Why is AEC calibration and QC essential?

• A. To increase exposure times for large patients.
• B. To allow manual control of time instead of automatic.
• C. To reduce patient dose to zero.
• D. To ensure the sensor system accurately stops exposures at the correct receptor signal, maintaining consistent image quality across patient sizes.

Answer: (D)

Consistent receptor exposure across a range of patient sizes depends on accurate automatic exposure control sensing and stopping the beam at the right moment. AEC uses detectors under the patient to measure the radiation reaching the image receptor and ends the exposure when a preset signal is reached. Calibration and quality control ensure those detectors and the related electronics respond correctly: the detectors are properly positioned, their sensitivity is accurate, and the system’s response is stable day to day and across different exam types. When calibration is up to date, variations in patient size and tissue density yield similar receptor exposure because the system adjusts to the actual attenuation and stops at the intended signal. Without calibration and QC, exposures can run too long or too short, leading to under- or overexposed images, more repeats, and higher or unnecessary patient dose.