Helical Volumetric Modulated Arc Therapy for Treatment of Craniospinal Axis

A continuous helical VMAT plan provides comparable dose quality to a plan with separate VMAT arcs. Comparable quality is also produced by an alternating helical plan, provided the pitch is chosen appropriately. Alternating helical plans have been delivered and verified successfully. Alternating helical delivery offers the ultimate delivery efficiency for intensity-modulated radiotherapy for the craniospinal axis.