Introduction to Radiography and Health and Safety Flashcards
Define an x-ray.
A type of electromagnetic radiation .
What are photons?
Parcels of energy X-rays are produced in.
What is the primary beam composed of?
Photons of xrays.
Define a radiograph.
An image made using xrays.
What is ionising radiation?
Radiation that
carries enough energy to knock electrons from atoms or molecules, thereby ionising
them.
What can ionising radiation do to living cells?
Damage them. Can die or become cancerous.
Define wavelength.
Distance between 1 wave peak and the next.
Define frequency.
The number of waves per second.
Why are the dangers of x-rays underestimated?
Invisible
* Painless
* The effects are latent
* The effects are cumulative
Define somatic effects of radiation
This is direct damage that occurs very soon after exposure
It affects rapidly dividing cells Eg skin, gut, bone marrow (+ tumour cells)
What are the clinical signs of somatic effects?
skin reddening and cracking
loss of hair
bone marrow depression
vomiting and diarrhoea - leading to dehydration
cataract formation
foetus damage
Define carcinogenic effects of radiation.
Induction of cancer due to DNA mutations.
How quickly do carcinogenic effects take to develop?
There is a latent period.
Define genetic effects of radiation.
The germ cells (sperm + ova) of breeding animals can be affected.
What can genetic effects of radiation lead to?
Infertility or abnormalities in the young.
Name two sources of radiation hazards.
Primary x-ray beam and scatter radiation.
What should happen if there is leakage from the x-ray tube head?
This should be checked by an engineer.
To be on the safe side, NEVER hold or touch the tube head during an exposure.
Explain inadequate beam filtration.
The window of the X-ray tube head contains an aluminium filter to remove ‘soft’ Xrays which contribute to the radiation hazard to the patient.
The thickness of the aluminium filter depends on the kV potential of the X-ray tube
head. This will also be checked by the engineer.
How can collimation be tested?
Place 2 coins with their edges touching - one inside the light + one in shadow on
each of the four sides of the beam
Make the exposure, and check accuracy
How should you collimate?
Collimate as tightly as possible
around the area under observation. This also improves the quality of the radiograph.
The X-ray beam size must not exceed the size of the film or cassette, therefore on a
good radiograph you should see all 4 edges.
Can a part of any person ever enter the primary beam if covered by protective clothing?
No
How is scattered radiation produced?
This is produced due to the interaction of X-rays with the patient or other matter, and
can occur in any direction. It is of hazard both to the patient and the operator.
How can you minimise the risk of scattered radiation?
o Stand as far away as possible from
the patient, at least 2m
o Collimate well
o Use lead backed cassette
o Use intensifying screens
o Wear protective clothing
What is radiation-protective clothing made out of?
Usually consists of rubber impregnated with lead.
