A scanner system. The system includes a mirror assembly having multiple reflective surfaces arranged to form one polygonal shape about an axis. A plurality of the multiple surfaces are each positionable to reflect radiation propagating from the source at a reflective angle and a position on the reflective surface to direct the radiation along a transmit path. When one reflective surface is so positioned, another surface is positioned to receive and reflect radiation along a detector signal path for processing. According to a related method for acquiring image data a mirror assembly is provided with multiple reflective surfaces sequentially arranged to form a polygonal shape about an axis. A beam of radiation is reflected from a first of the reflective surfaces and along a path in a first direction to a target region and a return signal propagates along the path in a second direction away from the target region. A portion of the return signal is reflected from a surface of a second of the reflective surfaces of the mirror assembly and along a path to a detector.