So we took a closer look at the logfiles from the MLC controller, which seem to be a valuable source of information, this shows a small cutout. The method of analyzing these logfiles is not new, it was mentioned in MedPhys and also at the Varis user meeting some years ago. The files contain all leaf positions (where the leaves should be and where they really are during the treatment), so I was trying to use these 80 measuring devices that are already there for free in the MLC assembly - and I mean the 80 leaf motors - and calculate fluences out of these files.