Chapter 11: Image Viewer
5495975-1EN Rev.9
11-19
© 2013-2017 General Electric Company. All rights reserved.
Deviation Index (DI)
The direct connection between the level of detector exposure and optical density is well established in
film-screen radiography, but this is not the case in digital radiography because of automatic image pro-
cessing optimizing image looks. In order to provide detector entrance dose information, DEI feature is
provided to the users, displaying a way for customers to understand detector exposure level. For each
acquired image, the DEI provides 3 estimates values:
Deviation Index (DI): A unitless index that gives the user an indication of the exposure level of an
acquisition, relative to a target exposure level defined in the system.
Exposure Index (EI): A unitless value that estimates the detector exposure assuming that the x-ray
technique (e.g., kVp, Cu filtration) used is the same as that of the calibration technique.
Compensated Detector Exposure (CDExp): Estimate of exposure in µGy based on the actual x-ray tech-
nique (e.g., kVp, Cu filtration) used for the acquisition under simulated clinical condition.
In particular, DI provides a visual indicator to the user. The display method for DI, DI range, and Target
exposure can be configurable in the user preference. Refer to
Chapter 15: Preferences-DI (Deviation
for more information.
Look
Changes the processing look.
Looks are the way an image is processed to be viewed by a radiologist for
interpretation.
Looks are pre-defined combinations of brightness, contrast, edge enhancement,
and tissue equalization.
Factory Look descriptions:
Factory Look 1 – similar to analog film, low edge, no TE
Factory Look 2 – low CR look, low edge, moderate tissue contrast
Factory Look 3 – moderate CR look, low edge, TE
Factory Look 4 – highly digital look, high edge, high TE
Custom looks – The system allows you to build up to 5 custom looks in any com-
bination of parameters. Refer to
Chapter 15: Preferences-Image Processing
for more information on building custom looks.
[REPROCESS]
Applies the changes and re-processes the image.
Re-processing creates a new image in the series.
Note:
The button does not become enabled until the Look is selected.
[EDIT PROC]
Displays Image Processing Preference Editor screen that allows you to view the
Factory look settings or create custom looks.
Refer to
Chapter 15: Preferences-Image Processing (p. 15-49)
for more information
about building custom looks.
Table 11-6
Reprocessing tool descriptions
Function
Description
