Diagnostic Aids Flashcards
What is the tungsten?
Used as the filament and target as it has a high atomic number therefore a high number of electrons and also a high melting point.
What is the primary beam?
X-rays that emerge from the window of the tube head, usually visualised by the light beam diaphragm.
What is the actual focal point of an radiography machine?
The spot where the electrons hit the target, the target is angled at 20 degrees
What is the effective focal spot of the radiography machine?
Because the target is angled the x-ray beam that leaves the target is narrower and more defined.
What is the tube head?
Encases the anode, cathode and the light beam diaphragm
What is the tube head lined with?
Lead.
Why is the tube head lined with lead?
To absorb the X-rays that are produced in different directions to the primary beam
What is the line voltage compensator.
Will stop fluctuations in normal mains electricity
What is a stationary anode?
Limited mA can be used with this anode as it will only withstand a certain amount of heat.
What is a rotating anode?
And set into a rotary arm, constantly turning, and therefore withstand more heat
What is the KV?
The speed and energy that the electrons hit the target, also known as the potential difference.
What is the mA?
The quantity of electrons hitting the target.
What are calcium tungsten screens?
These will only emit blue light. The image is less defined.
What light does rare earth phosphorus screens?
These emit green light
What is the pro of using Rare Earth Phosphourus Screens?
Absorb more x-ray energy and are efficient at converting this energy into light.
Better defined image
Lower exposure can be used
How many layers are the sheets of an x-ray film mad up of?
Several
What is the top layer of the x-ray film called?
Known as the emulsion.
Where are silver bromide crystals found?
In the emulsion layer of the x-ray film.
What are silver bromide crystals sensitive to?
Sensitive to x-rays and white light.
What is the second layer of the x- any film?
Known as the subbing layer
What does the subbing layer of the x-ray film do?
Sticks the emulsion to the third layer (the base)
What is the super coat of the x-ray film?
A protective gelatine coating
What is a non-screen?
For use without an intensifying screen, the image is produced by x-ray energy only. High mA is require
What is monochromatic screen film?
Sensitive to blue light only
What should a monochromatic screen film be used with?
Only to be used with calcium tungstate screens as these emit a blue light only
What is the orthochromatic screen film?
Can be used with either type of screen as they are sensitive to blue and green light
What is duplitised?
- Emulsion on both sides = double efficiency
- Good contrast and blackness but reduced definition due to marginally superimposed images
What 3 things do we need to know about single-sided film?
- Emulsion is one side only
- Very fine detail image with good soft tissue and bone detail
- Need to increase exposure factors
What will a fast film and screen allow?
Lower exposures but the definition of the image will be less.
What does a slow film and screen combination require?
Higher exposure.
What are the white light filters?
Red filter and brown filter
What films do you use with a red filter in radiographs?
Use with blue/green light sensitive films
What films do you use with the brown light filter?
Use with blue light sensitive films
What is in the developer of an x-ray machine?
Alkaline Phenidone hydroquinone or metal hydroquinone
What does the fixer do?
🔶 fixer will dissolve any unexposed silver bromide known as clearing time.
🔶 preservative
🔶 hardener to prevent further softening, known as tanning
What is the developer also known as?
Known as reducing
What does this developer do?
Converts exposed crystals to of silver bromide into metallic silver
What does the developer contain?
Contains buffers to maintain alkalinity
What do the strainers in the developer do?
Limit use of reducing to exposed silver bromide only
Where are hardeners found?
Found only in automatic developing solution, will prevent excess swelling and softening of emulsion
How will you be able to tell that the developer is exhausted?
Will show as an under developed film