Room: ePoster Forums
Purpose: A vendorâ€™s current digital radiography detector was announced to be significantly more efficient than the past generation, and our institutionâ€™s technologists lowered the dose from a target EI of 220 to 140. We desired to measure how image quality was affected by using the new detector and lower dose target.
Methods: The experiment used a Siemens Multix x-ray room and two digital detectors (â€œoldâ€? and â€œnewâ€?). Three QA phantoms were used: ACR radiography accreditation image quality phantom, Huttner phantom, and an aluminum contrast-recovery plate. They were placed directly on the detector/grid with 2â€? â€“ 8â€? Lucite. The kVp corresponded to the Lucite thickness, and the mAs was selected so that the EI would approximate either 220 or 140. Images were acquired for both detectors at both EI values for each phantom. Images were processed using ImageJ, de-identified, ordered pseudo-randomly, and scored by seven physicists and technologists in terms of phantom detail visibility. The scores for the â€œoldâ€? and â€œnewâ€? detectors were compared at the baseline dose and the lower dose.
Results: The score of the reader furthest from the mean was dropped and then the detector scores were classified as â€œsimilarâ€?, â€œbetterâ€?, or â€œworseâ€? based on a half step (0.5) in score. Of 52 image quality elements, the new detector at baseline dose rated â€œbetterâ€? 13 times, â€œworseâ€? twice and â€œsimilarâ€? 37 times; at the lower dose: â€œbetterâ€? 3 times, â€œworseâ€? 10 times and â€œsimilarâ€? 39 times.
Conclusion: The anecdotal evidence at our institution was that the new detector has improved image quality and can be used at 40% lower dose than the baseline. This testing has shown that the image quality was improved at the baseline dose and slightly worse at 40% lower dose. Our institution can now make an informed decision on cost-vs.-benefit of the new detector.