Design of a Surgical Robot and Brain Exploration Framework for Small Animal Stereotaxy

This thesis presents the development of a computer- and robot-assisted framework for small animal stereotaxy. From a detailed analysis of stereotactic procedures on small animals, a conceptional layout of the framework is described. Two major parts are addressed. The first part presents the design of a robotic assistant for small animal stereotaxy. It provides information on the kinematic design, the construction, and the utilized components. An analytic description of the system is provided by the forward and inverse kinematics. Important issues concerning the operation such as system calibration are outlined. The second part describes the brain exploration software framework integrating the robotic assistant. Two subareas of brain exploration are elaborated on. First, a basic stereotactic control framework which provides planning, registration, and insertion control modalities is presented. Second, the technique of Optical Coherence Tomography (OCT) imaging is set into the context of brain imaging and optical brain exploration. The resulting computer- and robot-assisted stereotactic framework is then tested with respect to its performance in a testbed setup and in the real surgical scenario. First, the mechanical positioning accuracy is analyzed. Second, the framework is applied to two future applications in the context of brain exploration: robot-assisted microelectrode recordings and robot-assisted intracranial imaging using OCT. Concepts for data analysis pointing towards electrophysiological and optical brain mapping are introduced and evaluated based on the acquired data. Arising in the context of OCT imaging, two methods of image segmentation and filtering adapted to OCT images are presented. Analyzing the mechanical positioning accuracy shows that the presented framework allows for precise small animal stereotaxy. Results of the electrophysiological and optical data analysis support the idea of robot-assisted brain mapping via characteristic features of certain areas. This, in turn, gives rise to the idea of near field navigation in the vicinity of the probe tip, a novel navigation modality. In summary, the resulting system offers new alternatives for brain research on the small animal model.