A waveguide for a radio frequency door like that used in a medical imaging room allows intravenous lines and electrical conduits to be inserted through the door frame without being disconnected from the patient. The waveguide includes a door frame section, and a removable, telescoping or pivoting movable member that cooperates with the door frame section to retain the conduits. The movable member is positioned away from the door frame section during insertion and removal of the conduits from the door frame section, and is positioned adjacent the door frame section when the conduits are being retained. The dimensions and materials of the waveguide are selected to achieve attenuation of electromagnetic interference.