X-ray grids are devices used to remove scattered radiation from radiographic images. They consist of alternating strips of lead and transparent material. Grids work by absorbing most of the multidirectional scattered radiation while allowing the directional primary radiation to pass through. Grid performance is evaluated based on primary transmission, Bucky factor, and contrast improvement factor. Proper grid selection and positioning are important to avoid grid cutoff and increased patient radiation dose. Moving grids eliminate grid line artifacts but have some disadvantages.