Wedge filters for megavoltage Roentgen ray beams

The aim of this investigation, to construct a range of fixed wedge filters and to simulate these with a motorized wedge, led to the derivation of 5 equations. These equations can be used to construct and test a consistent set of fixed wedge filters, eliminating elaborate trial and error experiments. The fixed wedge filters already in existence for the Philips SL75-10 and 5L75-20 linear accelerators fitted these equations rather well. After adapting the motorized wedge of the SL75-14 according to these equations, it simulated the fixed wedges accurately. (orig.)