What does exposure index accuracy QC ensure?

• A. The Displayed Exposure Index Value Corresponds to the Actual Dose to the Detector
• B. It Controls Patient Positioning
• C. It Calibrates the Tube Current
• D. It Measures Patient Dose

Answer: (A)

Exposure index accuracy QC ensures that the value shown for the exposure index matches the actual amount of radiation that reached the detector during the exposure. This alignment is crucial because clinicians rely on the exposure index to judge whether the detector has been properly exposed and to guide technique adjustments for consistent image quality and dose management. If the displayed index doesn’t reflect the true detector dose, it undermines the ability to compare images over time or across systems and can lead to under- or overexposure.

This topic isn’t about where the patient is positioned, which is a positioning/marker QA concern. It also isn’t about calibrating the tube current, which relates to the X-ray generator’s output settings (mA, exposure time) or automatic exposure control calibration. And it isn’t a direct measure of patient dose—the exposure index is a surrogate for detector exposure, not a direct patient dose measurement.