DICOM PS3.4 2024c - Service Class Specifications

CC.2.2.2 Service Class User Behavior

An SCU uses N-ACTION to request to the SCP that the state of a UPS Instance be changed to CANCELED as shown in Figure CC.1.1-1. Since all UPSs are created as instances of the UPS Push SOP Class, the Requested SOP Class UID (0000,0003) in the N-ACTION request shall be the UID of the UPS Push SOP Class. See Section CC.3.1 for further details.

The SCU may include a Reason For Cancellation and/or a proposed Procedure Step Discontinuation Reason Code Sequence.

The SCU may also provide a Contact Display Name and/or a Contact URI for the person with whom the cancel request may be discussed.


An N-ACTION Status Code indicating success means that the Request was accepted, not that the UPS has been canceled. The system performing the UPS is not obliged to honor the request to cancel and in some scenarios, may not even receive notification of the request. See Section CC.2.4.

At any time after receipt of the N-ACTION response, the SCU may release the association on which it sent the N-ACTION request.

To cancel an IN PROGRESS UPS that the SCU is itself performing, the SCU shall instead use the Change UPS State action as described in Section CC.2.1.

DICOM PS3.4 2024c - Service Class Specifications