Once the Directive has been completed the next block will be Snapshot. The Snapshot contains a single CT image set and all contour variants (targets and organs at risk) associated with these images.

• Snapshot: captures the state (anatomy) of a patient at a certain point in time. Each snapshot contains a single Image Set (typically CT) and all contour (structure) variants associated with these images. Each unique Image Set imported into the patient should produce a new Snapshot. Each unique structure set imported into the snapshot should produce new contour variants for each unique contour. Each contour may have only a single “active” variant and the plan will automatically update based on the selection of the active variant.
• Variant: A specific model of a target, OAR, or other structure. A physician may provide an initial target contour and a treatment plan generated using this information. The physician may later (using the same CT image set) provide a revised target contour. Rather than import this revision as a new structure or override the original, you may specify this new contour as a variant of the original. Each contour may have only a single “active” variant and the plan will automatically update based on the selection of the active variant.

Within Astroid the planner has the ability to view the snapshot details and edit certain structures in a limited capacity.

1. A snapshot contains data relating to the image set such as the number of slices, who imported the image set, the import date and the UID.
2. A snapshot also contains a list of the structures that were imported.
3. The user may choose to set the active variant for any structure present in the snapshot.
4. Structures not defined in the site config (a custom structure) are denoted with a “c” beside it. These structures have the ability to be edited in a limited capacity. The planner may choose to change the structure variant, color, and structure type. The planner may also choose to enter any notes that may be helpful at this point.