Examining patient's thorax using X-ray tube and fluorescent screen. X-ray tube (on tripod) is set at reqauired height and patient stands directly in front of it. In front of patient, operator holds specially coated paper screen. When X-rays fall on paper, coating fluoresces, leaving as shadows those dense portions of thorax, such as bones, which absorb X-rays. Engraving, Leipzig, 1903. Many who worked with early x-rays suffered the effects of over-exposure to radiation.