A collimator includes a panel and one or more blades. The panel defines an exit port, and the one or more blades are held between the panel and an X-ray source to cover at least a portion of the exit port. Each of the one or more blades has a primary blocking member and a secondary blocking member with material densities sufficient to block X-ray radiation. The primary blocking member shapes an X-ray beam emitted from the X-ray source. The secondary blocking member is secured in a fixed position relative to the primary blocking member between the primary blocking member and the panel to block scatter radiation from the X-ray beam from emanating through the exit port. The primary blocking member has a substantially non-planar surface facing toward the X-ray source. The secondary blocking member has a substantially planar surface facing toward the X-ray source.