What field size will produce the lowest receptor exposure, assuming all other factors remain constant?

The field size that will produce the lowest receptor exposure, while keeping all other imaging factors constant, is the smaller one—specifically, the 8 in x 10 in size. This is because receptor exposure is directly influenced by the size of the field area that is being irradiated; a smaller field size will have a more limited exposure area, which means less radiation will reach the receptor.

In imaging, the radiation dose is distributed over the area of the field. Thus, when using a smaller field size, the same amount of radiation results in a higher concentration of exposure per unit area. Conversely, larger field sizes spread the same radiation over a bigger area, leading to lower receptor exposure per unit area.

As a result, while the 8 in x 10 in field size minimizes the exposure to the receptor, larger field sizes like 10 in x 12 in, 14 in x 17 in, and 24 in x 30 in would lead to increases in receptor exposure due to the wider area being exposed to the same radiation dose. This principle plays a critical role in optimizing image quality while also managing patient safety with respect to radiation exposure.