X-ray tube potential, filtration, and detector considerations in dual-energy chest radiography

Academic Article

Abstract

  • The effect of x-ray tube potential and prepatient and interdetector filtration in single exposure dual energy chest imaging has been studied employing a carefully benchmarked model. The analysis utilized published methodology. Noise in simulated lung and mediastinum fields of the aluminum (bone) and Lucite (soft tissue) images were studied at fixed entrance skin exposure (ESE) for commonly employed sandwich detector and sandwich imaging plate configurations. Our results indicate noise in the lung increases slowly with tube potential above 120 kVp, while noise in the mediastinum decreases rapidly. Also, at high tube potential (>120 kVp) adding moderate amounts of prepatient A-edge filtration (=*100 mg/cm2) while optimizing imaging conditions for the lung tends to decrease noise in the lungs by 30% while increasing noise in the mediastinum by a similar amount. Without A-edge prepatient filtration, noise in the lung is minimized with Cu interdetector filter weights near 400 mg/cm2. In the mediastinum noise is minimized with heavier interdetector filter and prepatient A-edge filter weights. Prepatient A-edge filter weights that minimize image noise in either field can increase the tube loading by factors ranging from 10 to 1010. Systems designed with sandwich detectors using commercially available phosphors and coating weights can produce contrast-to-noise ratios (CNRs) as high as 50% of the. theoretical limit (defined as an optimized system with a totally absorbing rear detector). © 1994, American Association of Physicists in Medicine. All rights reserved.
  • Published In

  • Medical Physics  Journal
  • Digital Object Identifier (doi)

    Author List

  • Gauntt DM; Barnes GT
  • Start Page

  • 203
  • End Page

  • 218
  • Volume

  • 21
  • Issue

  • 2