Which of the following adjustments would likely lessen radiation dose without sacrificing image quality?

Reducing the field size directly affects the area that is exposed to radiation, which in turn minimizes the overall radiation dose to the patient. By limiting the field of view, the amount of radiation that passes through the patient is decreased while still capturing the necessary anatomical details within the smaller area. This adjustment allows for improved dose efficiency, as it focuses the radiation on the region of interest without compromising the quality of the diagnostic image.

In contrast, decreasing the distance from the tube typically increases the radiation dose to the patient due to the inverse square law, which states that the intensity of radiation is inversely proportional to the square of the distance from the source. Increasing mAs actually raises the radiation dose, as mAs (milliamperes per second) determines the quantity of radiation produced. While using lead aprons is a method of radiation protection for nearby individuals rather than a technique to reduce the dose for the patient being imaged, it does not influence the radiation exposure for the patient themselves. Thus, reducing the field size is the most effective method listed to achieve the goal of lowering radiation dose without sacrificing image quality.