Acknowledge and will attempt to add the code to the  TotalRadiationDoseDelivered  extension. Digging deep into StructureDefinitions, there appears to be a place for a semantic code in ElementDefinition. The spot to put this is the extension's StructureDefinition in the attribute snapshot.element.code (and differential.element.code): "differential": { "element": [ { "id": "Extension", "path": "Extension", "short": "TotalRadiationDoseDelivered", "definition": "The total amount of radiation dose delivered for the course of therapy. (source: SNOMED, ASTRO)", "min": 0, "max": "*" } , The change may be invisible in the IG. It is up to the IG Publisher to show it. Proposed Resolution: Persuasive