Effect of x-ray energy dispersion in digital subtraction imaging at the iodine K-edge - A Monte Carlo study

F. Prino, C. Ceballos, A. Cabal, A. Sarnelli, M. Gambaccini, L. Ramello

Research output: Contribution to journalArticlepeer-review


The effect of the energy dispersion of a quasi-monochromatic x-ray beam on the performance of a dual-energy x-ray imaging system is studied by means of Monte Carlo simulations using MCNPX (Monte Carlo N-Particle eXtended) version 2.6.0. In particular, the case of subtraction imaging at the iodine K -edge, suitable for angiographic imaging application, is investigated. The average energies of the two beams bracketing the iodine K -edge are set to the values of 31.2 and 35.6 keV corresponding to the ones obtained with a compact source based on a conventional x-ray tube and a mosaic crystal monochromator. The energy dispersion of the two beams is varied between 0 and 10 keV of full width at half-maximum (FWHM). The signal and signal-to-noise ratio produced in the simulated images by iodine-filled cavities (simulating patient vessels) drilled in a PMMA phantom are studied as a function of the x-ray energy dispersion. The obtained results show that, for the considered energy separation of 4.4 keV, no dramatic deterioration of the image quality is observed with increasing x-ray energy dispersion up to a FWHM of about 2.35 keV. The case of different beam energies is also investigated by means of fast simulations of the phantom absorption.

Original languageEnglish
Pages (from-to)13-24
Number of pages12
JournalMedical Physics
Issue number1
Publication statusPublished - 2008


  • Dual-energy x-ray imaging
  • MCNP simulations
  • Quasi-monochromatic x-ray beams

ASJC Scopus subject areas

  • Biophysics


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