EM waves/ travel at speed of light/ travel in a vacuum/ can cause ionisation/ wavelength of about 10'-10m/ high energy photons
1 of 15
Describe the production of X-rays
cathode to anode/ electrons accelerated through high voltage towards target metal when they smash into it they decelerate and small amount of the KE is converted into X-rays
2 of 15
How is the production of X-rays maximised?
good vacuum/ cathode heated to increase output/ anode shaped to beam focused/ tube is surrounded by lead shielding
3 of 15
Name the ways in which X-rays interact with matter
Photoelectric effect/ compton scattering/ pair production
4 of 15
Describe the X-ray photoelectric effect
photon disappears and its energy is used to eject an electron from he target metal (low energy photons)
5 of 15
Describe X-ray compton scattering
mid energy photon/ collides with orbital electron/ electron ejected only absorbing some energy form photon/ scattered photon leaves at different angle
6 of 15
Describe X-ray pair production
high energy/ interacts with nucleus/ electron-positron pair released/ when position annihilated by electron, two identical low energy photons produced
7 of 15
Define intensity, what is it's unit?
power per cross-sectional unit area, Wm'-2
8 of 15
Describe the intensity of a X-ray as it travels through a medium
inverse square law/ decreases in intensity as it interacts with materials atoms/
9 of 15
Describe the use of X-rays in imaging internal body structures and the use of image intensifiers
attenuated (ABSORBED AN SCATTERED) by different amounts by different mediums/ different intensities at detector form image/ X-rays collimated to have a parallel beam with constant I
10 of 15
Describe the use of contrast mediums
ie barium makes soft tissue more visible/ patient swallows liquid high in barium as it will readily absorb rays/ coats the internal wall of instant tract enabling its outline to be seen
11 of 15
What is a CAT scanner?
computerised axial tomography/ produce 2D image of a slice through the body/ can also produce 3D/ X-ray beam rates around the body and is picked up by thousands of detectors
12 of 15
Describe the operation of a CAT scanner
...
13 of 15
What are the advantages of CAT scans?
much higher quality than X-rays as no overlap/ can produce 3D images/ can distinguish between different tissues
14 of 15
What are the disadvantages of X-rays and CAT scans
both result in patient having a high dose of radiation
15 of 15
Other cards in this set
Card 2
Front
Describe the production of X-rays
Back
cathode to anode/ electrons accelerated through high voltage towards target metal when they smash into it they decelerate and small amount of the KE is converted into X-rays
Card 3
Front
How is the production of X-rays maximised?
Back
Card 4
Front
Name the ways in which X-rays interact with matter
Comments
No comments have yet been made