Eigenvector decomposition of full-spectrum x-ray computed tomography

Abstract

Energy-discriminated x-ray computed tomography (CT) data were projected onto a set of basis functions to suppress the noise in filtered back-projection (FBP) reconstructions. The x-ray CT data were acquired using a novel x-ray system which incorporated a single-pixel photon-counting x-ray detector to measure the x-ray spectrum for each projection ray. A matrix of the spectral response of different materials was decomposed using eigenvalue decomposition to form the basis functions. Projection of FBP onto basis functions created a de facto image segmentation of multiple contrast agents. Final reconstructions showed significant noise suppression while preserving important energy-axis data. The noise suppression was demonstrated by a marked improvement in the signal-to-noise ratio (SNR) along the energy axis for multiple regions of interest in the reconstructed images. Basis functions used on a more coarsely sampled energy axis still showed an improved SNR. We conclude that the noise-resolution trade off along the energy axis was significantly improved using the eigenvalue decomposition basis functions.

2013 Atomic spectrometry update—A review of advances in X-ray fluorescence spectrometry

“…Non-invasive, in vivo measurements of Pb in bone using 109 Cdbased K-shell XRF spectrometry is widely implemented in epidemiological studies. Bellis et al 367 conducted the rst and very interesting interlaboratory study of the use of K-shell XRF for the analysis of nine goat tibiae in which the mean Pb value ranged from 4.0 mg g À1 to 55.3 mg g À1 bone mineral and validated these concentrations by ICP-MS aer nitric acid digestion.…”