Аннотация:Intensity modulated radiation therapy may be delivered via dynamic control of a multileaf collimator by defining dynamic leaf trajectories at a series of control points which are spaced at arbitrary intervals throughout an exposure. Leaves move linearly between the positions defined at the control points and hence leaf motion is a linear approximation to the planned trajectories. When many control points are used, very complex modulations can be defined accurately. If too few are used, dose errors are introduced which depend on the complexity of the modulation and the number of control points chosen. Proposed intensity modulations, of varying complexity, have been converted to trajectory plans where the number of equally spaced control points varied between 11 and 99. In each case the fluence map generated by the resulting leaf motions was computed, and this was quantitatively compared with the desired modulation by calculating the root mean square (RMS) error.
