Certain embodiments of the present invention provide a system for an electromagnetic shield assembly for use with C-arms. In an embodiment, the system may include a ring shield configured to encompass an x-ray detector. The ring shield may have a first window opening to receive x-rays. The system may also include a window shield configured to shield the first window opening of the ring shield. Certain embodiments of the present invention may provide a system for a universal navigation target. In an embodiment, the system may include a radiolucent calibration target and an electromagnetic shield. The electromagnetic shield may include a ring shield having a first window opening to receive x-rays and a window shield configured to shield the first window opening of the ring shield.