Recently developed software for correction of the geometric distortion in digital subtraction angiography was tested clinically. Localization and subsequent radiosurgical treatment of intracranial arteriovenous malformations was undertaken in 60 patients. During each angiographic series, a series of grid images was also acquired. All images were transferred to a workstation where the grid images were compared to a previously stored ideal image of the grid. A distortion correction was then performed on the grid images. The same pixel-by-pixel correction was applied to the respective angiographic images. The target was outlined on corrected subtracted images on the monitor. The outlined regions of interest and reference points were transferred to another workstation for dose planning, and the treatment was subsequently executed in the Gamma Knife unit. The clinical applicability of the distortion correction program was tested and possible sources of error examined. The experience gained is being used for further development of the software and for smoother data management and reduction of the processing time.