9. Display screens

Display screens are a subject in their own right, not specific to X-ray imaging, but how can we talk about image quality without saying a few words? The successor to CRTs, the current technology is that of LCDs, the same as that used for TVs, but devices intended for the medical imaging market are manufactured on dedicated lines because their performance is superior in terms of contrast, luminance calibration quality and resolution. Compared to CRTs, medical LCDs are brighter and offer better resolution, but they require frontal viewing, and blacks are less intense. We're not interested in the technologies themselves, but in the parameters that characterize them.

The most important is luminance, i.e. the luminous intensity emitted towards the eye per unit screen area (Cd/m ² ). Luminous intensity (candela: Cd) is itself...