Abstract: Apparatus for use with a C-arm type x-ray unit (10) to locate and center an x-ray target area. The unit has an x-ray emitter (20) located at one end of a C-arm (50) and an x-ray receptor located at the other end of the C-arm. A ring-shaped band (45) adjustably fits around an outer end of the x-ray receptor. A first laser light source (90) and a second laser light source (100) are carried on the band in a predetermined orientation to each other. The laser light sources each project a fan shaped laser light into the target area between the x-ray emitter and the x-ray receptor. The beams are adjusted to determine a center of the target area through which x-rays are propagated when a patient is positioned in the x-ray unit for a procedure to be performed.