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": [ "<VR>", "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
Don't forget to pick an odd group number (odd groups are reserved for private tagging). If you can predict through reasearch/collection which private tags are already used, you might be better off to selecting a group number that won't give you headaches down the road.
Still, if say "5555,AAxx" is already reserved, you can resort to "5555,ABxx" without a problem.
Let me know if you have any further questions.
Best,
--
Luiz Eduardo