X-rays in Medicine Flashcards
Why can x-rays damage living cells?
Because they are ionising
Describe the frequency of x-rays
High-frequency
What kind of waves are x-rays?
SHORT wavelength ELECTROMAGNETIC waves
What is the wavelength of x-rays roughly the same size as/ how short are they?
The diameter of an atom
What material are x-rays transmitted from?
a) healthy tissue (i.e. flesh)
b) denser materials (i.e. bones or metal)
a) healthy tissue
What material are x-rays absorbed by?
a) healthy tissue (i.e. flesh)
b) denser materials (i.e. bones or metal)
b) denser materials
Name 2 ‘denser materials’
Bones
Metal
What does ‘x-rays are transmitted by healthy tissue’ mean?
X-rays pass THROUGH healthy tissue
Why can x-rays be used to take photographs?
Because they affect photographic film in the same way as visible (normal) light
Name 2 medical conditions that x-ray photographs can be used to diagnose
- Bone fractures
2. Dental problems
On an x-ray, are the brighter bits where:
a) fewer
or
b) more
x-rays have passed through the material?
a) fewer
The plate that the x-rays hit starts off white, and the electrons react with it to turn it darker.
Do x-rays produce
a) positive
or
b) negative
images?
b) negative
How can x-rays be formed, and using what?
Electronically, using charge-coupled devices (CCDs)
What are CCDs?
Silicon chips about the size of a postage stamp, divided into a grid of millions of identical pixels
How do CCDs work?
They detect x-rays and produce electromagnetic signals which are used to form high resolution images.
Where else are CCDs used?
In digital cameras
What other initial-ism beginning with ‘C’ are x-rays used in?
CCT scans
What does ‘CT’ stand for?
Computerised axial tomography
What do CT scans do?
Take HIGH RESOLUTION IMAGES of soft and hard tissue
What can be done with the images taken using a CT scan?
Multiple 2D CT scans can be put together to make a 3D image of the inside of the body
Describe the step-by-step process of taking a CT scan
- The patient is put inside the cylindrical scanner.
- An X-ray beam is fired through the body from an X-ray tube and picked up by detectors on the opposite side.
- The X-ray tube and detectors are rotated during the scan.
- A computer interprets the signals from the detectors to form an image of a two-dimensional slice through the body.
- Multiple two-dimensional CT scans can be put together to make a three-dimensional image of the inside of the body.
