Intracranial tumor biopsy--CT-guided stereotactic surgery.

A modification of Gildenberg's technique for brain tumor biopsy is described. Marking the light beam of the gantry on the scalp with a pencil, when the lesion appears on the screen, no ScoutView is necessary. With radiopaque marks on the drawn lines, the levels of the slice are transferred to a lateral conventional X-ray, for calculation of the 'Z' coordinate. 'X' and 'Y' coordinates are determined on the CT scanner.