A three-dimensional phantom for providing displacement profiles for a CT table having 6 degrees of freedom includes a body having at a top face, a side face and an end face; the top face and the side face sharing a common edge; the top face and the end face sharing a common edge; and the side face and the end face sharing a common edge; wherein an angle formed by the top face and the end face is less than 90 degrees; the side face including a first isocenter mark and a first offset mark, wherein the first offset mark has an angle corresponding to the angle formed by the top face and the end face; and an isocenter marker at the isocenter of the body.