Which statement correctly describes Detective Quantum Efficiency?

• A. A measure of brightness uniformity
• B. A ratio comparing input signal to noise
• C. A score describing the ability to convert remnant x-ray to high-quality image
• D. A unit of exposure measurement

Answer: (C)

Detective Quantum Efficiency describes how effectively a detector converts the remnant x-ray signal into a usable image while preserving image quality in the presence of noise. It reflects the detector’s efficiency in transferring the incoming signal into an image with good signal-to-noise, and it varies with spatial frequency. A higher DQE means you get better image quality for the same radiation dose.

That idea matches the statement describing the ability to convert remnant x-ray into a high-quality image. The other options don’t capture this signal-to-noise transfer aspect: brightness uniformity is about evenness of image brightness, not how well the detector preserves signal quality; a ratio of input signal to noise describes SNR itself, not DQE; and a unit of exposure pertains to dose, not detector efficiency.