DICOM PS3.3 2019a - Information Object Definitions

C.34.9.4 Modifiable Constraint Flag

New protocol instances derived from original protocol instances with different constraints on a given Attribute "modify" the constraint. This flag may be used by devices that create original instances to specify which constraints can be modified by other devices in derived instances.

For example, a CT device that creates a Defined Procedure Protocol, may indicate that the Element Name (0018,9922) of the Acquisition Protocol Element, or the CTDIvol Notification Trigger (0018,9942) constraints may be modified, but the Spiral Pitch Factor (0018,9311) constraint may not since the latter depends on correlated changes by the device to other Attributes. Such information would be useful to a protocol management workstation that is letting its operator make changes to the CTDIvol Notification Trigger.


There is a difference between these "derivation" modifications and what an operator does at the time of protocol execution. At execution time, the operator is using the CT device to change Selector Attribute values and those values are compared to the Constraint Values in the Constraint Macro of the Defined Protocol. The result may (or may not be) stored in a Performed Procedure Protocol instance. At derivation time, an operator is using a workstation to change Constraint Values in the Constraint Macro and store a new Defined Procedure Protocol Instance.

DICOM PS3.3 2019a - Information Object Definitions