Aviv Hirschenbein MD, Presenter: Medical Director, CMT Medical Technologies Ltd, Israel

Doron Fischer BSc, MD, Abstract Co-Author: Nothing to Disclose

Jacob Sosna MD, Abstract Co-Author: Research grant, Koninklijke Philips Electronics NV

Haim Greenwald, Abstract Co-Author: Nothing to Disclose

Yossi Katzav, Abstract Co-Author: Nothing to Disclose

S. Nahum Goldberg MD, Abstract Co-Author: Medical Advisory Board, Tyco Healthcare (Valleylab), Boulder, CO Research support, Tyco Healthcare (Valleylab), Boulder, CO Research support, RITA Medical Systems, Inc, Freemont, CA

Dual energy imaging is traditionally performed using Digital radiography(DR)or Computed radiography(CR). While DR has a better quantum detective efficiency (QDE) and automatic exposure control (AEC) for optimization of exposure dose, it uses two exposures at different times and parameters causing a higher exposure dose and possible artifacts. CR is performed using a single exposure, but has a low QDE for high-energy x-ray photons creating a need for a higher doses and does not have AEC for optimization of the dose. Our purpose was to evaluate a new method that combines using a CR cassette in front of the DR flat panel to accentuate the benefits from both methods

CR cassettes were placed in front of the DR panel and 0.6 mm of copper filter in between (SynCDR prototype, CMT, Yokneam, Israel). We used a one shot exposure and AEC for optimization of image quality. The images were registered and subtracted using a novel algorithm to overcome differences in magnification scale and resolution. We used an anthropomorphic phantom of a chest with a small coin of aluminum to simulate a calcified lung nodule. We performed 15 combined images placing the coin at different areas and a different thickness of the chest phantom. The same procedure was repeated with DR only and CR only images. Three qualified radiologists evaluated and rated quality of the images on a scale of 1 to 5

The average score of all three groups was 3.7.The average score of the CR images group was 3.3.The average score of the DR images group was 3.5.The average score of the combined image group was 4.2 and significantly better than the others groups (p=0.001). There was no significant difference between the CR and DR groups

Our result suggests that the use of combined DR and CR for one-shot dual-energy is feasible and may have a benefit over conventional DR and CR dual energy methods

The ability to combine a CR cassette in front of the DR flat panel may have a synergistic effect combing benefits of both techniques

Hirschenbein, A, Fischer, D, Sosna, J, Greenwald, H, Katzav, Y, Goldberg, S, Synergized Computed Radiography and Digital Radiography (SynCDR): A New Method for Dual Energy Substraction Images—A Feasibility Study.  Radiological Society of North America 2007 Scientific Assembly and Annual Meeting, November 25 - November 30, 2007 ,Chicago IL. http://archive.rsna.org/2007/5003076.html