Which type of grid error results in decreased receptor exposure at the periphery of an image?

The type of grid error that results in decreased receptor exposure at the periphery of an image is indeed an off-focus error. This occurs when the x-ray tube is not positioned correctly in relation to the grid. Grids are designed to absorb scatter radiation while allowing primary beam radiation to pass through. When the x-ray beam is focused too far from the grid's focal range, specifically when it is outside this range, it leads to significant attenuation of the primary beam at the edges of the image.

In this situation, the periphery will receive less of the useful x-ray photons, leading to the appearance of decreased receptor exposure or brightness at the edges of the image, while the center may have more exposure. This characteristic is particularly crucial for diagnostic imaging, as it can compromise the quality and diagnostic value of the image.

Other types of errors, while they can also impact image quality, do not specifically result in a peripheral decrease in exposure the way off-focus errors do. Off-center errors typically cause uniform exposure changes across the image rather than localized changes, off-level errors affect overall exposure without preferentially targeting the edges, and off-angle errors result in distortion and shadowing rather than a specific decrease in exposure. Understanding these nuances helps in troubleshooting and optimizing imaging techniques