Which feature is a CT dose optimization measure that automatically adjusts exposure?

• A. Lower mA
• B. Automatic exposure control
• C. Iterative reconstruction
• D. Shielding

Answer: (B)

Automatic exposure control modulates the tube current automatically during the scan to optimize dose while preserving image quality. It continuously adjusts the milliampere (mA) according to how much the patient attenuates the x-ray beam, using detectors to guide the changes in real time. This means thicker or denser regions receive more exposure, while thinner areas use less, keeping the overall dose as low as possible without sacrificing diagnostic accuracy. Lowering mA manually doesn’t adapt to changing anatomy during the rotation and can risk underexposure in some areas. Iterative reconstruction helps maintain image quality at lower doses but doesn’t auto-adjust exposure during acquisition, and shielding reduces dose by blocking beam rather than changing exposure in real time.