DICOM PS3.17 2019a - Explanatory Information

BBB Unified Procedure Step in Radiotherapy (Informative)

BBB.1 Purpose of this Annex

This annex provides examples of message sequencing when using the Unified Procedure Step SOP Classes in a radiotherapy context. 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.

The current use cases assume that tasks are always scheduled by the scheduler prior to being performed. It does not address the use case of an emergency or otherwise unscheduled treatment, where the procedure step will be created by a different device. However, Unified Procedure Step does provide a convenient mechanism for doing this.

The use cases addressed in this annex are:

  • Treatment Delivery Normal Flow - Treatment Delivery System (TDS) performs the treatment delivery that was scheduled by the Treatment Management System (TMS). Both the "internal verification" and "external verification" flavors are modeled in these use cases.

  • Treatment Delivery - Override or Additional Information Required. Operating in the external verification mode, the Machine Parameter Verifier (MPV) detects an out-of-tolerance parameter of missing information, and requests the user to override the parameter or supply or correct the missing information. This use case addresses the situation where the 'verify' function is split from the TDS, but does not address verification of a subset of parameters by an external delivery accessory such as a patient positioner.

DICOM PS3.17 2019a - Explanatory Information