An apparatus for rendering X-rays visible by projecting them, in real-time, onto a screen of calcium tungstate. The technique is known as fluoroscopy, and it provides a method of being able to watch, for instance, the beating of the heart, or the movements of the intestine after the administration of a barium meal or to precisely locate anatomical targets for administration of pain relief intervention, for example to a particular spinal nerve root. (See also X-RAYS.)