In DR systems, what does the exposure indicator (EI) represent and how should it be used to adjust technique?

• A. It measures grayscale of display; adjust window settings.
• B. It indicates detector exposure level; adjust technique to bring EI to target range.
• C. It indicates monitor brightness; adjust ambient light.
• D. It represents patient heart rate; adjust technique to steady EI.

Answer: (B)

The main idea is that the exposure indicator shows how much radiation actually reached the detector during the exposure. This numeric index is tied to how much signal the image receptor received, and it’s used to judge whether that receptor exposure falls within the optimal range for the exam. Use it to adjust technique: if the EI is below the target, increase technique (more exposure, within safety limits) to raise detector exposure; if the EI is above the target, decrease technique to lower exposure. The goal is consistent, adequate image quality while keeping patient dose in check. EI reflects detector exposure, not display grayscale, monitor brightness, or patient heart rate, and it’s not a direct measure of patient dose, though higher EI generally means higher exposure and dose.