"GPS" -- Position Marking V Nav
Position markers can be 'placed' on a stationary anatomical structure within the body and then tracked with the existing position sensing system. The marker position is projected onto the current Ultrasound image in a graphical way that indicates the relative position of the point compared to the image. GPS markers track a particular point in space.
Controls
Selecting the GPS tab switches trackball control to GPS markers with 2D Marker or 3D Marker activated.
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2D GPS Markers |
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GPS Markers track a particular point in space. As you adjust the probe/image position, the point is projected onto the current image. If the point intersects the current image, it is displayed as a green cross. As the point gets further away from the current image, the cross turns into a bigger and bigger square. The color of the square indicates the direction; red represents one direction and blue represents the other direction. |
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There are two types of GPS Markers: Point and Target. |
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A Point Marker assigns a number. Each point marker you set has a unique number. |
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A Target Marker only allows one target point. If you try to place another target marker, the target moves to the newly-indicated position. |
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To place a Target or Point Marker, use GPS Marker to specify Target or Point. Place the Windows Pointer in the location where you want to set the marker, then press the Set GPS Key. |
| 3D GPS Markers | ||||||
| Type of Markers | ||||||
| Ellipsoid | ||||||
| The user places one GPS Marker (Set GPS on the right trackball key) at one end of the desired long axis. The point is marked with a marker named LA that behaves like a point marker. The distance between this first long axis point and the current cursor position is displayed in the status bar to allow the user to mark an ellipsoid with a defined long axis length. The user then places a second GPS Marker (Set GPS on the right trackball key) at the other end of the desired long axis. The ellipsoid will be drawn and the long axis endpoints will be marked with crosses that will be displayed only if they are hit by the plane. | ||||||
| Spherical | ||||||
The user places the GPS Marker (Set GPS key on right trackball key) at the center point of the anatomical structure of interest. The center of the sphere is marked with a cross, that is only displayed if the plane hits the center.
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