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SU‐E‐I‐12: Characterization of Edge Effects in a Commercial Low‐Dose Image Processing System
Author(s) -
Marsh R,
Silosky M
Publication year - 2014
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.4887960
Subject(s) - clarity , kerma , image quality , fluoroscopy , image processing , optics , computer vision , computer science , artificial intelligence , nuclear medicine , medicine , dosimetry , physics , image (mathematics) , radiology , biochemistry , chemistry
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.