AN OPTIMIZED LEAF-SETTING ALGORITHM FOR BEAM INTENSITY MODULATION USING DYNAMIC MULTILEAF COLLIMATORS

A leaf-setting algorithm is developed for generating arbitrary beam in tensity profiles in discrete levels using dynamic multileaf collimator s (DMLCs). The algorithm starts with the algebraic expression for the area under the beam profile. It is shown that the coefficients in this expression can be transformed into the specifications for the leaf-se tting sequence. It is proven that the algorithm optimizes beam deliver y time and total monitor units for the DMLC leaf setting for intensity modulated radiotherapy (IMRT). The algorithm is demonstrated to be ap plicable to both the 'step-and-shoot' and 'dynamic' type of beam deliv ery. The graphical interpretation and numerical implementation scheme of the algorithm is illustrated using a simplified example.