Evaluation of 3-D Treatment Plans Using Physical and Motorised Enhanced Dynamic Wedges.

Purpose: The treatment plans generated using physical and enhanced dynamic wedges for head and neck patients were analyzed in this study. Materials and Methods: The physical wedge filters on the Varian Clinac DHX accelerator have nominal wedge angles of 15°, 30°, 45° and 60°. These filters are made up of an alloy with steel and lead. In EDW technique no external beam modifier is used to create wedge dose profiles, instead wedged isodose profiles is created by the sweeping action of the jaw from open to closed position while the beam is on. The dose rate and jaw speed are also varied during the treatment, which is the function of selected energy, field size and wedge angle. The single Segmented Treatment Table (STT) called Golden STT is basically used for 60° wedge angle and 10°, 15°, 20°, 25°, 30° and 45° wedge effects are obtained by mixing open and wedge field intensities in a predetermined way. The conformal treatment plans of 20 head and neck patients were used in this study. For each patient, plans are generated using both physical and enhanced dynamic wedges. The dose was normalized to 100% at isocenter. The plans were compared using Dose- Volume histogram (DVH) tool. The DVH of the target and critical structures of both physical and enhanced dynamic wedge plans were analyzed. [ABSTRACT FROM AUTHOR]