In an extreme case of off-focus grid error, which of the following may result?

In an extreme case of off-focus grid error, increased brightness and quantum mottle at the edges of the image can occur. This phenomenon happens because an off-focus grid does not effectively absorb scattered radiation, leading to an uneven distribution of exposure across the image.

The edges of the image may receive a greater amount of scattered radiation compared to the centrally focused area. This excess exposure can result in a higher brightness at the image peripheries. Simultaneously, the presence of quantum mottle—an image noise resulting from insufficient x-ray photons hitting the detector—can be exacerbated in areas with uneven exposure.

Understanding this interplay between scattering, exposure distribution, and the resultant quality of the radiographic image is crucial for appropriately managing and correcting grid alignment and focus during radiography.