Describes the services that DICOM applications can render to each other; they encode SOPs supported on the communicating AEs.
Generally equivalent to a SOP class, the specification used to define the information to exchange in a message; does not represent a specific instance of the data object, but rather a class of similar data objects that have the same properties. Examples: MR image storage, CT image storage, MWL.
data dictionary element
A unit of information as defined by a single entry in the data dictionary. An encoded Information Object Definition (IOD) Attribute that is composed of, at a minimum, three fields: a Data Element Tag, a Value Length, and a Value Field. For some specific Transfer Syntaxes, a Data Element also contains a VR Field where the Value Representation of that Data Element is specified explicitly.
picture archiving and communication system (PACS)
A system that acquires, transmits, stores, retrieves, and displays digital images and related patient information from a variety of imaging sources and communicates the information over a network.
Set of DICOM network services used over an association, as negotiated between application entities; includes abstract syntaxes and transfer syntaxes.
Each network transfer begins with an association establishment (DICOM handshake), when the two connecting applications exchange information about each other. This information is called the presentation context; if the two applications can match their contexts, they can connect and start SCU-SCP processing.
radiology information system (RIS)
System used by radiology departments to store, manipulate, and distribute patient radiological data and imagery. The system generally comprises of patient tracking and scheduling, result reporting, and image tracking capabilities.
service class provider (SCP)
Role of an application entity that provides a DICOM network service; typically, a server that performs operations requested by another application entity (Service Class User). Examples: Picture Archiving and Communication System (image storage SCP, and image query/retrieve SCP), Radiology Information System (modality worklist SCP).
service-object pair (SOP) class
The specification of the network or media transfer (service) of a particular type of data (object); the fundamental unit of DICOM interoperability specification. Examples: verification, CT image storage, print job.
transfer syntax (standard and private)
Encoding used for exchange of DICOM information objects and messages. Allows application entities to unambiguously negotiate the encoding techniques they are able to support (for example, data element structure, byte ordering, compression), thereby allowing these application entities to communicate.
See DICOM Transfer Syntax for a table of standard values. Manufacturers may also define private transfer syntax values for use among their own devices.
value representation (VR)
Format type of an individual DICOM data element, such as text, an integer, a person’s name, or a code. DICOM information objects can be transmitted with either explicit identification of the type of each data element (Explicit VR), or without explicit identification (Implicit VR). With Implicit VR, the receiving application must use a DICOM data dictionary to look up the format of each data element.