An adaptor to the Leksell stereotaxic instrument for digital coordinate determination in radiography.

Special perspex adaptors with radiopaque reference structures have been constructed to fit to the Leksell stereotaxic instrument. These structures are visualized on X-ray film in a radiographic examination like angiography or encephalography. The films obtained in two projections at arbitrary angles and focus-film-distances are placed on a digitizing table for the determination of the stereotaxic coordinates of selected targets. The reference structures and the targets are marked with a cursor whereupon a desk top computer performs the calculation of the stereotaxic coordinates. The system allows a rapid, simple and accurate coordinate determination in stereotaxic radiography using the Leksell stereotaxic instrument.