5.7. Markers

A marker is a point, line or polygonal line in space, associated with a model. The DICOM Viewer allows you to display the length of the marker line and the polygonal marker line and the angles of the polygonal marker line.

The following tools are used to add markers: Marker, Line marker and Polygonal Line marker. To select one of these tools, click on the arrow on the right side of the tool selection button. The button will look different depending on the selected tool:

	Marker (selected by default)
	Line marker
	Polygonal Line marker

To add a marker as a point:

1. Activate the Marker tool by clicking the button on the toolbar.
2. Mark a place on an image by clicking the left mouse button. The marker will appear in all three windows.

After adding all the markers, deactivate the Marker tool.

To add a Line marker:

1. Activate the Line marker tool by clicking on the button on the toolbar.
2. Click the mouse button on the image to mark the first point.
3. Move the cursor over the screen to find the second point.
4. Click the mouse button to fix the current point. The line marker will appear in all three windows.
5. To cancel an incomplete addition, press Esc.

After adding all the line markers, deactivate the Line marker tool.

To add a Poilygonal Marker line:

1. Activate the Polygonal Line marker tool by clicking on the button on the toolbar.
2. Mark a point by clicking the mouse button.
3. Repeat the previous steps until the last but one point is fixed.
4. Fix the last point by double-clicking the mouse.
5. To cancel an incomplete addition, press Esc.

After adding all the polygonal line markers, deactivate the Polygonal Line marker tool.

To continue the polygonal marker line, move the cursor to the end point of the line, right-click and select the Continue line item.

This tool is also available from the image context menu and from the MPR main menu item. Activation is only possible with the left mouse button.

The following actions are available:

• Drag a point or line and polygonal line marker points. Locate the cursor on the marker or point so that it would look like , and drag it, holding down the left mouse button or the button to which this tool is assigned. The location of the marker will change accordingly in all the windows. The marker will be moved parallel to the displayed slice.
• Remove. Locate the cursor on the marker so that it would look like , right-click the mouse and select the Remove marker item.
• Remove all the markers. If you need to delete all the markers, locate the cursor on any marker so that it would look like this: , right-click the mouse and select the Remove all markers item or select the corresponding item from the Marker tool menu.

You can set the following properties:

• Text;
• Diameter or Line width;
• Color;
• Show length (for Line Markers);
• Show angle (for Polygonal Line Markers).

To set properties for previously added marker, locate the cursor over the marker, right-click and select the Set marker properties... item.

To set the default marker properties, click the arrow on the right side of the Marker button and select one of the Set Default Marker Properties..., Set default marker line properties... or Set default marker polygonal line properties... items.

If the marker is in or near the current slice, it is displayed as a circle; otherwise, it is displayed as a ring with a dot in the center. The further the marker slice is from the current slice, the darker the marker is.