MRI compatible robot with calibration phantom and phantom

A medical robot for use inside a magnetic resonance imager having an axial plane defined by a vertical axis and a sagittal plane defined by the lateral axis, the medical robot being connectable to a medical instrument assembly comprising:

• a horizontal motion assembly including a horizontal motion joint, a horizontal ultrasonic motor operably connected to said horizontal motion joint and a horizontal encoder operably connected to said horizontal ultrasonic motor, wherein said horizontal ultrasonic motor and said horizontal encoder are positioned proximate to said horizontal motion joint;
• a vertical motion assembly operably connected to the horizontal motion assembly, the vertical motion assembly including a vertical motion joint, a vertical ultrasonic motor operably connected to said vertical motion joint and a vertical encoder operably connected to said vertical ultrasonic motor, wherein said vertical ultrasonic motor and said vertical encoder are positioned proximate to said vertical motion joint and the medical instrument assembly is operably connectable to one of said vertical motion joint and said horizontal motion joint;
• and
• a controller operably connected to the horizontal motion joint and the vertical motion joint;
• wherein the ultrasonic motors each has a corresponding cross section positioned in a plane selected from the group consisting of the sagittal plane and axial plane of the magnetic resonance imager.