Can X-Rays Kill a Person?

The use of X-Rays in the health care field provides important diagnostic information to medical and dental professionals. However, radiation also can be dangerous. Given extensive exposure, they may cause cancer or other health risks to life. Patients have legitimate concerns about what level of exposure is safe. An understanding of the background and the typical amounts of X-Rays used in various medical procedures may alleviate at least some of these fears. With this knowledge, people can make informed judgments about the safety of specific tests.

History

• The first person to take an X-Ray picture was Wilhelm Röentgen in November 1895. Accounts differ as to whether the picture was of his wife's hand or of a key that was left on some camera film next to a cathode ray tube. If the first story is true, it happened shortly after Röentgen discovered the invisible rays by accident. He was working with the cathode ray generator invented by an Englishman, Sir Richard Crookes, two years earlier. The generator now is called a Crooke's Tube. If the second version is true, then the discovery and first picture were simultaneous. In either case, the discovery of the invisible rays was a happy accident for medicine. For his discovery, Röentgen received the Nobel Prize for physics.

Significance

• X-Rays help people in the health-related arena both in diagnosis and treatment. By allowing doctors and dentists to see the internal structure of the human body without invasive procedures, problems such as tumors, broken or misaligned bones, and developing dental problems can be studied. More accurate methods of treatment can then be designed. Along with the often life-saving properties of X-Rays, the potential has risen for increased frequencies of cancer, which can be caused by X-Ray exposure. X-Rays now also serve in attempts to prevent terrorist attacks on airplanes by scanning luggage.

Benefits

• The development of X-Rays led to more sophisticated devices that provide enhanced diagnostic capabilities. The computed or computerized tomography scan, abbreviated as CT scan, replaces the fixed X-Ray machine where the patient is between the X-Ray generator and a photographic plate with a rotating unit that circles the body. The result is a series of many computer images. The CT scan allows more detailed views of internal organs as well as bones. Where a simple X-Ray can show bones clearly and vague outlines of organs, the CT scan can illuminate detailed features of the organs.

Considerations

• The great potential for help in medical problems must be balanced by an understanding of the potential for harm from X-Rays, particularly as they have become such a basic part of medical diagnosis. Medical and dental personnel have so come to rely on X-Rays that often pictures may be taken without sufficient concern for accumulating cell damage. Also, there may be limited understanding of actual dosage patterns by those involved in giving X-Rays---the technicians.

Misconceptions

• A commonly stated opinion voiced by health workers---and doubtlessly heard at least once by ever reader--- is that a single X-Ray produces no more effect than exposure to cosmic radiation from taking cross-country airline flights.
  Radiation is measured by different units but a common one is the millirem, abbreviated mrem or the millisievert (mSv). An average airline passenger taking ten flights a year is exposed to three mrem. A chest X-Ray sends ten mrem to the bone marrow. A series of dental X-Rays sends approximately 9.4 mrems to the bone marrow but several thousand mrem to the skin. The approximate lethal dose, that is, the amount of radiation that will cause death in 50% of the people exposed to it, is 450,000 mrem. [Source: National Council on Radiation Protection and Measurements.]

Warning

• The dangers from occasional exposure to medical and dental X-Rays seem less than the benefits gained. However, concerns have been raised about the effect on DNA through increased use of CT scans, which use many times the amount of X-Rays than simple, one shot procedures. For example, a single upper gastrointestinal tract CT scan sends an amount of radiation to the body that is equivalent to 150 chest X-Rays. A full CT scan of the abdomen equates to 500 chest X-rays. [Source: European Commission, Radiation Protection Report 118, "Referral Guidelines for Imaging," 2000.] The National Academy of Sciences in 2005 found cancer risk from any one X-Ray procedure to be quite small, but continuing exposure does have a potential to increase risk. [Sources "Science Daily," October 27, 2005, accessed November 16, 2008; "Health Risks from Exposure to Low Levels of Ionizing Radiation, Board on Radiation Effects Research, National Academy of Sciences, (National Academies Press, 2005).]