Compared to a stationary grid, what is the main advantage of using a moving grid?

The main advantage of using a moving grid is that grid lines will be blurred and not visible, resulting in a clearer image without the linear artifacts that stationary grids can introduce.

When using a stationary grid, any grid lines that cross the primary beam can appear in the final image, which can detract from the overall quality and clarity of the x-ray. In contrast, a moving grid operates by shifting during the exposure, thus minimizing the visibility of the grid lines. This motion allows for more uniform distribution of the radiation across the image receptor, which improves the diagnostic quality of the images produced.

The other aspects related to grid efficiency and image contrast are also important but relate to different factors. While moving grids do improve the quality of the image by eliminating the grid lines, their efficiency in absorbing scatter radiation or the contrast they provide is not their primary distinguishing feature compared to stationary grids. Therefore, the ability to blur the grid lines is what primarily enhances the diagnostic clarity of radiographic images.