3.8 DICOM Media Storage and File Format Definitions

The following definitions are commonly used in this Part of the Standard:

Application Profile

A Media Storage Application Profile defines a selection of choices at the various layers of the DICOM Media Storage Model that are applicable to a specific need or context in which the media interchange is intended to be performed.

DICOM File Service

The DICOM File Service specifies a minimum abstract view of files to be provided by the Media Format Layer. Constraining access to the content of files by the Application Entities through such a DICOM File Service boundary ensures Media Format and Physical Media independence.


A DICOM File is a File with a content formatted according to the requirements of this Part of the DICOM Standard. In particular such files shall contain, the File Meta Information and a properly formatted Data Set.


A unique and mandatory DICOM File within a File-set that contains the Media Storage Directory SOP Class. This File is given a single component File ID, DICOMDIR.


A File is an ordered string of zero or more bytes, where the first byte is at the beginning of the file and the last byte at the end of the File. Files are identified by a unique File ID and may by written, read and/or deleted.

File ID

Files are identified by a File ID that is unique within the context of the File-set they belong to. A set of ordered File ID Components (up to a maximum of eight) forms a File ID.

File ID Component

A string of one to eight characters of a defined character set.

File Meta Information

The File Meta Information includes identifying information on the encapsulated Data Set. It is a mandatory header at the beginning of every DICOM File.


A File-set is a collection of DICOM Files (and possibly non-DICOM Files) that share a common naming space within which File IDs are unique.

File-set Creator

An Application Entity that creates the DICOMDIR File (see Section 8.6) and zero or more DICOM Files.

File-set Reader

An Application Entity that accesses one or more files in a File-set.

File-set Updater

An Application Entity that accesses Files, creates additional Files, or deletes existing Files in a File-set. A File-set Updater makes the appropriate alterations to the DICOMDIR file reflecting the additions or deletions.

DICOM File Format

The DICOM File Format provides a means to encapsulate in a File the Data Set representing a SOP Instance related to a DICOM Information Object.

Media Format

Data structures and associated policies that organize the bit streams defined by the Physical Media format into data file structures and associated file directories.

Media Storage Model

The DICOM Media Storage Model pertains to the data structures used at different layers to achieve interoperability through media interchange.

Media Storage Services

DICOM Media Storage Services define a set of operations with media that facilitate storage to and retrieval from the media of DICOM SOP Instances.

Physical Media

A piece of material with recording capabilities for streams of bits. Characteristics of a Physical Media include form factor, mechanical characteristics, recording properties and rules for recording and organizing bit streams in accessible structures

Secure DICOM File

A DICOM File that is encapsulated with the Cryptographic Message Syntax specified in RFC 2630.

Secure File-set

A File-set in which all DICOM Files are Secure DICOM Files.

Secure Media Storage Application Profile

A DICOM Media Storage Application Profile that requires a Secure File-set.