DICOM Specification Overview: Private Data Elements

Implementations may require communication of information that cannot be contained in Standard Data Elements.

Private Data Elements are intended to be used to contain such information. Private Data Elements have the same structure as Standard Data Elements specified earlier in Section 7.1 of the DICOM Standard (i.e., Data Element Tag field, optional VR field, length field, and value field). The Group Number used in the Element Tag of Private Data Elements shall be an odd number. Private Data Elements shall be contained in the Data Set in increasing numeric order of Data Element Tag. The Value Field of a Private data element shall have one of the VRs specified by this standard in Section 6.2 of the DICOM Standard.

For each Information Object Definition or SOP Class Definition, certain Data Elements are required (Data Element Type 1, 1C, 2, or 2C) as specified in PS 3.3 and PS 3.4 of the DICOM Standard. Private Data Elements shall not be used in place of required Standard Data Elements.