What is the effect of the focus deviation of x ray grid?

The focus deviation of the x ray grid does not match the focal length is a problem often encountered with x ray grids.
The focus deviation and focal length of the x ray grid are inconsistent with the structure of the x ray grid itself. The lead bars of the convergence x ray grid are arranged in focus, and the photographic convergence line should coincide with the focus of the line, so that the original emission line The lead strips are parallel and can pass smoothly, and the direction of the scattered lines is random, and rarely coincides with the direction of the lead strips, so most of them are absorbed by the lead strips, and the obtained image has better definition.

If the X-ray tube focus and the x ray grid convergence line deviate, or the filter line is not placed at the specified focal length, the original emission line loss will inevitably occur, and the percentage of the loss is proportional to the deviation amount and the focal length difference. At the same time, there is a direct multiple relationship with the gate ratio of the x ray grid. Therefore, the filter should be placed as far as possible in the required position. However, when it is actually used in clinical practice, some deviations are unavoidable.

Author：Alina