DQE
Detective Quantum Efficiency — measure of how efficiently an X-ray detector converts incoming photons into useful signal. Expressed as a fraction (0 to 1) at a given spatial frequency; higher DQE = better image quality at the same dose. The canonical headline metric for comparing flat-panel detectors across vendors and generations.
Why it matters to buyers: Higher DQE means lower dose for equivalent image quality — the practical buyer-evaluation metric when comparing flat-panel detectors. Mammography detectors are particularly sensitive to DQE because the low-energy spectrum and dense-tissue penetration challenges combine to make detector efficiency clinically visible. Vendor data-sheet DQE curves should be evaluated at clinically relevant spatial frequencies, not peak.
Why it matters to engineers: DQE degrades as panels age. Amorphous selenium detectors (Hologic mammography, some DR) age faster than CsI on a-Si — selenium-panel useful life is 5–9 years on 2009+ panels, ~3 years on earlier. Annual physicist phantom imaging tracks DQE-equivalent metrics; clinical-image quality complaints often correlate with DQE drift before they become visible to the radiologist.