As reported by @Hamid Khosravi.
DICOM element 0018,1111: Distance Source to Patient is not captured in dx.py. CID 10008 doesn't have such a field, but does have Distance Source to Reference Point.
The model does however have a field Distance Source to Entrance, but the attempt to populate this field (in dx.py) fails as this is not the correct name. This should instead be
dist.distance_source_to_entrance_surface = get_value_kw('DistanceSourceToPatient',dataset)