DICOM tags to use to mark instances for inclusion in a particular project


I posted this question on the comp.protocol.dicom group (sorry for cross-posting) but this might prompt a response from the Orthanc community:

what would be the DICOM tags to use to mark instances for inclusion in a particular project. Say I want to tag instances with a project code (e.g. “MyProject”) to easily retrieve all images/SR belonging to this collection?

I plan on using the studies/{id}/modify method to tag studies belonging to a particular project.

I search the forum but could not find a satisfying answer.



Hi, Philippe!

I understand your tag to be very specific. Because of that, I suggest you work with private tags. I apologise if you’re aware of that which I’m about to write, but I struggled a lot with it in the past so I’ll try to save you some time.

You’ll want to define a custom dictionary in Orthanc configuration. Suppose your company name is ACME. The Dictionary tag in Orthanc.json would read something like this:


“Dictionary”: {
“2345,FA01”: [ “”, “ProjectCode”, 1, 1, “ACME” ]


NOTE: VR is the Value Representation, the type of the ProjectCode tag

Then you’ll want to place TWO tags in your image:

  • The reservation tag formatted as “2345,00FA”: the 2345 is the same as the group number from the tag itself, whereas the 00FA element tells us you’re reserving from “2345,FA00” to “2345,FAFF”
  • The tag per se, as presented above