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57 Cards in this Set

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  • Back
film emulsion consists of silver halide grains that are both ________ and _______
photosensitive and radiosensitive
To creat distortion between the regular arrangement of the silver and bromide ions in the crystalline lattice, what is added
large iodide ions
what is another name for sensitivity sites
Latent image sites
how are the silver halide crystals made more sensitive
addition of trace amounts of sulfur

NOTE sulfur compounds creat the sensitivity sites that contribute to latent image formation
What happens at the latent image site
xrays knock an electron off bromide converting it to bromine. These electrons strick a latent image site and give it a negative charge which allows the site to attract free silver ions to itself
What begins latent image formation
Sensitivity sites

Each Ag Halide crystal has multiple sensitivity sites
During what process does the conversion of silver ions in the crystal to mettalic silver occur
processing

the black metallic silver grains can be visualized after processing
What are the 2 types of processing
Manual and Automatic
Give the steps in both manual and automatic processing
Manual - Wetting, Developing, Rinsing, Fixation, Washing Drying

Automatic - Developing, Fixation, Washing Drying
What is the optimal temp for manual processing
68-70 deg F
What is the primary function of developer
conversion of silver halide into metallic silver atoms
What is the primary reducing agent in the developer
Phenidone - it is an electron donor(thus its oxidized), that converts the Ag ions into black metallic silver atoms at the latent image site
What is the secondary reducing agent in the developer
Hydroquinone - it reduces the oxidized form of Phenidone to its original reduced state so it can be ready for another cycle

Hydroquinon also helps build up contrast thru gray, black and white tones
What is the name of the alkali compound or activator in the developer
Sodium or Potassium hydrozide

they help keep the pH around 10 and softens the gelatin for difussion of the developing agent.

NOTE: Sodium Carbonate Acts as a buffer to maintain alkaline pH
What is the name of the preservative or antioxidant in the developing solution
Sodium sulfite -
it prevents rapid oxidation of developing agent by O2, extends the life of dev agent and removes oxidation products that may interfere and stain the film
What is used as the restrainer in the developing agent
Sodium Bromide(antifog agent) - it restrains the development of unexposed Ag halide crystals thus preventing fog
What is the primary function of the fixing agent
removal of unexposed or underdeveloped Ag halide crystals. Also hardens and shrinks the film emulsion
What is the name of the fixing or clearing agent
Ammonium Thiosulfate -
it removes unexposed Ag halide grains from film emulsion
What is the name of the acidifier in the Fixating solution
Acetic Acid-
maintains pH around 4 to 4.5. It promotes difussion of ammonium thioslufate and removes silver thiosulfate out of the emulsion. Also blocks development of unexposed crystals
What is the name of the preservative in the fixating solution
Sodium or Ammonium Sulfite -
keeps chemical balance, prevents oxidation of thiosulfate clearing agent, binds with any colored oxidized developer carried into the fixer and removes it and prevents oxidized developer from staining the film
Films turn brown after time if you what
you use depleted solution or you didnt wash it properly
What is the hardner compound in the fixation solution
Aluminum Salts - reduces swelling of emulsion during final wash by limiting water absorption and drying times. Also prevenet damage to the gelatin during hardening
What can result in darker radiographs(higher density)
Prolonged development
What can result in a gradual loss of film density
Excessive fixation
What does the washing process do below 60 deg F
the efficiency declines rapidly
What is washing done for
to remove all residual processing chemicals(thiosulfate and Ag thiosulfate complexes) that may obscure the diagnostic info in the final image
What is the reason for discoloration
improper washing

Thiosulfate + Ag = Silver sulfide(brown)
What is the drying proess done for
Removes moisture from the film and prepares it for viewing
What can uneven drying lead to
distortion of gelatin and thus variation in density may be seen
What are some steps you need to take before starting manual processing
- adequate safelight in room
- check solution levels
- stir solution frequently
- check solution temp.
- unwrap exposed film package
- load film on hangars
- set interval timer
- process your little ass off
Give the steps and times for the manual processing procedure
wetting in develop(30 sec)
development (5 min at 68 F)
water rinse(30 sec)
Fixation (10 min)
Washing(10-15 min)
Drying(30 sec)
Why is auto processing better
Shortens time to 1.5 to 6 min
rollers move films
contrast end results
less floor space
daylight loading possible
less required equipment
wet reading of films is eliminated
What are the functions of the rollers
move the film along the process, uniformity, prevents carry over contamination between solutions, and rolling motion stirs solutions for you
What are the characteristics of the developer and fixer
developer is alkaline and feels soapy

fixer is acidic and has a sharp smell
What are some chemicals that are added to the automatic developing solution
Gluteraldehyde(hardener, might be active ingredient in Viagra)

Sulfate(minimize swelling)
What are some of the time/temp correlation of the time required to process automatically
90 sec at 90-95 deg F
4.5 min at 83 deg F
What are some precautions to take when feeding films
slowly and carefully,

dont feed
wet/damp films, too rapidly or bent films
What does uneven drying cause
distortion of the gelatin and spots on the film

Dry in no higher than 49 deg C and make sure its adequately ventilated
Why should you change film processing solutions every day even if you dont use them
The air oxidizes the compounds - developer does this
What can the use of exhausted developer result in
slower development times and reduced density and contrast

Density - amount of blackness on film
Contrast - differences in densities
What can use of exhausted fixer cause
slower removal of unexposed crystalls and silver thiosulfate complexes which results in incomplete clearing and films turn brown with age
What is a step wedge used for
the check image quality when solutions are changed(its a reference film)
when do you know its time to change solutions
when you notice loss of density and contrast(you wont be able to see outlines of your step-wedge)

NOTE change both solutions at the same time
What are rapid processing chemicals and what are they used for
they are more concentrated and work in about 15 sec develop and 15 sec fixation. Typically used for emergency or endo situations.

HOWEVER they are not recommended cause they can become discolored over time and provide lower film contrast
how can you improve the rapid processing chemical films
regular fixation for 4 min and washing for 10 after view will improve contrast and storage
What are some things that should be done to the automatic processor maintenance wise
inspect rollers for allignment
lube moving parts monthly
solution replenishment every
15-30 days (KEEP A LOG)
open cover at end of day to let air out
what things should you look for in a safelight in your processing room
Color of filter, distance and wattage, and safelight exposure time
What are the recommended safe lights
Kodak ML-2(yellow/orange color) - its used with intraoral D(ultraspeed) film only cause it can fog extraoral and F speed film

Kodak GBX(ruby red color) - safe with all extraoral and intraoral films thus its called the universal filter
What are the recommended distances and wattage for your safelight
15 watts and min 4 feet
how do you test the safelight in your darkroom
unwrap film and place a penny on it, leave the film on the workbench for you amount of time it takes to open a packet and feed it into processor. Then process the film, if penny is visible then your safelight sucks ass get a new one!!!!!
What are the 2 primary ingredients of radiographic waste management
disolved silver in used fixer which is disposed by electroplating

lead foil in film packets which should be sold to scrap metal dealer

MAKE SURE THE COMPANIES ARE LICENSED TO DO THESE PROCESSES
what is the process to mount and view the film
raised dot towards the viewer, dot is always toward the occlusal surface, use magnifying glass and block all extraneuous light
Give some examples of where the dot should be
in PA film it is always towards the occlusal surface of the teeth

BUT
in occlussal the dot is towards the lower edge in BITEWING FILMS at OUCOD
What are the reasons for mounting dental radiographs
less chance of error in interpretation, prevention of finger marks, scratches and abrasions. Easy to file and review. Educational value to the patient
Film duplication procedure
Direct reversal film- solarized by light or checmical treatment of emulsion

More light exposure produces less density

The side of the film with emulsion is purple --- only 1 side has emulsion on this type of film
What is on the side opposite the emulsion side on a Film Duplication procedure
antihalation coating - it absorbs the reflected light before it reaches the emulsion again

IT REDUCES UNSHARPNESS
Where is the film duplication procedure done
in the darkroom, using an ultraviolet light source.
the original radiograph and duplicating film placed in close contact with emulsion side
Greater the exposure time lighter the film

KODAK X-Omat duplicating film