GE Healthcare
Senographe DS Acquisition System
Revision 1
Operator Manual 5307907-3-S-1EN
Image Acquisition Procedure
12-imgac.fm
Page no. 135
Chapter 12
10
Check View Names
The user can check the image for correct view name and laterality, and change them if necessary. Refer
to Chapter
, section
3-5 change view name on page 112
.
11
Quality Check (With or Without RRA)
The operator must examine each image and determine if its quality is satisfactory and qualify it, if neces-
sary, using the Quality Check feature. This may be done with the Repeat and Reject Analysis (RRA)
function either enabled or disabled.
Refer to:
•
8-3 Medical Application preferences on page 75
, subheading
, that explains the aim of this feature.
•
, that explains how to use this feature.
12
Processing
Images received from the Digital Detector are displayed on the LCD monitor as
raw
images immediately
after acquisition. Raw images are low contrast. After acquisition, a number of calculations are applied to
the image to create the
processed
image, which replaces the raw image on the screen.
Note that both processed and raw images are saved. The raw images are saved in the DICOM MG "for
processing" format so that processing can be carried out later if required, perhaps using a hospital-spe-
cific algorithm. The processed images are saved in the DICOM MG "for presentation" format, ready for
review.
The main calculations that can be applied to create the processed image are:
•
Collimator Detection. This applies a black mask around the useful image area, covering areas which
would otherwise be white. It allows more comfortable viewing.
•
Pseudo-log Transformation. This facilitates the manipulation of brightness and contrast during the
review. After the transformation the image dynamic range is reduced to 12 bits, without loss of clinical
information.
•
Depending on user choice in medical preferences (see Chapter
Application preferences on page 75
), either Thickness Equalization or Premium View will be applied:
-
Thickness Equalization. Subcutaneous tissues can be difficult to see on the screen because of
monitor display limitations. This is corrected by applying a Thickness Equalization algorithm to
decrease the image dynamic range. Image information beyond a threshold level of gray, selected
to correspond to subcutaneous tissues, is modified for more visibility. The end result is clear visi-
bility of the medical information in all regions of the breast. When this algorithm is used, the pro-
cessing description applied is referred to as Proc 1.
The Thickness Equalization algorithm is not applied to the following images:
-
Magnified, Spot and Collimated views.
-
Images in which the breast tissue covers 100% of the digital detector panel area.
-
Images with certain combinations of manually selected parameters.
The processing description applied to these images, when the Thickness Equalization algo-
rithm is not used, is referred to as Proc 0.
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