The Inventory Creation SOP Class allows an SCU Application Entity to request a peer SCP Application Entity to produce an Inventory of the Studies, Series, and Instances that it manages. The request for the Inventory may include a set of matching keys to limit the Scope of Inventory to Studies with corresponding Attribute values. The Inventory produced is encoded in one or more SOP Instances of the Inventory SOP Class (see Annex GG). Success or failure of Inventory production is indicated by a notification from the SCP to the SCU. The SCU may then access the Inventory SOP Instances by a mechanism supported by the SCP, including Query/Retrieve (see Annex JJ), Non-Patient Instance Services (see Section C.6.2.1 in PS3.4), or a non-DICOM file access protocol. See additional explanatory information in Annex YYYY “Inventories (Informative)” in PS3.17.
The SOP Class defines five states for the Inventory production with associated state transitions (see Figure KK.2-1). Some of the transitions are associated with receipt and processing of N-ACTION requests (labeled arrows in the figure).
After the Initiate request, production is in the PROCESSING state. Production will proceed and reach one of two terminal states without further N-ACTION operations - COMPLETE or FAILURE.
Production may be PAUSED, either due to an N-ACTION request or due to conditions internal to the SCP, for example, a temporary shortage of resources. Production may be returned to the PROCESSING state by a Resume request or by SCP internal actions.
From either the PROCESSING or PAUSED state the production may be changed to the CANCELED terminal state by a Cancel request or by SCP internal actions.