Exact dose planning for stereotactic radiosurgery was enabled in connection with diagnostic angiography or at the end of an endovascular procedure by simply placing a stereotactic localizing box onto the head of the patient while acquiring PA and lateral angiographic views. The fiducials engraved on the localizing box enabled the appropriate images to be scaled to the stereotactic space. Regular dose planning was then performed after estimating the size of the patient's head. A prediction of the chances of obliteration and the risks of complication could then be made immediately after the en do vascular or diagnostic procedure, and further therapy could be selected much more confidently. This technique may also be used at centres without facilities for radiosurgical treatment if only the localizing box is available. The images may then be sent for evaluation to a unit with dose planning equipment. The technique is simple and involves little risk, significantly improving patient management. Digital subtraction angiography was used in this study. A correction algorithm was used to minimize the geometric distortion inherent to the digital technique.