Radiosurgery has become a widely accepted method of treating intracranial targets with a highly focused single dose of radiation. The technique allows the precise treatment of small targets through the use of stereotactic techniques. The ability to accurately focus and target tissues with both patient and gantry movements allows the production of sharp dose gradients. This permits large target doses and allows for the sparing of critical tissues which may only lie a few millimeters from the edge of the target volume. In order to carry out this technique, routine radiotherapy simulation and treatment planning must be replaced by virtual simulation and non-coplanar treatment planning. These procedures carry with them increased quality assurance responsibilities.