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SU-E-I-12: Characterization of Edge Effects in a Commercial Low-Dose Image Processing System

Journal Article · · Medical Physics
DOI:https://doi.org/10.1118/1.4887960· OSTI ID:22325134
;  [1]
  1. University of Colorado School of Medicine, Aurora, CO (United States)
Purpose: Minimizing radiation dose while preserving image quality is critical in fluoroscopic imaging. One recent development is a noise reduction system (Allura Clarity) offered by Philips. Others have reported approximately 50% reduction in air kerma when using Clarity. These studies, however, provide only a cursory look at how the Clarity system affects image quality. The purpose of this work was to evaluate the effect of Clarity on the appearance of high-frequency image information. Methods: A lead attenuator with a smooth edge was imaged on two Philips Allura FD20 detectors: one with Clarity and one without. The edge was positioned in the center of the field of view and images were obtained under the following conditions: 40cm and 11cm fields of view, single shot and continuous fluoroscopy modes, and using abdomen and cardiac protocols, for a total of sixteen imaging conditions. Profiles were drawn perpendicular to the edge across 80% of its length, averaged to reduce noise, normalized to the maximum pixel value, and plotted as a function of distance. Results: For all single-shot acquisitions and most fluoroscopic images, overshoot of the edge was observed. This effect was more substantial for single-shot acquisitions (∼20%) than for fluoroscopic images (∼50%). For fluoroscopic acquisition, the overshoot decayed more quickly with the Clarity system. However, the system with Clarity introduced a ringing effect for both single-shot and fluoroscopic images that is not present on the non-Clarity system. Conclusion: Previous reports have demonstrated a substantial dose reduction when using Clarity but the impact this has on image appearance has not been characterized. One demonstrated difference is the change in appearance of high-frequency image information. It remains to be determined whether this effect may impact clinical images adversely.
OSTI ID:
22325134
Journal Information:
Medical Physics, Journal Name: Medical Physics Journal Issue: 6 Vol. 41; ISSN 0094-2405; ISSN MPHYA6
Country of Publication:
United States
Language:
English