The use of PortalVision for the patient setup verification can lead to a significant extra dose, which shouldn't be there and we are still looking for a solution to this problem. Although only 3 to 4 MU are needed for an image in the fast readout mode on the PV, this adds up to about 5% of extra dose to the target, because the ports are acquired every day. And the DVH of the OAR, they may really get worse. Maybe my collegue Helmut Simmel will show you some slides tomorrow. The idea of subtracting dose pedestals from a modulated field and using this CIAO field for verification would avoid this problem. I'm sure this will work in the next CadPlan version.