The density-map reconstruction of a radiological contrast medium is affected by noise arising from the background lack of homogeneity (the so-called “projection error”) if images of the medium are collected starting from quasi-monochromatic X-ray beams. This noise, especially for a dual-energy reconstruction algorithm, becomes more significant than the statistical fluctuations of the photon-transmitted flux, dramatically reducing the accuracy and the sensitivity of the reconstruction. In this work, we investigate the efficacy of the triple-energy technique, which is based on the simultaneous acquisition of three monochromatic images of the same target injected with contrast medium. A theoretical analysis allows to estimate the sensitivity and the accuracy of the reconstructed density map compared with the dual-energy one (i.e., the density map reconstructed acquiring only two monochromatic images). To validate the theory, a set of experimental measurements was performed: results show that triple energy drastically reduces the projection errors (from 10 to 60 times smaller than the dual-energy one), making it negligible with respect to the statistical noise.
Titolo: | A method to remove the projection error in triple-energy radiography with contrast medium |
Autore/i: | BALDAZZI, GIUSEPPE; LANCONELLI, NICO; MASETTI, SIMONE; M. Fiaschetti; M. Maccagnani; ROMA, LAURA; ROSSI, PIER LUCA; LEVI, GIUSEPPE; C. Sbarra |
Autore/i Unibo: | |
Anno: | 2009 |
Rivista: | |
Digital Object Identifier (DOI): | http://dx.doi.org/10.1016/j.nima.2009.05.079 |
Abstract: | The density-map reconstruction of a radiological contrast medium is affected by noise arising from the background lack of homogeneity (the so-called “projection error”) if images of the medium are collected starting from quasi-monochromatic X-ray beams. This noise, especially for a dual-energy reconstruction algorithm, becomes more significant than the statistical fluctuations of the photon-transmitted flux, dramatically reducing the accuracy and the sensitivity of the reconstruction. In this work, we investigate the efficacy of the triple-energy technique, which is based on the simultaneous acquisition of three monochromatic images of the same target injected with contrast medium. A theoretical analysis allows to estimate the sensitivity and the accuracy of the reconstructed density map compared with the dual-energy one (i.e., the density map reconstructed acquiring only two monochromatic images). To validate the theory, a set of experimental measurements was performed: results show that triple energy drastically reduces the projection errors (from 10 to 60 times smaller than the dual-energy one), making it negligible with respect to the statistical noise. |
Data prodotto definitivo in UGOV: | 2009-11-03 19:55:14 |
Appare nelle tipologie: | 1.01 Articolo in rivista |