Introduction: Stereotactic procedures targeting intracranial structures are common neurosurgical procedures and include needle biopsies, placement of DBS electrodes, laser ablation of metastatic lesions, or hippocampal laser ablation for epilepsy treatment. Navigation systems rely on preoperative imaging, affecting the accuracy due to shifts in the brain after the dural opening. This system adds real time validation of the target[1-10] . We report the results of feasibility and accuracy of the MRI-safe robot for intracranial stereotactic procedures with real time MRI imaging in a skull phantom.

Methods: A 3-degree of freedom (DoF) MR-safe robotic system [14] that is electricity free, is actuated by pneumatic motors[15], uses light for the position sensors, and does not include any conductive, metallic, and magnetic materials was used. The 18G needle is manually inserted through the guide and the depth of the needle is set by a 1-DoF needle depth driver after orientation. The robot was fixed to the table, and the mockup was fixed to the head holder. MR image set was acquired. Targets were selected in the images relative to the robot. After each targeting, additional images were scanned for validation.

Results: The robot was mounted successfully in the arm of the Mayfield cranial fixation system (Figure 1) in a way that if perfectly fit in the bore of the intraoperative MRI (Figure 2). Points in the intracranial grid in the skull phantom were chosen as targets after MRI. The robot was aimed at the coordinates set in the MRI images and the needle was placed intracranially (Figure 3). Targeting accuracy was 1.6 mm and precision was 0.81mm with 12 trials.

Conclusions: We demonstrate the feasibility of the use of the MRI compatible robot for Stereotactic procedures with real time imaging. We also demonstrate accuracy of this robotic-assisted procedure when targeting pre-determined locations based on real-time imaging.

Patient Care: It will improve accuracy and precision of stereotactic procedures, both frame-based and frameless.

Learning Objectives: To demonstrate the feasibility and accuracy of the use of an MRI-safe robot for stereotactic intracranial procedures.

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