Portal:Medicine/Selected article/33, 2007

An X-ray picture (radiograph), taken by Wilhelm Röntgen in 1896, of His wife's hand]] X-rays (or Röntgen rays) are a form of electromagnetic radiation with a wavelength in the range of 10 to 0.01 nanometers, corresponding to frequencies in the range 30 to 30 000 PHz (1 PHz = 1015 Hertz). X-rays are primarily used for diagnostic radiography and crystallography. X-rays are a form of ionizing radiation and as such can be dangerous. In many languages it is called Röntgen radiation after one of the first investigators of the X-rays, Wilhelm Conrad Röntgen.

The unit of measure for an X-ray is called a rem, abbreviated "r". A rem is a relatively large amount, and therefore exposure to X-rays for medical use is often measured in mrems (or millirems).

The average person living in the United States is exposed to approximately 360 mrem annually from background sources alone.

(More...)

uhiu988uoiuo