DD.2 GENERAL PURPOSE WORKLIST EXAMPLE (INFORMATIVE)

DD.2.1 Introduction

This section provides an example of message sequencing when using the General Purpose Worklist SOP Classes. This section is not intended to provide an exhaustive set of use cases but rather an informative example. There are other valid message sequences that could be used to obtain an equivalent outcome and there are other valid combinations of actors that could be involved in the workflow management.

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Figure DD.2-1 Example of General Purpose Worklist Message Sequencing

Figure DD.2-1 illustrates a message sequence example in the case where a General Purpose Scheduled Procedure Step ( GP-SPS) is performed using a single General Purpose Performed Procedure Step ( GP-PPS) that completes normally. Further examples could be constructed for discontinued, unscheduled, group, cooperative and other use cases but are not considered in this informative section. Italic text in Figure DD.8-1 denote messages outside the scope of General Purpose Worklist that will typically be conveyed using other DICOM Services such as Storage, Storage Commitment and Query/Retrieve.

The Actors shown in Figure DD.2-1 are:

Acquisition Modality : Acquires the images that are input for the General Purpose steps

Archive : Stores SOP Instances (images, structured reports, etc)

Workflow Manager : Manages worklists and tracks performance of procedures

Performing Device : Performs the tasks specified by the worklist and creates results

DD.2.2 Transactions and message flow

In Figure DD.2-1 the following transactions and messages are shown.

DD.2.2.1 Acquisition Complete

The Acquisition Modality reports that the acquisition is complete. This message would typically be conveyed using the Modality Performed Procedure Step SOP Class. Upon receiving this message the Workflow Manager can update its worklist of General Purpose Scheduled Procedure Steps to indicate that input is available and to identify these composite SOP instances.

DD.2.2.2 Store SOP Instances

The Acquisition Modality stores SOP Instances to the Archive. This message would typically be conveyed using the Storage and Storage Commitment Service Classes. This message could equally be transmitted prior to the Acquisition Complete message.

DD.2.2.3 Query GP-SPS

The Performing Device queries the Workflow Manager for General Purpose Scheduled Procedure Steps (GP-SPS) matching its search criteria. For example, all worklist items with General Purpose Scheduled Procedure Step Status (0040,4001) of “SCHEDULED”, Input Availability Flag (0040,4020) of “COMPLETE” and Scheduled Human Performers Sequence (0040,4034) of the currently active user. This message is conveyed using the C-FIND request primitive of the General Purpose Worklist SOP Class.

DD.2.2.4 Receive GP-SPS

The Performing Device receives the set of General Purpose Scheduled Procedure Steps (GP-SPS) resulting from the Query GP-SPS message. The Receive GP-SPS message is conveyed via one or more C-FIND response primitives of the General Purpose Worklist SOP Class, each response with status pending containing the requested attributes of a single GP-SPS worklist item.

DD.2.2.5 Transmit SOP Instances to be Used

The Archive transmits the SOP Instances to be used as input information during the task to the Performing Device. This message would typically be conveyed using the Storage Service Class which could be initiated by the Performing Device via the Query/Retrieve Service Class based on information contained in the GP-SPS, or could also be initiated by the Archive or Workflow Manager in order to ensure the necessary SOP Instances are available before use.

DD.2.2.6 Update GP-SPS (IN PROGRESS)

The Performing Device updates a General Purpose Scheduled Procedure Step (GP-SPS) managed by the Workflow Manager to have the status IN PROGRESS upon starting work on the item. The SOP Instance UID of the GP-SPS will normally have been obtained via the Receive GP-SPS message as a worklist item. This message is conveyed using the N-ACTION primitive of the General Purpose Scheduled Procedure Step SOP Class with an action type “Request GP-SPS Status Modification”. This message allows the Workflow Manager to update its worklist and permits other Performing Devices to detect that the GP-SPS is already being worked on.

DD.2.2.7 Create GP-PPS (IN PROGRESS)

The Performing Device creates a new General Purpose Performed Procedure Step (GP-PPS) instance on the Workflow Manager upon starting work on a General Purpose Scheduled Procedure Step (GP-SPS). This message is conveyed using the N-CREATE primitive of the General Purpose Performed Procedure Step SOP Class. Upon creation, the GP-PPS must have a GP-PPS Status of IN PROGRESS, should contain references to the related GP-SPS and have values for any other attributes known when starting the GP-PPS.

DD.2.2.8 Set GP-PPS (COMPLETED)

The Performing Device sets the GP-PPS Status to COMPLETED upon completion of the performed step and includes details of the performed step and references to any results (results are themselves conveyed by the Store Results message). This message is conveyed using the N-SET primitive of the General Purpose Performed Procedure Step SOP Class. Upon completion, all mandatory attributes of the GP-PPS must have been assigned a value.

DD.2.2.9 Update GP-SPS (COMPLETED)

The Performing Device updates the GP-SPS Status to COMPLETED upon completion of the scheduled step. This message is conveyed using the N-ACTION primitive of the General Purpose Scheduled Procedure Step SOP Class with an action type “Request GP-SPS Status Modification”. This message informs the Workflow Manager that the GP-SPS is now complete and that further GP-PPS will not be created.

DD.2.2.10 Store Results

The Performing Device stores any generated results to the Archive. This message would typically be conveyed using the Storage and Storage Commitment Service Classes and may contain Structured Reports, Images or other relevant Composite SOP Instances. This message could equally be transmitted prior to the Set GP-PPS (COMPLETED) message. References to the results are associated with the GP-PPS in the Set GP-PPS (COMPLETED) message.