R Instance Availability Notification Service Class (Normative)

The Instance Availability Notification Service Class defines an application-level class-of-service that allows one DICOM AE to notify another DICOM AE of the presence and availability of SOP instances that may be retrieved. The AE from which such SOP Instances can later be retrieved may or may not be the SCU performing the notification.

The SCU implementation defines the conditions under which it provides the notification. Certain SCUs may provide notification for arbitrary sets of SOP Instances, while other SCUs may provide notification when they determine that the instances associated with a Procedure Step or a Requested Procedure are available. The SCU is required to document in its Conformance Statement the nature of its notification decisions (e.g., frequency of notifications, retrieve capabilities and latency, etc.).

Once the SCU has provided notification about availability of the SOP Instances, the SCP may use that information in directing further workflow, such as in populating the Input Information Sequence when forming a Unified Procedure Step. These types of policies are outside the scope of this Standard, however, the SCP is required to document these policies in its Conformance Statement.

The SCU of this Service Class is not required to assure that the study, procedure step or any workflow-related entity is "complete"; indeed no semantics other than the concept of "availability" is expressed or implied by the use of this service.