Service Class User. This is a DICOM term. A Service Class User is a 'client', where a client is a workstation or modality, and hence uses a service provided by the SCP. An example of this is the a modality (which acts as a service class user (SCU) when sending images to an archiving device (which acts as a service class provider (SCP)). See Digital Imaging and Communications in Medicine (DICOM), Server and Service Class Provider.