Working with Tags

The Tag of a Data Element consists of an ordered pair of 16-bit values that represent a Group Number and an Element Number. The Tag indicates the type of information stored in the Value Field of the Data Element. There are a number of Tags that are standard for the DICOM file format. In addition to the standard Tags, user-defined Tags may also be added.

LEADTOOLS maintains a table (or list) internally of all available Tags, standard and user-defined. In this documentation the table of available value representations will be referred to as the Data Element Tag Table. Also provided in this documentation is a table of the default values for the standard Tags. To see these default values, refer to the Default Data Element Tags.

LEADTOOLS provides a number of methods for maneuvering through and modifying the Data Element Tag Table. All methods pertaining to the Data Element Tag Table are in the class DicomTagTable.

For maneuvering through the Data Element Tag Table, LEADTOOLS provides the following methods:

• DicomTagTable.GetFirst

• DicomTagTable.GetLast

• DicomTagTable.GetPrevious

• DicomTagTable.GetNext

• DicomTagTable.GetCount

To find specific items, based on either the Tag or an index into the table, use DicomTagTable.Find and DicomTagTable.FindByIndex.

To insert new items in the Data Element Tag Table, call DicomTagTable.Insert.

You can delete individual items from the table using DicomTagTable.Delete, or you can delete all items from the table, using DicomTagTable.Reset.

To change the name of an item already in the table, call DicomTagTable.SetName.

To determine whether you have a valid Tag object, call DicomTagTable.Exists.

Finally, to reset the Data Element Tag Table to the default values, use DicomTagTable.Default. For more information on tags, refer to An Overview of the DICOM File Format or the DICOM Standard.