I have downloaded SlicerRT and GelDosimetry to analyse a .vff file. Although, I couldn’t import these files. It doesn’t show nothing when I click to import.
Can you check if in the latest Slicer preview with SlicerRT installed the same thing happens? Don’t use Gel Dosimetry just drag&drop the VFF file onto Slicer.
If the same errors happen, then probably your VFF file is a different version of the format or some fields are omitted, in which case some changes will be needed in the reader code.
How did you create this file? With what software and which version? Can you upload a sample somewhere (dropbox, onedrive, gdrive) and post the link here?