RT Treatment Delivery Workflow

Treatment Delivery Workflow (TDW) radiation oncology treatment delivery workflow

Summary

In this profile a single system, a Treatment Delivery Device (TDD) acquires delivery information from a Treatment Management System (TMS), and performs a treatment delivery using internal verification (see DICOM Supplement 74). Other optional activities such as verification image acquisition, registration, and patient positioning may be performed by this TDD, but these are not explicitly scheduled in this profile.

Benefits

Provides Standards-based interaction between a TMS and a TDD for patient treatment selection

Details

The Treatment Delivery Workflow integration profile involves the flow of DICOM data necessary for treatment delivery between Treatment Management System (TMS) actors and Treatment Delivery Devices (TDDs). This profile grew out of work on the Integrated Positioning and Delivery Profile, where implementation was found to specify too many required elements for some delivery devices. A number of delivery machines either do not handle positioning interactions at all, or they are not externalized in significant or easily modifiable ways. This profile handles the interaction in workflow when the delivery device is largely only concerned with delivery scheduling.

The intention is to develop a progression of profiles that will implement workflow features in radiation oncology. The intended sequence of development for these profiles is as follows:

Phase 1: Scheduled workflow for integrated patient positioning and delivery, treatment delivery, and discrete patient positioning and delivery.
Phase 2: Scheduled workflow for remaining procedure step types in radiation oncology. These steps may include items such as simulation, planning, plan review, and treatment review, as well as other modes of positioning and delivery. At this stage, the profile will then cover the vast majority of cases in radiation therapy, and enable charge capture by the Treatment Management System or billing system.

Managed Workflow can be used to support a number of other common use case scenarios currently relevant in the clinic. For example, if a number of fractions are delivered, then subsequently the stored registration images and position registration results can be transmitted from the archive to a treatment planning system (TPS). The TPS could then correlate the images, deform the original structures onto the new 3D datasets, recalculate the doses to PTVs and organs at risk, and evaluate a potential need for replanning. These operations can be initiated by non-managed transfer of necessary data using Storage or Query/Retrieve, but ultimately the goal is to manage all departmental activities using Managed Workflow.
Phase 3: ADT (admission, discharge, and transfer) support. This profile will enable a Treatment Management System to acquire patient demographic information from a Hospital Information System (via the HL7 protocol), based upon existing IHE patient registration profiles. This functionality has already been implemented in some commercially available products and this phase may potentially be combined with Phase 2.
Phase 4: Non-managed workflow. Special cases such as emergency treatments may result in performed procedures that have no corresponding Unified Procedure Step. This profile will be concerned with updating the Treatment Management System to take this into account, so that the performed items are then recorded and billed through the normal processes. This phase may require the RT Course IOD being developed as part of DICOM WG7 work on second-generation RT objects.
Phase 5: Partially-managed workflow and media archive. This profile will support situations where some procedures (e.g. CT acquisition and an initial plan) have not been performed under managed workflow, but the output objects from those procedures are introduced into the workflow environment via media archive. It will also support generation of media archives. This phase may require the RT Course IOD being developed as part of DICOM WG7 work on second-generation RT objects.

Treatment Completion

An important use case associated with treatment delivery is that of treatment completion following a delivery interruption.

If the delivery interruption is of a transient nature (e.g. a temporary issue with the delivery machine, or a patient position issue caused temporary interruption of the delivery), then the Performing Device may choose to manage the completion internally, and notify the TMS that the UPS has finally completed normally.
If the delivery interruption leads to the UPS being moved to the ‘CANCELED’ state, this requires that a new UPS be scheduled (for example, if the completion requires replanning, or needs to be performed in a different time slot). The TMS shall then manage the new UPS, specify a Text Value of ‘CONTINUATION’ in the Scheduled Processing Parameters Sequence when returning a query result, and supply the Start Meterset of the continuation treatment in the Delivery Instruction.

Profile Preconditions

The Treatment Delivery Workflow profile requires that the Treatment Management System (TMS) has previously received any information needed to effectively respond to queries issued by the Performing Devices that is not generated by the TMS itself. In particular, the TMS must know the SOP Instance UIDs of SOP Instances (such as an RT Plan instance) to be supplied in the Input Information Sequence. It is a precondition of the query transactions that such information has been supplied to the TMS where necessary. For this profile, such information is assumed to have been communicated in a way not covered by the profile. In future profiles, previously executed managed workflow steps will be used to communicate such data.