Figure 3.

(a) Isodose distributions for an eight‐lesion case. Three lesions received 21 Gy and five lesions received 18 Gy. The total tumor volume was 15.4 cm³. (b) Two isocenters were used with five arcs on each isocenter. The couch angles for both isocenters were the same: 0, 0, 40, 90, and 330. The collimator example is for one arc in the superior isocenter treating three lesions. The collimator for each arc was manually selected with the goal of minimizing situations in which there were two targets in the same leaf track in order to minimize excess dose to the brain.