An improved technique for comparing Gamma Knife dose-volume distributions in stereotactic radiosurgery

A function derived from the geometry of brachytherapy dose distributions is applied to stereotactic radiosurgery and an algorithm for the production o f a novel dose-volume histogram, the Anderson inverse-square shifted dose-v olume histogram (DVH), is proposed. The expected form of the function to be plotted is checked by calculating its value for single focus exposures, an d its application to clinical examples of Gamma Knife treatments described. The technique is shown to provide a valuable tool for assessing the adequa cy of radiosurgical plans and comparing and reporting dose distributions.