Radiotherapy objects were DICOM’s first foray into non-image Composite Instances - i.e. data to be stored long-term without pixel data. They are stored, handled, retrieved etc. exactly the same way as images. There are 7 radiotherapy objects:

• Radiotherapy Image
• Radiotherapy Dose
• Radiotherapy Structure Set
• Radiotherapy Plan
• Radiotherapy Beams Treatment Record
• Radiotherapy Brachy Treatment record
• Radiotherapy Treatment Summary

All these can of course be handled by DicomObjects, but only the Image and Dose can be displayed in a viewer. Not that although “Dose” images have pixel data, this is a pseudo-image, showing an intended dose distribution. it is also unique in DICOM, using 32 bit pixel values. This can be displayed by recent versions of DicomObjects.