Robotic Stereotaxic System based on 3D skull reconstruction to improve surgical accuracy and speed

Abstract

Neuroscience in-vivo animal studies often require injecting DNA material or fluorescent dyes into specific brain regions within the animal's skull. Currently, these types of injections or surgical procedures are done manually by skilled researchers using mechanically based stereotaxic platforms. However, alignment can be very time-consuming and prone to error due to the small size of brain targets.We developed a next generation robotic stereotaxic platform for small animals by combining a threedimensional (3D) skull profiler sub-system and a full six degree-of-freedom (6DOF) robotic platform to improve spatial accuracy and surgical speed. The 3D skull profiler is based on structure illumination in which a video projector projects a series of horizontal and vertical line patterns onto an animal skull and capture by two two-dimensional (2D) regular CCD cameras to reconstruct an accurate 3D skull surface based on geometrical triangulation. Using the reconstructed 3D skull profile, the skull can be guided and repositioned using a 6DOF robotic platform which is based on the Stewart design to precisely and accurately align a surgical tool with the intention of reaching a specific brain target. The system was evaluated using mechanical measurement techniques and the precision targeting of the platform was demonstrated using an agar brain phantom. An anesthetized Monogonal gerbil was also used for the system to target the medial nuclear of the trapezoid body (MNTB) by dye injection using a glass pipette. Fluorescence imaging of the excised brain slices confirmed the accuracy of targeting the brain nucleus. The results indicate that this new stereotaxic system can improve accuracy and speed of small-scale brain surgeries for neuroscience studies which may accelerate neuroscience discoveries and reduce the attrition rate of experimental animals.