P3.1 X-rays and ultrasound Flashcards
The wavelength of an X-ray is in the same…
…order of magnitude as the diameter of an atom
The wavelength of X-rays are…
Are X-rays ionising?
…very short.
Yes
What are four properties of X-rays?
- Affect photographic film the same way as light
- Absorbed by metal and bone
- Transmitted by soft tissue
- Wavelength in the same order of mag. as diameter of an atom
How does the property of affecting photographic film link to the use of X-rays?
It can form an image on an X-Ray plate or on a CCD
What is a CCD and what does it do?
A charge-coupled device allows the image to be formed electronically
Give an advantage of a CCD
The images are recorded and stored more easily than the images from photographic film
What materials are X-rays absorbed by?
Bone and dense materials (metals)
How does the property of being absorbed by dense materials link to the use of X-rays?
X-rays can take shadow pictures of bones to detect breaks
Give 4 uses of X-rays
DIAGNOSIS AND TREATING.
e.g. CT scans, bone fractures, dental problems, killing cancer cells,
What is a CT scan?
Computerised Tomography scans take X-ray images taken from various positions and processed to build a 3D image
X-rays are highly ionising. What can the high ionising power be used for?
Killing cancer cells in radiotherapy
What do X-rays do in a CT scan?
Detect problems with soft tissue
Give 2 precautions that should be taken when working with X-rays
Use a focused beam so as not to expose areas that aren’t being treated
Technicians or medical workers should wear film (detection) badge which measure their exposure over time do that they’re not overexposed
What happens to ultrasound waves that reach a boundary?
They’re partially reflected
From what can you determine how far away a boundary is?
Time taken for the reflections to reach the detector
