GE Senographe DS Operator's Manual page 109

GE Healthcare
Revision 1
3-3 Graphics and measurements
These buttons allow you to add graphic and text annotations to the image, and perform measurements.
You can add several graphic annotations (line segments and ellipses) on the same image. Each annota-
tion is identified by a number, which is displayed next to it. The corresponding measurements, with the
same identification number, are displayed in the bottom right corner of the image.
Only the three most recent measurements are displayed. To recall an earlier measurement value on the
screen, click on the corresponding line segment or ellipse.
Segment
• Click the Segment button to place on the image a line segment that you can use to measure
the distance between two points.
- The squares at each end of the segment are called handles.
- Press and drag on either of the handles to move the corresponding end of the segment to the
desired position. The size and angle of the segment follow the movement of the handles.
- To move the whole segment, select the segment by clicking on any point along the line (except
the handles) and drag the segment to the desired position.
The length of the segment (in millimeters) and the angle between the segment and the vertical (in
degrees) are displayed in the bottom right corner of the image.
Ellipse
• Click the Ellipse button to place on the image an ellipse, that you can use to highlight an
area of interest, or to measure the area delimited by the ellipse.
- The ellipse is displayed with four handles around it, four tick marks on the ellipse itself,
and a cross mark in the center.
- To change the size and shape of the ellipse, press and drag on the handles.
- To rotate the ellipse around its center, press and drag on any of the tick marks.
- To move the actual ellipse, press anywhere on the ellipse (except for the tick marks), or on the
center cross, and drag the ellipse to its desired position.
The area of the ellipse (in square millimeters), and the mean and standard deviation of the pixel val-
ues within the ellipse, are displayed in the bottom right corner of the image.
CAUTION
All measurement calculations for graphical annotations (length, surface area, etc.) are
made in a reference plane which is 2 cm above the breast contact surface. These values
therefore do not correspond to the true size of a pathological feature unless it is situated
in the reference plane.
Pixel gray levels in raw images are linearly proportional to the X-ray dose received by the
detector. Gray levels in processed images are proportional to the logarithm of the dose.
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Senographe DS Acquisition System
Operator Manual 5307907-3-S-1EN
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Chapter 11