A medical display is a computer screen made for reading medical images, calibrated so that the faintest shadows in an X-ray or a mammogram can be seen. It is also called a diagnostic display, or a radiology monitor. Radiologists read on it because an ordinary office monitor can hide the small differences in grey that matter.
An X-ray image is a picture in shades of grey. A small tumour or a hairline fracture may differ from the tissue around it by only a few shades. A medical display does three things that an office monitor does not. First, it is brighter, so the eye can tell more shades apart. Second, it is calibrated to the DICOM grey-scale standard. This standard sets how bright each shade of grey must be, so that each step from one shade to the next is equally visible to the human eye. Third, it stays calibrated. Every screen grows dimmer with age, so a sensor built into the display measures the screen regularly and corrects it.
Consider a breast screening centre in Mangaluru. Mammograms are X-rays of the breast. Early breast cancer can show up on them as tiny specks of calcium, less than half a millimetre across. The centre reads mammograms on a 5-megapixel display, which shows about 50 lakh pixels, at a brightness of about 1,000 candelas per square metre. An office monitor typically gives about 250. Every morning, before the first reading, the display's sensor checks its brightness and its grey steps. One morning, it finds that the brightness has dropped by 8%. It corrects itself and records the change in a log. The centre keeps these logs to show inspectors that every mammogram was read on a calibrated screen.
Different images need different screens. Mammograms need the highest resolution and brightness. Chest X-rays and CT scans are usually read on 2- or 3-megapixel screens. Colour displays are used for ultrasound, for 3D medical imaging and for slides from a digital pathology scanner.
The display shows what the PACS and imaging AI platform sends to it, including the marks added by AI radiology models. The quality of the picture depends on every step before the screen, from the scanner's image reconstruction onwards. But if the screen itself is wrong, a faint finding can still be missed. The company that makes these displays also makes video walls and projectors for control rooms and cinemas.