THE OPTIMUM INTENSITIES FOR MULTIPLE STATIC MULTILEAF COLLIMATOR FIELD COMPENSATION

A method of determining the optimum beam intensities for compensation using multiple static multileaf collimator fields is presented. In thi s method a histogram of the number of beam pixels against beam intensi ty is generated for the intensity-modulated beam (IMB). The intensity of each beam to be used is chosen to minimize the mean square deviatio n between each bin in the histogram and the closest beam intensity. Th is method has been applied to sample IMBs possessing one maximum and t wo maxima. For both cases, the use of uniform beam intensity increment s is shown to be close to optimal. In the case with two maxima, the ef ficacy of irradiating both peaks simultaneously, rather than separatel y, has been studied and shown to be of potential benefit. The optimum intensities for an IMB for breast radiotherapy are also presented. (C) 1997 American Association of Physicists in Medicine.