Load RT tags for DICOM series as JSON in DICOM proxy environment

[toskrip]

Sadly this code does not seem to trigger CMOVE from storage nodes to proxy local storage:

dcm = newdicomobject();
readdicom(dcm, stuid .. '\\' .. seuid .. '\\' .. souid);

When this fails, it is better to try to explicitly fetch the SOPInstance with CMOVE before we try to readdicom again.

Note: CMOVE from local to local on DICOM proxy will pick it up from storage nodes.