This is the ValueSet that contains all the codes in FHIR Device Types (http://hl7.org/fhir/ValueSet/device-kind) and Brachytherapy Device Type Value Set (http://hl7.org/fhir/us/codex-radiation-therapy/ValueSet/codexrt-brachytherapy-device-type-vs). E.g. what you have to deal with if you get resources containing codes in either of them