Selenia User Guide
Appendix A—System Specifications
MAN-03270 Revision 003 123
A.8 Tissue Exposure Control (TEC) Mode
The Breast Density Default Setting
Selectable via the Generator default screen on the Acquisition
Workstation. Breast density defaults to the default setting at the
beginning of each new study and when the exposure mode is
first changed to TEC.
Update rate once every 2 seconds maximum
Mammography Unit Status Polling
Between image capture cycles, Acquisition Workstation
requests and displays current technique at a rate not slower
than once every 2 seconds. In TEC mode, the rate increases to
no slower than once per second, but not faster than once per
0.75 seconds. System response time for a single Generator
Technique command is 1 second or less.
A.9 Automatic Exposure Control (AEC)
Positionable in seven locations, centered laterally in the image
receptor support device. Position #1 is located 1 cm from the
chest wall. Positions are spaced in 1.7 cm increments.
The AEC region can be selected automatically by processing the
pre-exposure image data to find the corresponding dense
portion of the breast.
When the AEC region auto-selection is enabled, the detector
area that is scanned is dependent on the default x-ray
collimation that is linked to the compression paddle ID
of collimation by the operator is ignored for AEC region
auto-selection.
LEDs for each AEC sensor position on the compression gantry
indicate the selected position. The selected AEC region can be
viewed after selecting the check box.
The size and available position of the manual AEC regions are
indicated at the x-ray input surface of the compression paddle.
The filter and kV are selected using the recommended table
based exposure technique based on compressed breast thickness.
The exposure is terminated at an mAs value as determined by
the AEC system to yield a pixel count to which the unit has been
calibrated.
The Filter is not selectable. The filter defaults to Mo if the
system is configured with Moly Tube. The filter defaults to Rh
if the system is configured with a Tungsten Tube. Starting kV
is determined by the Gantry. mAs is determined by the Digital
Detector.
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