Modality worklist and MPPS

Routes can serve the modality worklist: orders arrive from the RIS over HL7, modalities query them with DICOM, and report back with MPPS. Every node serves the same worklist, kept by the central service.

Orders from HL7

Turn on the HL7 port in Configuration › Settings › HL7 and list the addresses that may send (the RIS, the interface engine; HL7 has no sign-in). Every node then accepts HL7 v2 over MLLP, optionally over TLS.

• Orders (ORM^O01, OMI^O23, OMG^O19) become worklist items, one per ORC with its OBR. NW/XO adds or changes an item (matched on its order number), CA cancels it, DC discontinues it, and SC with ORC-5 IP/CM marks it started or completed.
• Patient updates (ADT^A08, A31) change the patient on their items. Merges (ADT^A40, A18, A34) move items to the surviving ID, and can add the prior ID to a patient ID map.
• Fields: patient PID-3, PID-5, PID-7, PID-8; accession number IPC-1 or OBR-18; requested procedure IPC-2 or OBR-19; Study Instance UID IPC-3 or ZDS-1 (else one made from the order); modality IPC-5 or OBR-24; procedure OBR-4; scheduled time TQ1-7, OBR-27.4, ORC-7.4, OBR-36 or OBR-6; station IPC-9; physicians PV1-8 and OBR-16.
• A node acknowledges a message with AA once applied, AE when it cannot be used, and AR while the central service cannot be reached (the RIS sends it again).

The same messages can also be routed to other systems.

Modalities query it

A source’s senders may query the worklist when the source allows it (May query the worklist), optionally only for some modalities. Matching keys: Patient ID, Issuer, Patient’s Name (from its start, or with * and ?), Accession Number, Requested Procedure ID, Study Instance UID, and in the Scheduled Procedure Step: Modality, Scheduled Station AE Title, start date and time (single values or ranges) and step ID. Scheduled and started items are offered.

Each node keeps a copy of the worklist and answers from it while the central service cannot be reached.

Performed procedure steps (MPPS)

Modalities report examinations with MPPS N-CREATE and N-SET, when their source allows it (on by default with the worklist):

• IN PROGRESS puts the items it names in progress; COMPLETED completes them; DISCONTINUED schedules them again.
• An unscheduled examination is recorded and changes nothing.
• While the central service cannot be reached, the modality is told to send it again.

MPPS go on to other systems (a PACS, a dose registry) when the source names them: queued on the node and sent in order, retried while the destination cannot be reached, with an alert after 15 minutes.

For modalities without MPPS, Complete an item when its study arrives completes items by Study Instance UID, or accession number and patient ID.

Status back to the RIS

Under Settings › HL7 status update receivers: whenever an item’s status changes other than by the RIS (MPPS, a study arriving, the console), the central service sends the receiver an order status update (ORM^O01, ORC-1 SC, ORC-5 IP, CM, SC, DC or CA), in order, retried until it is taken. A receiver can take only the orders of some sending applications, so each RIS hears about its own orders.

The Worklist view

History › Worklist (history role; audited) lists the items; administrators can complete, cancel or reopen one the RIS never closed. Items are kept Keep worklist items days after their scheduled date.