Intraoperative calibration of the Patil stereotactic system during computed tomography (CT) guided stereotactic procedures - A technical note

A method for intraoperative calibration of the Patil stereotactic system is described. After adjusting the z and y coordinates, a marker is placed in the pivot block and a CT scan is obtained. The presence of the marker in the indicator block on the same horizontal line as the target, on the image of the target, would indicate that the y and z coordinates adjustments are accurate. After the arc is attached with the x coordinate adjusted, a CT scan is obtained with the arc vertical and the probe holder at zero angle (from the vertical) position. The presence of the middle of the probe holder in the same vertical line as the target would indicate accurate x coordinate adjustment. This technique, which can be applied also to other stereotactic systems, allows the surgeon to check not only the accuracy of the system but also the accuracy of the procedure prior to inserting the probe into the brain.