The invention designs the segmented short-arc VMAT plan, modified from the original long-arc VMAT, to fit the breath-hold interval. The modified VMAT of the invention has the advantages of its applicability to different planning systems for variously long arcs and its preprogrammed arc segmentation for summated dose consistency. Using segmented short-arc modification from the original long-arc VMAT plan is accurate for dose planning and delivery, as well as tolerable for breath-hold VMAT.
