Dual-energy cardiac imaging: an image quality and dose comparison for a flat-panel detector and x-ray image intensifier.

This study presents a comparison of dual-energy imaging with an x-ray image intensifier and flat-panel detector for cardiac imaging. It also investigates if the wide dynamic range of the flat-panel detector can improve dual-energy image quality while reducing patient dose. Experimental contrast-to-noise (CNR) measurements were carried out in addition to simulation studies. Patient entrance exposure and system tube loading were also recorded. The studied contrast objects were calcium and iodine. System performance was quantified with a figure-of-merit (FOM) defined as the image CNR(2) over patient entrance exposure. The range of thickness studied was from 10 to 30 cm of Lucite (PMMA). Detector dose was initially set to 140 nGy (16 microR)/frame. The high-energy 120 kVp beam was filtered by an additional 0.8 mm silver filter. Keeping the same filament current, the kVp for the low-energy beam was adjusted as a function of thickness until 140 nGy was achieved. System performance was found to be similar for both systems, with the x-ray image intensifier performing better at lower thicknesses and the flat-panel detector performing better at higher thicknesses. This requirement of fixed detector entrance exposure was then relaxed and the kVp for the low-energy beam was allowed to vary while the mAs of the x-ray tube remained fixed to study changes in dual-energy image quality, patient dose and FOM with the flat-panel detector. It was found that as the kVp for the low-energy beam was reduced, system performance would rise until reaching a maximum while simultaneously lowering patient exposure. Suggested recommendations for optimal dual-energy imaging implementation are also provided.

[1]  E. Gronenschild,et al.  The accuracy and reproducibility of a global method to correct for geometric image distortion in the x-ray imaging chain. , 1997, Medical physics.

[2]  A. Macovski,et al.  Generalized image combinations in dual KVP digital radiography. , 1981, Medical physics.

[3]  M J Yaffe,et al.  Theoretical optimization of dual-energy x-ray imaging with application to mammography. , 1985, Medical physics.

[4]  J M Boone,et al.  Comparison of x-ray cross sections for diagnostic and therapeutic medical physics. , 1996, Medical physics.

[5]  Michael S. Van Lysel.  Optimization of beam parameters for dual-energy digital subtraction angiography. , 1994 .

[6]  C A Mistretta,et al.  Quantification techniques for dual-energy cardiac imaging. , 1989, Medical physics.

[7]  J A Seibert,et al.  Removal of image intensifier veiling glare by mathematical deconvolution techniques. , 1985, Medical physics.

[8]  J A Seibert,et al.  Characterization of the veiling glare PSF in x-ray image intensified fluoroscopy. , 1984, Medical physics.

[9]  Martin Spahn,et al.  Flat detectors and their clinical applications , 2005, European Radiology.

[10]  A Fenster,et al.  Dual-energy mammography: initial experimental results. , 1985, Medical physics.

[11]  R E Alvarez.  Active energy selective image detector for dual-energy computed radiography. , 1996, Medical physics.

[12]  C A Mistretta,et al.  A correlated noise reduction algorithm for dual-energy digital subtraction angiography. , 1989, Medical physics.

[13]  M. S. Lysel.  Limitations of the lead oxide vidicon for dual-energy digital subtraction angiography , 1991 .

[14]  W. Kalender,et al.  An algorithm for noise suppression in dual energy CT material density images. , 1988, IEEE transactions on medical imaging.

[15]  G T Barnes,et al.  Detector for dual-energy digital radiography. , 1985, Radiology.

[16]  Mahadevappa Mahesh,et al.  Fluoroscopy: patient radiation exposure issues. , 2001, Radiographics : a review publication of the Radiological Society of North America, Inc.

[17]  D. Chakraborty.  Image intensifier distortion correction. , 1987, Medical physics.

[18]  James T Dobbins,et al.  Quantitative , 2020, Psychology through Critical Auto-Ethnography.

[19]  J. Boone,et al.  An accurate method for computer-generating tungsten anode x-ray spectra from 30 to 140 kV. , 1997, Medical physics.

[20]  Van Lysel Ms.  The AAPM/RSNA physics tutorial for residents: fluoroscopy: optical coupling and the video system. , 2000 .

[21]  James T. Dobbins,et al.  Recent progress in noise reduction and scatter correction in dual-energy imaging , 1995, Medical Imaging.