In which situation would a radiographer likely opt not to use a grid?

Using a grid in radiography is primarily to reduce scatter radiation, enhancing image contrast by improving the visibility of structures. A grid is most beneficial when imaging thicker body parts because scatter becomes more significant as tissue density increases.

In situations where the body part measures under 4 cm, the amount of scatter radiation produced is typically minimal. Therefore, the benefits of using a grid do not outweigh the disadvantages, as grids can introduce potential issues such as grid lines on images and require increased exposure factors (which could lead to patient dose increases) to compensate for their attenuation of primary radiation.

In this case, opting not to use a grid is a sensible choice, as the image quality can still be acceptable without it, simplifying the process and enhancing patient safety. The other options involve scenarios where grids could still be advantageous or necessary for achieving optimal image quality.