Generation of wedge-shaped dose distributions through dynamic multileaf collimator dose delivery

Abstract

A new method of generating wedge-shaped dose distributions through dynamic multileaf collimator dose delivery, rather than computer controlled jaw motion, is presented. The method starts with the calculation of wedge-shaped beam profile for the desired wedge angle. The resultant wedge beam profile is then passed to the intensity modulated radiation therapy leaf sequence generation algorithm to create multileaf collimator segments for dose delivery. Wedge-shaped dose distributions are achieved through dynamic multileaf collimator dose delivery guided with the generated multileaf collimator segments. The method has been tested by generating wedge-shaped doses for a set of conventional (i.e. 15, 30, 45, 60 degree) wedge angles. A film dosimetry is utilized for dose distribution verification. For each dose delivery guided with multileaf collimator segments created for the indicated wedge angle, the desired wedge-shaped dose distributions are observed. It is concluded that dynamic multileaf collimator can be used to implement dynamic wedge in clinic.