As a general rule, when should a grid be employed in radiography?

In radiography, the use of a grid is primarily aimed at reducing scatter radiation that can degrade image quality. As part thickness increases, the amount of scatter radiation also increases, leading to a greater likelihood of image fog and reduced contrast.

A grid is typically recommended when the part thickness exceeds 12 cm. At this thickness, the scatter radiation produced during exposure becomes significant enough that it can adversely affect the diagnostic quality of the radiographic image. By employing a grid, radiographers can improve image quality by allowing only the direct, useful x-rays to reach the image receptor while filtering out much of the scatter radiation.

Using a grid at this thickness helps to maintain the visibility of the anatomical structures being imaged and enhances the overall diagnostic efficacy of the radiographic examination. Therefore, understanding the appropriate circumstances in which to use a grid is crucial for producing high-quality radiographs.