rad ch 17

Screen-film contact test

Cassette holders must be examined every month for worn closures, light leaks, and warping. Screens should be cleaned monthly with commercially available cleaners

Clearing test

Monitors fixer strength-how quickly it "clears" or removes unexposed silver halide crystals

Quality Assurance

Special procedures that are used to ensure the production of high-quality diagnostic images Includes quality control tests, and quality administration procedures

Quality administration

management of the quality assurance plan in dental office. the dentist is ultimately responsible for overall quality assurance. The basic elements of a quality administration program include, -description of the plan -assignment of duties -monitoring schedule -maintenance schedule -record-keeping log -plan for evaluation and revision -in-service training

screens and cassettes inspections...

monthly

processing equipment must by checked daily. thermometer and timer must be accurate, temp and level of water bath, developer and fixer solutions must be

checked. the "automatic processor test" can be used to check the functioning of the automatic processor. these tests and checks must be performed daily

To check strength of developer strength:

compare film densities to a standard

computer backup of the digital data should be done how often?

daily

processing solutions: the developer strength can be monitored by a reference radiograph, stepwedge radiographs, or a normalizing device. the fixer solution can be checked by performing a clearing test. these tests must be performed

daily

the densities seen on the daily image appear lighter than the densities seen on the reference radiograph; this result indicates?

developer solution is too weak developer solution is too concentrated developer solution is too cold a and c or and b

operator error that requires retakes must all be recorded quality control tests are used to monitor dental x ray equipment, supplies, film processing and

digital imaging

calibration of dental x ray equipment can be performed by a dentist, dental hygienist, or dental assistant

f

Fast clearing

film clears in 2 minutes, fixer is of adequate strength

Fogged film

film that has expired, been improperly stored, or exposed to radiation appears fogged

The clearing test is used to monitor

fixer strength

digital imaging must be checked for quality assurance too. a side by side comparison can be made. this test will reveal discrepancies with image sharpness, density and contrast. images may become _______ overtime and require inspection by a technician recommended by the manufacturer

grainy

Slow clearing

if film does not completely clear after 2 minutes, re immerse it in the fixer solution

Viewbox (or illuminator)

is a light source that is used to view processed filmsContains fluorescent lightbulbs that emit light through an opaque plastic or Plexiglas front wipe down every week

Most critical component of film processing quality control:

is monitoring of the processing solutions

Step-wedge radiograph

layered aluminum steps. When step-wedge is placed on top of a film and then exposed to x rays, the different steps absorb varying amounts of x rays Demonstrates optimal film contrast and density

the viewbox should emit a uniformed and subdued

light

annual tests must be performed on x-ray machines designed to identify minor malfunctions like

machine output variations, inadequate collimation, tubehead drift, timing errors, inaccurate kilovoltage and milliamperage readings

the screen film contact test can be used to determine the adequacy of contact. this test should be performed ....

monthly. more frequent testing should be made if the screens and cassettes are used frequently

Light leak test: no light leaks

no visible light is seen

film processing, is one of the most critical areas in quality control and requires daily monitoring. processing problems have the potential to result in a large number of

nondiagnostic images

Fresh film

processed film appears clear with a slight blue tint, the film is fresh and has been properly stored and protected.

Reference radiograph

processed under ideal conditions and then used to compare the film densities of radiographs that are processed daily. Using a step-wedge and correct exposure factors, expose and process one film demonstrates optimal film contrast and density

the dentist is ultimately responsible for the diagnostic quality of all dental images exposed regardless of who exposes them. therfore the dentist relies on the competence of the dental radiographer for exposure, ...

processing and image retrieving

The coin test is used to check

safelight

Quality control tests

specific tests used to maintain and monitor dental x ray units, supplies, film processing, and digital imaging equipment

a detailed written description of the quality assurance plan used in the dental office should be on file and made available to all participating

staff members

a reference radiograph is used to check

strength of the developer solution

Annual test for dental x ray machines can be performed by a dentist, dental hygienist, of dental assistant

t

fresh film and fresh chemicals must be used when preparing reference radiographes

t

fresh film and fresh chemicals must be used when preparing reference radiographs

t

cassettes should be examined for adequate closure, light leaks and

warping

clean viewbox...

weekly

screen film contact test: Inadequate contact

wire mesh image on film exhibits varying densities, poor screen-film contact has taken place

all quality control tests must be done

yearly

view box, digital imaging equipment inspections...

yearly

quality assurance administration procedures include:

1. a description of the quality assurance plan 2. the assignment of duties 3. monitoring schedule 4. maintenance schedule 5. record keeping logs 6. a plan for evaluation and revision 7. in service training

darkroom light leak test should be performed every ....

6 months

screen film contact test: Adequate contact

If the "wire mesh" image seen on film exhibits a uniform density, good screen-film contact has taken place

Step-wedge radiographs

Matched densities. Use the middle density seen on the standard step-wedge radiograph for comparison. density seen on the standard radiograph matches the density seen on the daily radiograph. Unmatched: differs standard radiograph by more than 2 steps on step-wedge

When can safe-lighting be checked?

Only AFTER the light-tightness has been established

Safelighting Test (Coin Test)

Proper safelighting: no visible image is seen on the processed film. Allow 3 to 4 minutes and be at least 4ft from safe-lightimproper safelighting: if image of coin and fogged background appears, the safe-light is not safe to use.

Developer strength tests

Reference radiography, step-wedge radiographs, normalizing device

Darkroom lighting

check for light-tightness every month, and proper safe-lighting every 6 months

The densities seen on the daily image appear lighter that the densities seen on the reference radio-graph; this result indicates:

The developer solution is too weak, and is too cold

Developer stength

When developer solutions losses strength, the time-temperature recommendations of manufacturer can no longer be used as the standard of measurement.

Automatic processor test

Unwrap 2 unexposed films; expose one to light. Functioning processor:* unexposed film appears clear and dry*exposed film appears black and dry

the fresh film test can be used to determine whether film is fresh and has been properly stored and protected. the test should be performed each time....

a new box of film is opened