Create an xml file with your tags.
Like this -->
<?xml version="1.0" encoding="UTF-8"?>
<dictionaries>
<dictionary creator="STENTOR">
<tag group="0073" element="0010" vr="ST" vm="1">Stentor Private Tag</tag>
<tag group="0073" element="1001" vr="ST" vm="1">Sending Hostname</tag>
<tag group="0073" element="1002" vr="ST" vm="1">Sending IP Address</tag>
<tag group="0073" element="1003" vr="ST" vm="1">Sending AE Title</tag>
<tag group="0073" element="1006" vr="UI" vm="1">Sending Transfer Syntax</tag>
</dictionary>
</dictionaries>
Then in your code, something like this -->
DicomDictionary.Default.Load("Path\\privateDictionary.xml", DicomDictionaryFormat.XML);