Re: understanding DICOM workflow
> > Yes. The only problem would be to remove the worklist once
> > the device has uploaded its acquisition to Orthanc
> How does that happen _now_ with the current ModalityWorkList
> plugin ? (without regard to anything I said would be useful
> from a GNUmed point of view)
The current plugin will re-read the folder for each incoming worklist request. It is up to the system administrator to properly sync the worklists in this folder using system scripts living outside Orthanc.
> I would have assumed there's two ways:
> There's a standard DICOM way of saying "remove this
> worklist entry" (regardless of whether it is completed).
This process is typically done by sending HL7 messages, not through DICOM messages.
Maybe the N-DELETE from DICOM "normalized services" might be used for this purpose, but I'm not sure as I'm not an expert in that field. In typical workflows, such "normalized services" are mainly used for MPPS (N-CREATE to setup a worklist, N-SET to update a worklist after some acquisition). Anyway, Orthanc does not currently support "normalized services", as the software is above all designed for the workflows afterwards the DICOM image is available (in other terms, Orthanc is currently not a RIS).
> Delete the corresponding *.wl from the worklist directory
> being watched by Orthanc.
Yes, this is how it currently works. This is also the convention of the standard command-line tool "dcmwlm" from DCMTK.
> > (which will necessitate a custom "OnChange" callback watching DICOM
> > files entering Orthanc), or if GNUmed invalidates some
> > worklist.
> I agree that there would be a need for a second REST API
> call, namely to remove a give MWL entry.
Yes. As written above, a HL7 plugin for Orthanc *could* also be written for this purpose, but this is probably an overkill wrt. simply adding a REST callback to handle HTTP DELETE.
> Wait, does the ServeFolder plugin help any ? Does it support
> put/delete of files in the served directory ?
Not yet. As written above, it is up to the system administrator to write the script that will keep the content of the folder in sync.
> > However, I currently have no time to work on this extension
> > of the ModalityWorklists plugin.
> Sure. Do you think I should open a card on Trello or is the
> above a wontfix from the beginning ?
You can of course add a card, but be warned that I have currently to entirely focus, for my employer, on a revamped version of the Orthanc Client library and on the support of DICOM whole-slide imaging. Please also note that creating a plugin is really easy, that there are many examples around, and that full documentation is available : It would be cool if someone could contribute to Orthanc by developing third-party plugins besides myself.