Scientific publications

A new method to measure electron density and effective atomic number using dual-energy CT images

Jan 7, 2016 | Magazine: Physics in Medicine and Biology

Garcia LI (1), Azorin JF, Almansa JF.
(1) Department of Oncology, Clínica Universidad de Navarra, University of Navarra, Av Pio XII s/n, Pamplona, Navarre, Spain 

The purpose of this work is to present a new method to extract the electron density ([Formula: see text]) and the effective atomic number (Z eff) from dual-energy CT images, based on a Karhunen-Loeve expansion (KLE) of the atomic cross section per electron.

This method was used to calibrate a Siemens Definition CT using the CIRS phantom. The predicted electron density and effective atomic number using 80 kVp and 140 kVp were compared with a calibration phantom and an independent set of samples.

The mean absolute deviations between the theoretical and calculated values for all the samples were 1.7 %  ±  0.1 % for [Formula: see text] and 4.1 %  ±  0.3 % for Z eff.

Finally, these results were compared with other stoichiometric method. The application of the KLE to represent the atomic cross section per electron is a promising method for calculating [Formula: see text] and Z eff using dual-energy CT images.

CITATION  Phys Med Biol. 2016 Jan 7;61(1):265-79. doi: 10.1088/0031-9155/61/1/265