VOI Contour Generation Modes
There are several methods for generating contours:
There is a toolbar in the VOI interface which collects the different VOI editing modes. Note that the arrangement can be horizontal as illustrated below, or vertical, depending on the tool configuration. The toolbar can also be detached for placing it at a convenient location on the screen.
Contour Outlining Process
After creation with New VOI, a VOI is ready for the definition of a single contour per slice. Once a contour has been created in a slice, contour drawing is no more active. For adding another contour definition in the same slice, the user has to activate the New Contour button first.
During contour outlining or editing, it is important that the right VOI/contour is selected. A VOI can be selected by clicking at the entry in the VOIs list. If contours have already been outlined, the display will position on a slice with a contour of the selected VOI. Alternatively, a VOI can be selected by directly clicking at a contour vertex in the image.
It is recommended to complete the definitions of one VOI before the next is created. To this end, the user should work through the slices containing the object: In each slice outline the required contour(s) and then step to the next slice using the mouse wheel. Alternatively, if the contours are similar in neighboring slices, the contour(s) can be propagated to the next slice and then adjusted.
VOI definition is a tedious task, and many situations may occur where the user would like to undo a change. To this end an Undo function for most manipulations of contour VOIs available on a separate taskbar.
The arrow to the left allows undoing operations (goes back through history), while the button to the right allows redoing undone operations (goes forward through history).
Note: The Undo function is not applicable to changes to the image information itself.
Browsing the image in the orthogonal layout involves clicking into the image. If some VOI functionality is enabled such clicks may introduce unwanted changes to the VOI definitions. To avoid such effects, it is advised to select the Neutral Mode with the . Note that while working in a VOI editing mode, the VOI functionality can be disabled by holding down CTRL+SHIFT during clicking.