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X-rays are high-energy electromagnetic waves with small wavelengths that can pass through many materials. They are used in imaging and medical physics.
X-rays are electromagnetic waves that have wavelengths varying between 0.01 and 10 nanometres (nm). This means that the frequency and energy of these waves are high. In fact, they are high enough for x-ray radiation to be a type of ionising radiation.
Figure 1. Electromagnetic spectrum. Rosenfeld Media, Flickr (CC BY-NC-SA 2.0).
X-rays are used in medical physics for x-ray imaging. This imaging technique uses a small amount of controlled radiation to produce images of the human body’s interior.
Because various organs absorb radiation differently, images reveal different areas of our body in either black or white.
When a negatively charged electrode is heated, it causes the electrons to be emitted from it, which produces energy. In x-ray imaging, this energy is directed towards a metal plate at high velocity. When the energy collides with the atoms in the plate, x-rays are created.
Figure 2. An x-ray machine. David Jackmanson, Flickr (CC BY-NC-SA 2.0).
The process begins with the patient lying down on or standing up in front of a cassette. This cassette includes a film that is exposed to the x-ray wave. First, the x-ray wave enters the body, passing through organs, muscles, and bones. As the soft tissue cannot absorb the electromagnetic wave, it passes through and leaves the film under or behind the patient exposed, which leads to these areas appearing in black in the final image.
The bones and hard tissues absorb the electromagnetic x-ray wave so it cannot get through to the film as easily, which makes these areas appear in light grey or white in the image.
Figure 3. A chest x-ray scan. Yale Rosen, Flickr (CC BY-NC-SA 2.0).
X-ray imaging has applications in medical, dental, and industrial fields. Most of these applications are based on the x-ray’s ability to pass through matter. In medical physics, x-ray imaging is used for a variety of purposes, such as getting an image of broken bones, swallowed objects, lung infections, or damage to bones from arthritis. X-rays are also used with CT scanners to help achieve a layer-by-layer image.
In industry, x-ray imaging can help to analyse paintings to reveal their age or underlying brushstroke methods to identify or verify the artist.
Another common use of x-ray imaging is to scan passengers or luggage at airports or malls. When used for luggage, the machine has a detector that detects the x-rays after they pass through the object. The x-rays are then sent through a filter, which filters out the lower-energy x-rays while the high-energy x-rays are detected by a second detector. A computer compares the data yielded by the two detectors to better depict low-energy items, such as most biological compounds.
Since different objects absorb different amounts of x-rays, these differences can be seen on the screen used by the operator. There are three primary categories depending on the spectrum of energy that passes through the object: organic, inorganic, and metal.
Figure 4. X-ray imaging used in an airport luggage scanner. Wayan Vota, Flickr (CC BY-NC-SA 2.0).
There are three x-ray imaging techniques used for a variety of purposes. They are: x-ray fluorescence spectrometry, particle-induced x-ray emission (PIXE) spectrometry, and x-ray diffraction.
The three techniques for x-ray imaging in materials and chemistry sampling are x-ray fluorescence spectrometry, particle-induced x-ray emission (PIXE) spectrometry, and x-ray diffraction (XRD).
Some of the common applications of x-ray imaging include scanning the human body for fractured bones, ingested objects, arthritis-related bone deterioration, and lung infections; scanning passengers or luggage at airports or malls; and analysing paintings.
In the process of x-ray imaging in medical fields, the x-ray wave enters the body, passing through organs and muscles. As the soft tissue cannot absorb electromagnetic waves, they pass through, leaving the film under or behind the patient exposed, which leads to these areas appearing in black in the image. Bones and hard tissue, which absorb the electromagnetic x-ray wave, by contrast, appear in light grey or white.
X-ray imaging is done in order to create images of the interior of the human body. It is mostly done for the purpose of getting a view of fractured bones, arthritis-related bone deterioration, ingested objects, and lung infections.
First, the x-ray wave enters the body, passing through organs and muscles. As the soft tissue cannot absorb electromagnetic waves, they pass through, leaving the film under or behind the patient exposed, which leads to these areas appearing in black in the final image. The bones and hard tissues, by contrast, absorb the electromagnetic x-ray wave so it cannot get through to the film as easily, which makes these areas appear in light grey or white in the image.
The varying reduction of the x-ray beam inside a patient’s body generates a picture. Increased reduction of objects cast shadows. An object’s picture contrast relies on its x-ray beam reduction.
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