Enable adding volume from DICOM

[ebrahimebrahim]

Hey, when we do "Add Volume", the file browser has a dropdown that includes "DICOM" as a valid format, but the window only lets you select a single file. Does that DICOM loader work? Is it expected to?

It doesn't currently work, but we should make it work.

OpenLIFU-python might only support having a single file represent a volume, but that might be just fine because once the user adds a volume from DICOM we can always write to the openlifu database as a nifti.

[ebrahimebrahim]

Actually there are two separate DICOM support issues:

• Load volume: Loads a volume into the scene. This is a Slicer operation and it should be a relatively small fix to make it support DICOM -- I think
• Add volume: This is an openlifu operation -- it doesn't load a volume into the scene but rather just adds a volume to the openlifu database using openlifu.db.Database.write_volume. It would be moe effort but not difficult to make it support dicom. We could for example add the dicom support at the SlicerOpenLIFU level, converting DICOM to nifti on the spot. Or we can make OpenLIFU-python convert dicom to nifti. Or we can make it support storing raw dicom in the database (a larger change because a volume can then consist of multiple files)

Will need to clarify one or both of these to focus on and choose an approach

[ebrahimebrahim]

Based on chat/email conversations, we want to support Add volume.

This makes this an OpenLIFU-python thing so I am moving the issue.