LAUSR

Results The percentage difference between measurements and calculations in the centre (at isocentre) of the Delta4 phantom is shown in fig 2 for 10 x 10 cm2 field configurations both for 6 MV and 15 MV. Graphs for the other investigated field sizes are similar. The percentage differences for the CT-based and simple model are fluctuating around zero, whereas the percentage differences without table and with the advanced table model are all either negative or positive and have a larger range. This means that the CT-based and simple table model are equivalent to each other and superior to the others. Gamma analysis of the prostate plans shows little variances between the different models. This can be declared by the observation in fig 2 that the differences between measurements and calculations are below 1% for full arcs.