A flat-panel detector is exposed with nothing between the x-ray tube and detector, what quality control test was performed?

When a flat-panel detector is exposed with nothing placed between the x-ray tube and the detector, the quality control test being performed is related to the measurement of the detector's ability to consistently produce images under the same conditions. This situation specifically aligns with the concept of repeatability, which assesses whether the system can reproduce the same results when the same conditions are applied multiple times.

Repeatability is crucial as it indicates how consistent the imaging system is and whether any variations in the outputs can be attributed to factors other than the detector's inherent characteristics. If the same exposure conditions are applied repeatedly and yield consistent results, it confirms that the detector is functioning reliably under those specific settings.

The other options touch on different aspects of quality control. Linearity assesses the detector's response to varying exposure levels, reproducibility evaluates how different operators or conditions influence the output, and spatial resolution tests the ability of the detector to distinguish fine details in the image. However, none of these directly correspond to the condition of exposing the detector without intervening objects, which is a classic setup for assessing repeatability.