The present invention presents an apparatus and methods to stereotactically guide and automatically insert an invasive tubular device to a tissue object of a living body. The apparatus comprises a stereotactic positioning assembly and a powered propulsion assembly that controllably drives an invasive tubular device in and out of a tissue object. The stereotactic positioning assembly encloses an ultrasound transducer to visualize and aim at the tissue object, and adjusts an insertion angle of the invasive tubular device coupled with the powered propulsion assembly.