Currently the loading of RTDose and RTStruct is only supported via the dicom editor plugin. It should also be supported by the normal loading infrastructure (open file, dragNdrop). Add Reader services for RTStruct and RTDose. They should be part of the DICOMRT module and use the available reader implementations.
Services should have a higher priority then other dicom readers but only notify readability if the data has the correct modality (RTDose or RTStruct).