TCDHA Rad Theory-Weeks 10-15
Film Processing - Answer- a series of steps that produce a visible permanent diagnostic image on a dental radiograph
purpose of chemical processing - Answer- 1) covert latent image-> visible image
2) preserve visible image
latent image - Answer- invisible i...
TCDHA Rad Theory-Weeks 10-15
Film Processing - Answer- a series of steps that produce a visible permanent
diagnostic image on a dental radiograph
purpose of chemical processing - Answer- 1) covert latent image-> visible image
2) preserve visible image
latent image - Answer- invisible image
- becomes visible under special dark room conditions
-remains invisible within the film emulsion until it undergoes chemical processing
procedures.
silver halide crystals - Answer- -absorb x-radiation during X-ray exposure and store
X-ray from the radiation
reduction - Answer- -the halide portion of the exposed, energized silver halide
crystals are removed
-result in black metallic silver images
selective reduction - Answer- -reduction of energized- crystals = black metallic silver
-unexposed, unenergized crystals= removed from film
developer solution - Answer- -chemical solution
-distinguish between exposed/ unexposed silver halide crystals
-initiates chemical reaction- reduces exposed silver halide crystals -> black metallic
silver + dark/black areas on radiograph
-unexposed crystals= unaffected by developer
- ideal temp= 20C (68F)
fixer solution - Answer- -chemical solution
- removes unexposed halide crystals= white/clear areas on radiograph
- the black- metallic silver remains on the film (not removed)
film processing solutions - Answer- -fresh chemicals produce best radiographs
-replenished daily- changed every 3-4 weeks
developing/reducing agent - Answer- - optimum temp= 68F
-hydroquinone- converts exposed crystals to black metallic silver= producing black
tones and contrast
-elon/metol- converts crystals to black metallic silver= many shades of grey on a
radiograph
preservative (developer) - Answer- sodium sulfite- prevents oxidation of the
developing agents
,accelerator - Answer- sodium carbonate- activates developing agents
-provides alkaline environment for developing agents
-softens gelatine of film emulsion
, developer/fixer cut-off - Answer- cause: -low level of developer/fixer solution- partial
image
-films not being immersed
overlapped film - Answer- 2 films come in contact with each other during processing
air bubbles - Answer- Air is trapped on the film surface after the film is placed in the
processing solution
fingernail artifact - Answer- rough handling of film damaging film emulsion with
operators fingernail
fingerprint artifact - Answer- from touching film with contaminated fingers of
developer or fluoride
scratched film - Answer- film emulsion is removed from base by a film clip/hanger
fogged film - Answer- improper safe lighting and light leaks in dark room, film storage
contaminated processing solutions
high developer temperature
expired films
light leak - Answer- white light exposure
defective film packets
radiolucent - Answer- -black
-large deposits of black metallic silver appears black
-Readily PERMITS the passage of the x-ray beam and allows more x-rays to reach
the film.
Radiopaque - Answer- P = PAPER = WHITE
Resists the passage of the x-ray beam and restricts or limits the amount of x-rays
that reach the film.
manual film process - Answer- Developing
Rinsing
Fixing
Washing
Drying
automatic film processing - Answer- Development
Fixing
Washing
Dryin
view box/illuminator quality assurance - Answer- -shoud emit uniform/subdued light
when functioning properly
-examined for dirt/discolouration
-wiped clean
-discoloured=replace
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