What is the purpose of a QA phantom in DR imaging, and which metric is commonly evaluated with it?

• A. To calibrate monitor luminance
• B. To measure patient dose
• C. To assess image quality and system performance; metrics include low-contrast detectability and spatial resolution
• D. To schedule imaging

Answer: (C)

In DR imaging, a QA phantom provides a standardized test object to probe how the entire imaging chain performs under controlled conditions. It helps gauge image quality and overall system performance, so you can detect changes over time and ensure the captured images remain diagnostically useful. The metrics most commonly looked at with a QA phantom are low-contrast detectability—how well small, subtly differing structures can be seen—and spatial resolution, which measures the system’s ability to distinguish fine detail. These two together give a practical sense of how well the detector, image processing, and acquisition parameters are supporting diagnostic work. Calibrating monitor luminance, measuring patient dose, or scheduling imaging are separate activities and not the primary purpose of a QA phantom in this context.