11.6 Medical uses of X-rays
What is an X-ray?
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Image of the inside of your body
Discovered over 100 years ago
A form of ionising radiation
Can be helpful
But kills living cells
Early researchers developed forms of cancer.
Why do doctors take X-ray images?
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Used by doctors and dentists
Use X-rays to see inside the body of a patient
Do not need to do an operation
Removes the chance of the patient developing
an infection.
What are X-rays?
• High energy transverse waves
• Part of the electromagnetic spectrum
Waves
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We are surrounded by waves in nature
Water waves
Sound waves
http://www.mediacollege.com/audio/01/soun
d-waves.html
• Light waves
• Seismic waves
• Electromagnetic waves
Electromagnetic waves
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Radio
Microwave
Infrared
Visible
Ultraviolet
X-rays
Gamma waves
Watch these
http://www.bbc.co.uk/learningzone/clips/theelectromagnetic-spectrum/10676.html
http://www.bbc.co.uk/learningzone/clips/usesof-electromagnetic-waves/10677.html
Waves
• Most waves need a material to travel through
• Solid, liquid, gas
• Electromagnetic waves can also travel through
a vacuum
• What is a vacuum?
Waves
• Regularly repeated disturbance that passes
through the material
• They all transfer energy from one place to
another
• But the material does not travel with the
energy.
Electromagnetic waves
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Travel through space at the speed of light
300 million m/s
X-rays are very energetic
An X-ray is a shadow picture
Light patches show bones which the X-rays
cannot pass through.
• The darker patches show places where X-rays
could pass.
What are X-rays
• High frequency electromagnetic wave
• Can pass through some materials – without
being absorbed (taken in)
• Bones and teeth absorb X-rays. (take them in)
• Doctors can see a lot of detail
• Diagnose medical conditions
• Tumours
• Chest infections
• CHEST X-RAY SHOWING
TUMOUR ON LEFT SIDE
OF THE LUNG
How are-Xray images produced?
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Photographic film behind the patient
X-ray generator in front of patient
X-rays produced
X-rays penetrate (go through) skin and muscle
X-rays absorbed (taken in) by bones and teeth
X-rays that go through the patient expose the
film.
• Film developed
• Areas not exposed are white
• Areas exposed are black
Watch this
• http://www.bbc.co.uk/learningzone/clips/xrays/4553.html
Using X-rays to diagnose conditions
• What conditions can be diagnosed using Xrays?
• What conditions cannot be diagnosed using Xrays?
Dangers of X-rays
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X-rays are ionising radiation
They can cause cancer
But risk of a few X-rays is tiny
Radiographers are at risk of receiving high doses
of radiation
• Lead (very dense) absorbs the X-rays
• Lead screen between radiographer and the
patient.
• Wear a film badge to see how much they have
been exposed to.
Key points
• Ionising radiation can treat cancer as it kills
cells
• X-rays are high energy, transverse,
electromagnetic waves
• ‘Shadow pictures’ are images of the inside of
the body, which are produced using X-rays
• Radiographers and medical professionals need
to be protected from the harmful effects of Xrays
keypoints
• http://www.bbc.co.uk/learningzone/clips/me
dical-uses-of-x-rays-the-electromagneticspectrum/1455.html