In which circumstance is a grid generally employed when radiographing?

A grid is generally employed in radiography to reduce the amount of scatter radiation that reaches the image receptor, thereby improving image quality. The primary purpose of using a grid is to enhance contrast in areas where scatter radiation is more likely to occur, which is particularly relevant when imaging large or dense body parts.

When high kilovoltage is used, the potential for increased scatter also rises, making the use of a grid beneficial for maintaining image clarity. Although the goal of a lower patient dose is important, using a grid can actually require an increase in radiation dose to compensate for the reduction in overall exposure.

In the context of radiographing thin body parts, a grid is typically not necessary because the path that the primary radiation travels is shorter, resulting in less scatter. Therefore, the use of a grid in these instances is not as effective or necessary as when imaging larger body parts or utilizing higher kilovoltage. Overall, a grid is most frequently employed when radiographing large or dense body parts, where the concerns about scatter are paramount.