Read the following passage.
A. The story of medical X-rays began on the evening of November 8, 1895. Wilhelm Röntgen was studying electric currents passing through gas at very low pressure. Although his tube was sealed inside thick black card, a screen coated with barium platinocyanide began to glow as far as two metres away. He found that objects of different thickness let the rays through by different amounts, and he recorded an image of his wife's hand that showed the shadows of her bones and of a ring. Because the nature of the rays was unknown, he called them X-rays.
B. An ordinary X-ray picture, called radiography, is made by passing a beam through the body. Internal structures absorb or scatter part of the beam, and the pattern that remains reaches a detector, such as film or a computer screen. In radiography a single image is recorded for later study, and mammography is a special kind of radiography used for the breasts. Fluoroscopy instead shows a continuous image on a monitor, so staff can follow a procedure or a contrast dye in real time. X-ray exams help diagnose disease without pain and guide doctors as they place devices such as stents inside the body.
C. The invention of computed tomography, or CT, was another major advance. In a CT scan, the detector circles the patient while many X-ray images are taken, and a computer turns them into cross-sectional slices of organs and tissues. Because each CT image is built from many separate projections, the exam gives a higher dose than conventional radiography. Typical organ doses are about 0.01 millisieverts for a dental X-ray, 0.1 for a chest X-ray and 10 for an adult abdominal CT. Medical procedures account for roughly 40 per cent of an average person's yearly radiation dose.
D. X-rays are ionizing radiation, which carries enough energy to damage DNA. This brings a small increase in the chance of developing cancer later in life. The lifetime risk grows with the dose and the number of exams, and it is larger for people who are X-rayed when young, so extra care is taken with children and pregnant patients. Doctors are advised to order an exam only when it is needed, to consider options that use less or no radiation, such as ultrasound or MRI, and to check a patient's imaging history to avoid repeating a test. Skin reddening and other tissue effects are rare in ordinary exams but can follow long, complex fluoroscopy procedures.
E. Not given in any of the above paragraphs.
Decide which paragraph, A to D, has the information given in each statement below. Select E if the information is not given in any of the paragraphs.