Why does using a grid decrease exposure to the receptor?

Using a grid decreases exposure to the receptor primarily because grids absorb some of the primary beam. Grids are designed to improve image quality by reducing the amount of scatter radiation that reaches the imaging receptor. Scatter radiation occurs when x-rays interact with matter, such as tissues in the body, and instead of traveling directly to the detector, they are deflected in various directions.

By placing a grid between the patient and the receptor, it allows only the primary, straight-line x-rays to pass through while absorbing much of the scattered radiation that can degrade image quality. This selective absorption results in fewer overall x-rays reaching the receptor, which can lower the exposure necessary to produce a diagnostic image.

The choice which states that grids do not interact with x-rays is incorrect because grids are specifically designed to interact with x-rays to selectively absorb scatter. An option suggesting grids increase motion blur misunderstands the function of grids; while they help in producing clearer images, they do not contribute to motion blur themselves. Lastly, the claim that grids enhance scatter radiation contradicts their primary purpose. Grids are actually implemented to reduce the amount of scatter radiation that affects image quality, not enhance it.