The present invention presents an apparatus and methods to guide insertion of invasive devices to a tissue target of a living body. The apparatus comprises a positioning guide control assembly and a positioning guide assembly that is operably detachable from the control assembly, and rotationally adjustable and lockable. The positioning guide control assembly releasably houses a ultrasound transducer head and measures an insertion length and an insertion angle of an invasive device placed in the positioning guide assembly to reach the tissue target.