Stereotaxic target calculation : theory and practice

Modern neuro-imaging techniques have significantly increased the accuracy of stereotactic procedures and have thereby generated a renewed interest in guided brain surgery. This paper describes the neuroradiological aspects of stereotaxic target calculation (x-, y-, z- coordinates) using the Riechert-Mundinger (Fisher) frame for computed tomography (CT). Selected cases are shown, illustrating patient positioning, CT technique, target identification and calculation. The importance of obtaining pre- and post-stereotaxic CT examinations is emphasized. Finally, future developments such as magnetic resonance (MR) guided stereotaxis and integrated functional-anatomical computer generated 3-dimensional maps, are briefly discussed.