Existing VOIs can be used as boundary restrictions when generating certain types of VOIs. Iso-contouring within a VOI is an example described above. Five other approaches are available via the selection illustrated below.
A sub-VOI is generated by first selecting the bounding VOI in the VOIs list, and thereafter one of the tools in the list. They will generate a new VOI with a name containing the bounding VOI name in brackets.
The name in brackets works as a grouping criterion on the Group panel.