuracy.Comment: 10 pages, 12 figure