How does automatic exposure control (AEC) contribute to dose optimization, and what are common limitations?

How does automatic exposure control (AEC) contribute to dose optimization, and what are common limitations?

• A. AEC terminates exposure to achieve desired optical density, reducing variability; limitations include mis-positioned anatomy, atypical patient size, and motion artifacts.
• B. AEC prolongs exposure for better penetration; limitations: always overexpose.
• C. AEC changes beam quality; limitations: increases patient dose always.
• D. AEC requires manual exposure time selection; limitations: not accurate for small patients.

Answer: (A)