Statistical Image Reconstruction with Beam-Hardening compensation for X-ray CT by a calibration step (2DIterBH) Articles uri icon

publication date

  • June 2024

start page

  • 5204

end page

  • 5213

issue

  • 8

volume

  • 51

International Standard Serial Number (ISSN)

  • 0094-2405

Electronic International Standard Serial Number (EISSN)

  • 2473-4209

abstract

  • Background
    The beam-hardening effect due to the polychromatic nature of the X-ray spectra results in two main artifacts in CT images: cupping in homogeneous areas and dark bands between dense parts in heterogeneous samples. Post-processing methods have been proposed in the literature to compensate for these artifacts, but these methods may introduce additional noise in low-dose acquisitions. Iterative methods are an alternative to compensate noise and beam-hardening artifacts simultaneously. However, they usually rely on the knowledge of the spectrum or the selection of empirical parameters.

    Purpose
    We propose an iterative reconstruction method with beam hardening compensation for small animal scanners that is robust against low-dose acquisitions and that does not require knowledge of the spectrum, overcoming the limitations of current beam-hardening correction algorithms.

    Methods
    The proposed method includes an empirical characterization of the beam-hardening function based on a simple phantom in a polychromatic statistical reconstruction method. Evaluation was carried out on simulated data with different noise levels and step angles and on limited-view rodent data acquired with the ARGUS/CT system.

    Results
    Results in small animal studies showed a proper correction of the beam-hardening artifacts in the whole sample, independently of the quantity of bone present on each slice. The proposed approach also reduced noise in the low-dose acquisitions and reduced streaks in the limited-view acquisitions.

    Conclusions
    Using an empirical model for the beam-hardening effect, obtained through calibration, in an iterative reconstruction method enables a robust correction of beam-hardening artifacts in low-dose small animal studies independently of the bone distribution.

subjects

  • Biology and Biomedicine

keywords

  • artifacts; beam hardening; ct; penalized-likelihood; polychromatic; streaks