Radiography - know how to process radiographs Flashcards
what temperature should the processor be before it is used?
28 c
define latent image
invisible product of x-ray or photographic film emulsions
how many stages are there in manual processing?
5 development rinising fixing washing drying
How many stages are there in automatic processing?
4
no risnising
What is the active ingredient in the development?
either Phenidone hyrdoquinone or metol hydroquinone.
What happens if the images in left in the development too long?
it will start to blacken
How long should the film be in the developer for?
3-5 minutes
Which stage will stop further development of the film?
Fixing
Is the fixing solutions Acidic or Alkaline?
Acidic
What can happen if the developer is transferred to the fixer with out washing it first?
it can produce a dichroic fog on the film
What is the active ingredient in the fixer?
Sodium or ammonium thiosulphate
Define ‘Clearing time’ ?
length of time the fixer take
What temperature should the fixer not go above and why?
21 - might cause staining
How long should the washing process take place in manual processing?
at least 10 minutes, ideally 15-30 minutes
In manual processing explain the drying process?
remove films from their hangers and clip onto a line and above a sink in duct free area and allow to drip dry. film must not be clipped to close together
What are factors of good quality radio-graphs?
Film density - degree of blackening
film contrast - difference in density between different structures
resolution - the ability to distinguish Small changes in shape and size
sharpness - the clarity which the structures can be seen.
What might cause a film to be too pale? and how would you remedy it?
underexposed - check size of patient, increase settings, check film screen combinations.
underdevelopment - check developer temp and time.
FFD to long
What might cause a film to be too dark? and how would you remedy it?
Overexposure - reduce settings, the size of patient, check film/screen combinations
over development - check developer temp and time
fogging
FFD to short
what might cause patchy film density? and how would you remedy it?
developer no stirred
film not agitated in developer
need to correct the developer technique
What is meant by soot and white wash? and what might cause it?
Contrast too high. KV to low - need to increase
what might cause fogging?
scatter radiation - collimate beam and use grid
exposure to light before fixing - check dark room and safety light, make sure lids on boxes.
chemical or developer fog - avoid overdevelopment
What is meant by flat film? what might cause it and how would you remedy it?
contrast to low
Overexposure - reduce exposure
underdevelopment - correct development technique
overdevelopment - correct development technique
fogging - collimate, don’t expose film to light, advoid over development
What might cause a image blurring?
patient movement tube head movement scatter fogging poor film screen contact large object - film distance double exposure.
what might cause small bright marks on a film?
dirt on intensifying screens
what might cause black patches on a film?
developer splashes on film
what might cause white patches on a film?
fixer splashes on film
what might cause grey patches on a film?
water splashes on film or chemical slashes on intensifying screen
What might cause scratches on a film?
Careless handling of film or guides-shoes on automatic processor.
what might cause crescent shape marks on film?
bending for unprocessed film
what might cause branching marks on film?
static electricity
what might cause parallel marks on film?
roller marks
what might cause scum on the surface of the film?
scale or algae in the processor
what might cause yellow/browning on storage ?
insufficient fixing or washing
What might cause areas on the film that are meant to be clear to turn grey and opaque?
insufficient fixing
what might cause borders around the film?
dirty channel hangers
what might cause the grid lines too coarse?
x-ray beam not perpendicular to grid
focused or pseudo grids upside down
why might the automatic processor produce damp films?
thermostat malfunction
dryer temperature too low
insufficient fixing
what are the two types of digital radiography?
Computed radiography and direct digital radiography.
Explain how computed radiography works?
The imaging plate (IP) absorbs the x-rays and stores them as energy.
The IP is inserted into a digitzer and the IP is stimulated to release the image by laser beam.
The image then appears on a work station (computer)
what are the two types of direct digital radiography ?
Flat panel system - flat panel converts the x-rays energy to light and then to a digital signal to be interpreted by computer to produce an image file.
charged couple device system - rely’s on a fluorescent screen positioned directly under the x-ray tables and the screen in linked to a charged couples device.
