This is the ValueSet that contains all the codes in KDL Radiologie-Kategorien (https://fhir.cognovis.de/praxis/ValueSet/kdl-radiology-category) and KDL Radiologie-Kategorien (https://fhir.cognovis.de/praxis/ValueSet/kdl-radiology-category). E.g. what you have to deal with if you get resources containing codes in either of them