The main function of the grid is to eliminate the influence of scattered rays on the film.

In medical diagnosis work, the human body’s chest is composed of gas, bone, soft tissue and other tissues with different densities. Therefore, X-ray examination for chest fluoroscopy or filming is the most common, simplest, and most direct in medical diagnosis. The clearest method of inspection. The quality of chest radiographs directly affects the diagnostic rate of X-rays. One of the main factors to improve the quality of photos is to suppress scattered X-rays, and the application of the grid is to eliminate the scattered rays emitted by the scatterer before reaching the photo. It is an effective device that directly absorbs the scattered rays. Its principle is to filter the scattered rays. The wire grid is placed between the photo and the limb, and the center line of the X-ray tube is aligned with the center of the grid plate, so that the primary X-rays emitted from the X-ray tube are parallel to the grid lead strip, and part of it passes through the lead strip When the gap reaches the photo, another part of the ray reaches the top of the lead strip and is absorbed. The scattered rays emitted by the subject cannot pass through the lead strip gap due to the angle with the lead strip, so most of them are absorbed, thereby reducing the scattering on the photo. The line volume greatly improves the contrast of the photo and improves the image quality of the photo.
According to the structure classification, the grid can be divided into:
1 Convergence grid: each lead strip is inclined to the focus, that is, the extension line of the lead is concentrated on the focus
2 Parallel grid: each lead bar is parallel to each other in the vertical plane
3Cross grid: It is composed of two layers of parallel grids, and the lead strips are 90° each other.
4Circular arc grid: It is formed by superimposing the same radius from the center outwards, tile-shaped
According to the material, it can be divided into common grid and all-metal grid.

Author：Lillian