What is the primary function of a grid on an x-ray table?

The primary function of a grid on an x-ray table is to prevent scatter radiation from reaching the film. When x-rays are produced, not all of them travel in a straight path toward the film; some are scattered by the tissues in the patient's body. This scatter radiation can degrade the quality of the x-ray image, leading to decreased contrast and clarity.

Grids are designed to allow primarily straight, unscattered x-rays to pass through while absorbing scattered radiation, thereby enhancing the overall quality of the image. As a result, images taken with grids generally show better contrast and detail, which is essential for accurate diagnosis.

Other options may reference functions related to radiation and imaging but do not describe the true role of a grid in the context of x-ray imaging. The grid does not prevent primary radiation from reaching the film, as its purpose is specifically to allow primary radiation while minimizing scatter effects. Similarly, it does not provide a measurement scale; that's typically done using specialized tools or software. Grids are also not used for protecting the film from light because x-ray film is sensitive to radiation, not visible light.