Calibration and Registration Method for Tomography-Based Laser-Guided Surgical Interventions using a 4-DOF Navigation Robot

A method for co-registering pre-surgically acquired tomographic data with a patient at time of surgical intervention is introduced. The system using this method consists of a registration element fixed to the skin of the patient at scan and intervention time, a camera, and a laser pointing device movable on a bow rail circumferencing the body of the patient. Camera and laser bow are firmly mounted and calibrated to each other. Pre-operative planning is done using the tomographic data. After moving the patient out of the gantry, the laser ray is steered to indicate position and orientation of a linear instrument (e.g. a needle) on the patient's skin. It is shown, that the achievable accuracy of the method presented in this paper is sufficient for periradicular therapy.