The SCU uses the N-SET to request the SCP to update an applicable Machine Verification instance. The SCU shall specify the SOP Instance to be updated and shall specify the list of attributes for which the Attribute Values are to be set. The attributes in the Conventional/Ion Control Point Verification Sequence represent the Treatment Delivery System’s actual geometric values at the time the N-SET request is issued and therefore, the Conventional/Ion Control Point Verification Sequence shall always contain one sequence item. The Referenced Control Point Index shall be zero for NORMAL treatments, and may be greater than zero for CONTINUATION treatments.

Within an attribute sequence such as the General Machine Verification Sequence, Conventional Machine Verification Sequence, and Ion Machine Verification Sequence, values for all required attributes must be supplied with each N-SET, or else the missing attributes will have any previously set values removed from the SOP Instance. Existing parameters may be cleared by sending an empty sequence or attribute. The MPV’s Conformance Statement shall specify the set of attributes that it requires for verification.

The SCU shall set the new values for the specified Attributes of the specified SOP Instance. The SCP shall then compare the values of Attributes of the specified SOP Instance to the values of the same Attributes found in the RT Plan referenced in N-CREATE. Values shall be compared using the tolerance values also found in the referenced RT Plan. The result of this comparison shall be available for use when the SCU requests the Treatment Verification Status using an N-GET.