An imaging system is provided. The imaging system includes an additively manufactured three-dimensional (3D) collimator manufactured out of one or more materials, the one or more materials comprise a metal, and the additively manufactured (3D) collimator is configured to provide collimation on a beam emitted from an X-ray source of the imaging system and a coating disposed over surfaces of the additively manufactured 3D collimator, wherein the coating is configured to keep metal particles from leaking from the additively manufactured 3D collimator.