DICOM PS3.18 2024c - Web Services

8.8 Character Sets

HTTP uses charset names to indicate or negotiate the character encoding of textual content in representations [RFC6365] Section 3.3.

Character sets may be identified using the value in the IANA Preferred MIME Name column in [IANA Character Sets].

Character sets may also be identified by using the DICOM Defined Terms for the character set (see Annex D, Section C. in PS3.3 , and Section “Encoding of Character Repertoires” in PS3.5), which shall be quoted strings since they contain the space (' ') character.

The syntax is:

charset = token / defined-term / DQUOTE defined-term DQUOTE



A case-insensitive charset name from the Preferred MIME Name in the IANA Character Set Registry.


See Section C. “Specific Character Set” in PS3.3.

The origin server shall support the "UTF-8" charset name for RESTful Retrieve Rendered transaction but is not required to support the DICOM Defined Term "ISO_IR 192". Some DICOM Defined Terms for character sets contain space characters, and shall be enclosed in double quotes in HTTP header fields and percent encoded in URIs.

The Conformance Statement shall document all supported character sets. The Retrieve Capabilities response for all RESTful Services shall also document all supported character sets.

A request without any Character Set Query Parameter or Accept-Charset header field implies that the user agent will accept any character set in the response.

Annex D contains a mapping of some Specific Character Set (0008,0005) Defined Terms to IANA charset tokens.

8.8.1 Acceptable Character Sets

The term Acceptable Character Sets denotes the character sets that are acceptable to the user agent in the response. The Acceptable Character Sets are those specified in:

  • the "charset" media type parameter

  • the character set Query Parameter

  • the Accept-Charset header field

  • the default character set for the media type, if any

When Acceptable Character Sets contains a list of one or more Defined Terms they shall be ordered by the user agent as specified in Section C. “Specific Character Set” in PS3.3, and Section “Encoding of Character Repertoires” in PS3.5. This is especially important for ISO 2022 character sets.

Any charset values that are not valid or not supported shall be ignored by the origin server.

DICOM PS3.18 2024c - Web Services