We describe a computer program which facilitates the analysis of a series of C.T. scans made while a stereotaxic frame is fixed to the patient. The program has 2 modes of operation: a) The operator may select a region and determine the three-dimensional frame coordinate. b) The operator may select a set of frame coordinates and have the computer program display these at the appropriate sites on the C.T. scans. It these sites are the positions of depth electrodes, then a recording of the epileptic spike activity may be displayed at the appropriate sites on the scans.