A device is described which allows employ of CT data in conjunction to the Talairach frame for biopsy and other fine localization procedures. A series of new accessory parts allows reversible exact placement of the patient head in the same relative position to the reference system both in the stereotactic frame and the CT machine. No modification has been introduced in the standard Talairach head-holder, preserving its features of simplicity and versatility without need for introduction of new stereotactic methodologies or new computer programs.