When would a technologist lower the mAs during imaging?

Lowering the mAs, or milliampere-seconds, during imaging is typically done to reduce the radiation dose while still achieving sufficient image quality for soft tissue examinations.

Soft tissue has lower density compared to bone and dense areas, meaning it requires less exposure to produce a clear image. High mAs settings are generally used when imaging denser structures or areas that absorb more X-ray photons, as these require more radiation to penetrate effectively. Therefore, when imaging soft tissues, which do not require as much exposure, a technologist will lower the mAs to optimize patient safety while still capturing the necessary details within the soft tissue.

In contrast, imaging bone structures or dense areas typically necessitates higher mAs to ensure that the images are adequately exposed, as these areas absorb more radiation. Similarly, contrast studies, which often involve the use of contrast agents and may require specific levels of exposure to adequately visualize the contrast-filled structures, would not warrant lowering mAs.