6.6. Union, subtraction and intersection of structures

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Functionality is available in the Pro edition
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This tool allows you to create the unions, intersections and subtractions of structures. The button will look different depending on which instrument was last used:


	Union segmented structures (selected by default)

	Subtract segmented structures

	Intersect segmented structures

To use a tool that is already selected, simply click on the left side of the tool buttons. To select another tool, click on the arrow on the right of the button and select an appropriate item from the list.

6.6.1 Union

The unification of structures is the addition of one structure to another. The added structure remains unchanged. To unite structures:

Select the current structure on the Segmented Structure Panel (e.g., the left lung).

Click on the Union segmented structures button. The dialog box shown in Fig. 6.10 will be displayed.
Select the structure to merge with the current one (e.g., the right lung). If you want to make the right lung invisible after the merging process, check the Hide selected segmented structure box. To make it visible later, check the Visible box for this structure.
To merge, click OK, to cancel, click Cancel.

After the merging process, the original structure will consist of the tissues contained in both structures.

Figure 6.10: Union

6.6.2 Subtraction

The subtraction of structures is the removal of the original tissue structure present in another structure. To subtract structures:

Select the current structure on the Segmented Structure Panel (e.g., the lungs).

Click on the Subtract segmented structures button. The dialog box, similar to the one shown in Fig. 6.10, will be displayed.
Select the structure you want to subtract from the current one (e.g., the rigth lung). If you want to make the right lung invisible after subtraction, check the Hide selected segmented structure box. To make it visible later, check the Visible box for this structure.
To subtract, click OK, to cancel, click Cancel.

After subtraction, the right lung tissue will be removed from the original structure (Lungs).

6.6.3 Intersection

The intersection of structures is the removal of all tissues from one structure, except those present in both structures. To intersect structures:

Select the current structure on the Segmented Structure Panel.

Click on the Intersect segmented structures button. The dialog box, similar to the one shown in Fig. 6.10, will be displayed.
Select the structure you want to intersect with the current one. If you want to make the second structure invisible after intersection, check the Hide selected segmented structure box. To make it visible later, check the Visible box for this structure.
To intersect, click OK, to cancel, click Cancel.

After intersection, the current structure will consist of the tissues contained in both structures.