The average workload per full-time equivalent (FTE) radiologist increased by 70% from1991-1992 to 2006-
2007. The increase is mainly due to the increase (34%) in the number of procedures, particularly in 3D imaging
procedures. New technologies such as picture archiving and communication systems (PACS) and embodied viewing
capability were accredited for an improved workflow environment leading to the increased productivity. However, the
need for further workflow improvement is still in demand as the number of procedures continues growing. Advanced and
streamlined viewing capability in PACS environment could potentially reduce the reading time, thus further increasing
the productivity. With the increasing number of 3D image procedures, radiographic procedures (excluding
mammography) have remained their critical roles in screening and diagnosis of various diseases. Although radiographic
procedures decreased in shares from 70% to 49.5%, the total number has remained the same from 1991-1992 to 2006-
2007. Inconsistency in image quality for radiographic images has been identified as an area of concern. It affects the
ability of clinicians to interpret images effectively and efficiently in areas where diagnosis, for example, in screening
mammography and portable chest radiography, requires a comparison of current images with priors. These priors can
potentially have different image quality. Variations in image acquisition techniques (x-ray exposure), patient and
apparatus positioning, and image processing are the factors attributed to the inconsistency in image quality. The
inconsistency in image quality, for example, in contrast may require manual image manipulation (i.e., windowing and
leveling) of images to accomplish an optimal comparison to detect the subtle changes. We developed a tone-scale image
rendering technique which improves the image consistency of chest images across time and modality. The rendering
controls both the global and local contrast for a consistent look. We expect the improvement could reduce the window
and level manipulation time required for an optimal comparison of priors and current images, thus improving both the
efficiency and effectiveness of image interpretation. This paper presents a technique for improving the consistency of
portable chest radiographic images. The technique is based on regions-of-interest (ROIs) to control both the local and
global contrast consistency.
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