Radiography - know how to process radiographs Flashcards
(40 cards)
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