Radiography Flashcards
What bulb wattage would you use in a safe light?
15w
The active ingredient in developer is
Phenidone - hydroquinone
Optimum temperature for a manual processing developer is
20oc
The active ingredient in fixer is
Ammonium thiosulphate
How long should a radiograph be washed for prior to drying
15-30 min
What stage is omitted from an automatic processor
Rinse/stop bath
At what temperature should automatic processing chemicals be kept?
28oc
The quantity of xrays produced depends on
Miliamperage and length of the exposure
Blurring of one part of the film will occur due to
Poor screen film contact
Out of metal, bone, fat and soft tissue which is the most radiolucent?
Fat
Which combination will give you the best definition?
Slow film, slow screen
Which one affects the quality of the xray beam?
The kilovoltage
White patches on a film may be caused by
Fixer splashes onto film before processing
Which one has a higher atomic number than bone?
Metal
Blackening of the film is caused by
Kilovoltage and miliamperage
The max dose of radiation a member of general public over 18 may receive in a year is
5msv
What could you use to reduce radiation hazards by the greatest amount?
Use of rare earth screens
Which affects radiographic contrast?
Kv
What will help to improve definition of x Ray image?
Use of a non screen film
An xray film is too dark that you have processed. How would you correct this error?
Reduce exposure time
A processed film is very grey with poor contrast between image and background
What could be the cause?
Film fogged by radiation
A rad of an aesthesthetised animal is blurred what might be the cause?
Poor film/screen contact
What mark or artefact would insufficient washing after fixation leave on a finished radiograph?
Yellow stains
What are the two major components of an x Ray film emulsion?
Gelatin and silver halides
What are advantages of rare earth screens?
Decreased patient dose
Improved image quality
Reduced tube current
What film fault is responsible for white spots on radiograph?
Dirt on intensifyinh screen
Chemicals that are a constituent of the fixer?
Ammonium thiosulphate
Boric acid
Sodium acetate
Which is the fixing agent used in a fixer?
Ammonium thiosulphate
Which is removed from the film during fixing?
Silver halide
Where would you find an intensifying screen?
In an x Ray casette
You have developed a radiograph using the wet tank methid and film has turned out yellow. What is this due to?
Fixing time is too short
When taking a ventro dorsal rad if the cervical spine, the disc spaces will be viewed most accurately if
The neck is supported with sand bags
When positioning a dog for a bva/kennel club hip radiograph, the beam should be centred on
The public symphysis
Use of rare earth screens may decrease exposure factors by
90%
The speed of the intensifying screen is increased by
A thick fluorescent layer of large crystals
What effect will faster speed have on the definition of film image
Decreased
What is the exposure fault of a rad with a pale image, of high contrast on a dark background?
Kv too low
The use of a grid requires an increase in the
Mas
The latent image of the exposed radiation is the result of
Exposure to light/x Ray photons
If you were developing non screen film manually, how much longer would you leave the film in developer compared to screen film?
Double the normal developing time
What crystal may be found in the rare earth screens?
Gadolinium oxysulphide
What exposure function affects the amount of x rays produced?
Ma
The reflective layer of intensifying screen is to
Reflect light photons back towards the film
The latent image of the exposed radiation is of
Exposure to light/x Ray photons
When developing a non screen film manually how much longer would you leave film in developer compared to screen film?
Double the normal developing time
What crystal may be found in the rare earth screens?
Gadolinium oxysulphide
What function affects the amount of x rays produced?
MA
The reflective layer of the intensifying is
To reflect light photons back towards the film
The visible differences between the varying shades of film image is called the
Contrast
The cloud of electrons Is produced at
The cathode
How much electron energy is lost via heat production?
99%
What is the filter made of that x Rays have to pass through when leaving the tube head?
Aluminium
The anode is
Negatively charged
The target (anode) is set at which angle?
20oc
What does kv control?
Penetrating power
Which grid type will not result in presence of visible parallel lines on a radiograph?
Potter bucky
The exposure for a lateral chest xray has 60kv 16mA at ffd of 75cm. What is correct mA if ffd is changed to 60cm
10mA
Too high kv produces a film
Low in contrast
Gas will show on a rad as
Nearly black
Soft tissue on a rad will show as
Mid grey
Underdeveloped film will produce an x Ray that’s
Too pale
Stationary anode produces
Limited x ray production
The envelope that contains anode and cathode is made from
Pyrex
The focusing Cup in x Ray tube head is commonly made from which one of the following metals
Nickel
The anode is made from what metal?
Tungsten
The anode of the xray tube head attracts
Electrons
1% energy used in tube head creates x Rays, the other 99% of energy is converted into
Heat
In a stationary anode the target is embedded in a stem of
Copper
The usable x ray beam comes from an area of the anode called the
Effective focal spot
What does the kv NOT control?
Quantity of electrons produced at cathode
It does control the speed at which electrons travel, the penetration power of xray beam and the energy of the electrons
What is the light sensitive part of x Ray film emulsion?
Silver halide crystals
What film type is sensitive to green light?
Ortho chromatic film
Which study would you use non screen film for?
Dorsal ventral view of the internal nares
The phosphor calcium tungstate emits which colour of light when it fluoresces?
Blue
What are advantages of using intensifying screen?
Reduces exposure time
Reduced movement blur
Decreased tube voltage
Fast screen film combinations:
Have large silver halide crystals and large screen phosphor crystals
Slow screen film combinations -
Have small silver halide crystals and small screen phosphor crystals
Intensifying screens
Reduce exposure time
Reduce overall definition of finished radiograph
They’re very fragile and easily damaged
They are Not used singly
Screen film contact can be checked by
Placing chicken wire over the x Ray casette, exposing film briefly to primary beam and then processing film
If a proprietary brand of screen /casette cleaner is not available what produce would be best?
Options are hibiscrub, water, pevidine or saline
Water
After cleaning casette what is best way to leave it to dry
Open standing upright, like a book
Functions of x Ray casette
To hold intensifying screens and protect them from damage,
To exclude all light from casette
To maintain a close and uniform contact between screens and films
What is x Ray film not sensitive to?
Options are gamma rays, radio waves, uv light or pressure
Radio waves
A fast film requires
Short exposure time
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Is a parallel grid
Grids are useful at absorbing
Scattered radiation
What is a moving grid
A Potter bucky diaphragm
Which of the following is least expensive type of grid
A parallel grid
Crossed
Focused
Pseudo focused
A parallel
The usual time an x Ray film needs to be processed for is
3-5 mins
Developer is
Alkaline
A common chemical used as the stopping agent is
Acetic acid
Fixing a film is done for which reason
Dissolve and removed the unexposed silver halides from x Ray film
The emulsion of non screen film is thicker than that of screen film. What changes would you make to the processing time
Increase the devolment time and increase fixing time
The accelerator potassium carbonate is often included in developer to
Increase alkalinity of developer
Preservatives are included in developer to
Slow down the time it takes for developer to oxidise
Restrainers are used in the developer to
Decrease amount of developmental fog
A common preservative in fixer is
Sodium sulphite
A radiograph can be viewed briefly in dark room after approximately how long in the fixer?
1minute
Buffers are included in the fixer to
Maintain PH of fixer
How long should a processed radiograph be washed for in circulating water
20-30 min
Wat are methods of silver recovery
Metallic replacement
Electrolytic recovery
Chemical precipitation
Lateral rads should be viewed so that
The spine runs parallel to the top of the light box and head points towards viewers left hand side
The subbing layer of a piece of x Ray film could also be called
Adhesive layer
What’s the minimum lead equivalent of an apron
025mm LE
What substance is commonly used in protective clothing
Lead
What imaging technique produces cross-sectional views of a patients body?
Computed tomography
What technique involves patient having a radioactive isotope introduced to the body?
Radionuclide imaging
What study would you use contrast medium barium sulphate for?
Gastrophagy
What is a non-ionic water soluble iodine contrast medium?
Iopamidol
Xrays and gamma rays are
High in frequency, short in wavelength
Xrays are produced by
X Ray machines
Xrays are produced when fast moving
Electrons hut a target at high speed
The ‘high potential difference’ is measured in
Kilovolts
What is the filter made of through which all x rays have to pass, prior to leaving tube head?
Aluminium
What metals line the tube head?
Lead
Which of the following gases is not used in contrast studies
Carbon dioxide
Room air
Oxygen
Carbon monoxide
Carbon monoxide
What contrast media should be used for myelogram?
Iopamidol
What part of the xray machine limits primary beam size and lessens secondary radiation. Exposure to personel?
Light beam diaphragm
What may give an Increased chance of being exposed to ionising radiation?
Repeated exposures
What would decrease the likelihood of radiogrpahs turning yellow over a period of time?
Allowing more time for radiograph to be fixed
Which safelight filter is commonly used when handling ortho chromatic film?
Dark red
Which safe light filter is commonly used when handling monochromatic film?
Brown
Which is the correct sequence when processing a film manually
Develop, stop, fix, wash, dry
What is the correct sequence when using an automatic processor
Develop, fix, wash, dry
What term best describes the distance from the tube head to the film casette?
Film focal distance
Dichroic fog is caused by
Insufficient washing
Patchy film density may be caused by
Film is not agitated in developer
