DICOM PS3.5 2024c - Data Structures and Encoding

7.6 Repeating Groups

Multiple Overlay Planes can be associated with a single Image (see PS3.3). Standard Data Elements with even Group Numbers 6000-601E represent Overlay Planes. This range of Group numbers is known as a Repeating Group. This use of Group Numbers is a remnant of older versions of this Standard, which associated a semantic meaning with particular Groups.

In this range of Group Numbers, Standard Data Elements that have identical Element Numbers have the same meaning within each Group (and the same VR, VM, and Data Element Type). The notation 60xx is used for the Group Number in Data Element Tags when referring to a common Data Element across these Groups (see PS3.6). Groups 60xx are called Repeating Groups because of these characteristics.

Repeating Groups shall only be allowed in the even numbered Groups 6000-601E. In the future, Data Elements with VRs of SQ shall be used to serve a similar purpose.


  1. Encoding of Curves in the even Group Numbers 50xx was previously defined but has been retired. See PS3.5-2004

  2. Private Groups in the odd Group Numbers 6001-601F may still be used, but there is no implication of repeating semantics, nor any implied shadowing of the standard Repeating Groups.

DICOM PS3.5 2024c - Data Structures and Encoding