Now I want to make an excursion to an effect we noticed since the very first DMLC treatment. During sliding window delivery, dose rate sometimes (or most of the time) is not stable. With our equipment, we measured these curves for the dose rate as a function of time, for a static treatment and for a sliding window treatment. The reason for this is that the beam is shut off whenever one of the leafs is deviating from its planned trajectory by more than a certain amount for instance, which is called a beam hold. Although there are other reasons for this behavior, the most common reason for beam holds seems to be the movement of closed leaf pairs. When you compare these curves, you already see the main consequence: you lose a lot of time. It will take much longer to deliver a certain dose with this dose rate than with this one. You may ask: how can you measure such a curve during a sliding window treatment. Well, actually, we measured complete beam profiles with a simple trick.