What effect do grids have in X-ray systems?

Grids in X-ray systems are designed to improve image quality by enhancing contrast, which directly contributes to the visibility of structures within the imaging field. They accomplish this by allowing only the primary X-rays that travel in a straight line from the source to the detector to reach the image receptor, while absorbing scattered radiation. This scatter typically reduces image quality by creating a fogged or blurred appearance over the area of interest.

As a result, while grids can improve contrast and hence image quality, they also lead to an increase in patient dose because they require higher exposure levels to compensate for the reduced amount of reaching the image receptor due to the absorption of scattered radiation. Hence, the correct answer highlights this dual effect of grids: increasing image quality through enhanced contrast, which in turn results in a higher patient dose due to the need for increased exposure to achieve optimal imaging conditions.