DICOM PS3.3 2024c - Information Object Definitions

F.3.2 Modules of the Basic Directory Information Object

Attributes of the Basic Directory IOD are defined with a Type designation that indicates if a specific Attribute is required for all Media Storage Operations (see Chapter 5).

F.3.2.1 File-set Identification Module

Table F.3-2 specifies the Attributes of the File-set Identification Module, which identify a File-set.

Table F.3-2. File-Set Identification Module Attributes

Attribute Name



Attribute Description

File-set ID



User or implementation specific Identifier (up to 16 characters). For definition, see PS3.10. The File-set ID is intended to be a short human readable label to easily (but not necessarily uniquely) identify a specific File-set to facilitate operator manipulation of the physical media on which the File-set is stored. Assignment of Value and semantics are environment specific.

File-set Descriptor File ID



ID of a File (in the same File-set) used for user comments related to the File-set (e.g., a README file). The Specific Character set used may be specified in the Specific Character Set of the File-set Descriptor File (0004,1142).


This File is not DICOM formatted (no Preamble, nor DICM Prefix and Meta Information).

Specific Character Set of File-set Descriptor File



Character set used in the File-set Descriptor File with a File ID as specified in File-set Descriptor File ID (0004,1141). Required to specify the expanded or replacement character set. If absent, only the Basic Graphic set is used. See Section C. for Defined Terms.


Every File-set is assigned a File-set UID when created. The File-set UID need not be duplicated as a Type 1 Attribute of the File-set Identification Module. It is conveyed as the SOP Instance UID of the Basic Directory IOD. It is included in the DICOMDIR File Meta Information (see PS3.10)

DICOM PS3.3 2024c - Information Object Definitions