Which adjustment should be made to technical factors when using negative contrast media agents?

When using negative contrast media agents, the appropriate adjustment to technical factors is to decrease kVp. Negative contrast media, such as air or gas, creates a contrast against the surrounding tissues primarily by reducing the attenuation of the x-ray beam. These agents are less dense than the surrounding tissues, which results in them appearing darker on the radiograph.

Decreasing the kVp helps maintain image quality by increasing the contrast between the negative contrast material and the adjacent structures, as lower energy x-rays are less likely to penetrate through the less dense negative contrast and more likely to be attenuated by denser tissues. This results in a more pronounced distinction on imaging, enhancing the clarity of the structures being examined.

In contrast, increasing kVp might result in excessive penetration, diminishing the visibility of the negative contrast agent. Adjusting mAs is also related to the quantity of radiation but does not specifically address the unique interaction that occurs with negative contrast media in terms of image contrast and quality.