Properties of X-rays

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  • Created by: Hope
  • Created on: 23-03-14 17:25

Properties of X-rays

X-rays are high frequency, short wavelength electromagnetic waves. (and are part of the electromagnetic spectrum)

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                                                                                         ^xrays 

Long wavelength, Low frequency&energy                    Short wavelength, High frequency&energy 

Properties of Xrays:

  • Transverse waves
  • Can cause ionisation (adding or removing electrons in atoms and molecules)
  • Affect photographic film in the same way as visible light (turning it black)
  • They are absorbed (stopped) by metal and bone
  • They are transmitted by (pass through) muscle tissue.
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Imaging using X-rays

Photographic Film 

X-rays pass through the patient’s body and into the photographic film. The film turns black where X-rays hit it. Bones absorb (stop) X-rays, so the film stays white where the bones are.

CCD's 

CCD is a charge-coupled device. Modern X-ray machines use CCDs instead of photographic film. The images are formed electronically, allowing them to be recorded and stored more easily than the images from photographic film.

CT Scans

Traditional X-rays only give a 2 dimensional image of the body, this doesnt allow you to see everything. CT scans involve taking a range of X-ray images from various positions. These are processed to make a 3d image of the body. This can be used to see different dimensions of structures in the body. 

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Ionising effect of X-rays

The ionising properties of x-rays mean they can damage the DNA in cells. Low doses of X-rays can cause cancer- but high doses can kill cancerous cells.

Cancer Treatment 

One method of treating cancer is to direct high energy X-rays at the tumours. This causes so much damage to the cancerous cells that they die. This treatment is called radiotherapy.

Precautions when using Xrays

Patients are limited to a number of x-rays so they arent exposed to too much radiation. Hospital staff are also at the risk from repeated  exposure to low levels of x-rays.

Shielded walls containing lead are built into all X-ray rooms to protect people outside the room. They routinely leave the room, or stand behind a screen containing lead, whenever X-ray machines are in use. In situations where radiographers cannot stand behind a screen, they wear lead aprons which act as a protective layer of clothing.

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