QA and QC

QUALITY CONTROL AND QUALITY ASSURANCE OF DENTAL RADIOGRAPH

  1.     DENTAL SYSTEM CONSTANCY TEST

     -To assure the processing and dental intraoral x-ray unit are operating consistently.

  2.     PROCESOR QC (SENSITOMETRY)

-     To determine if film processor is working optimally in facilities producing radiographs other than intraoral.

-     It should be:

± 0.15 optical density of the mid-density step

± 0.15 optical density of the density difference

+ 0.03 optical density of the base + fog level

-Steps:

1. Expose the control film with the sensitometer and develop

2. Determine the average optical density of the mid-density step and record on Form

    B1 in Appendix B.

3. Determine the average optical density difference and record.

4. Measure the background optical density (base + fog) and record.

5. Verify that the measured values are within the suggested performance criteria.

  3.      DAILY AND WEEKLY DARKROOM QC

       -Keep the darkroom clean and processing optimized.

       -Steps: 

         Daily:If manual processing, developer temperature must be measured with non-mercury

thermometer for correlation with the time-temperature chart.

If auto processing, measure the temperature with a non-mercury thermometer to

verify that the developer is operating within the temperature range established by the

manufacturer, and that the display, if applicable, is accurate. It may not be necessary

                  to physically measure the temperature daily if the processor passes the daily QC test (1).

    Daily: If manual processing, replenish following the chemistry manufacturer guidelines.

  Replace rinse water.

  If auto processing, follow the processor manufacturer recommendations regarding

  replenishment.    

    Daily: Clean processor feed tray and counter top.

    Weekly: Damp mop darkroom floor. Clean counters, cabinets, and anywhere else dust may

      accumulate. Clean film hangers.

  

  4.     VIEWBOXES

       -To ensure viewboxes are clean and light levels are kept consistent.

       - Suggested Criteria:

        Viewbox lights are the same “color” and luminance, and viewbox surfaces are kept clean.  - Steps:

1. Clean surface of viewbox.

2. If a bulb or tube fails, it is best to replace all of them.

3. Record results on the Monthly QC Checklist (Form 3)

  5.      VISUAL CHECKLIST

       -To assure that all components of the radiographic x-ray system (indicator lights, displays,

         and mechanical locks and detents) are working properly and that the mechanical rigidity 

         and stability of the equipment is optimum.

       -Suggested Criteria:

        Each of the items listed in the QC Visual Checklist (Form 2)should pass or receive a check mark. 

        Items not passing the visual check should be replaced or corrected as soon as possible.

  6.     REPEAT ANALYSIS

       -To identify ways to minimize patient exposure and reduce costs by addressing higher

         than normal repeat rates.

       - Suggested criteria: 

          The criteria associated with repeating a film is subjective. There is no good way to

          determine what the repeat rate should be. Each facility should decide on its own, but

          should strive for a repeat rate of no greater than 5 to 7 %.

  7.     DENTAL TUBE HEAD AND BOOM STABILITY TEST

      -To assure the intraoral x-ray tube remains in the correct location.

      -Suggested Criteria : Tube does not drift out of position or oscillate.

      -Steps:

1. Position the tube as you would with a patient in the chair.

2. Watch for any movement after you have positioned it.

3. Check all typical tube positions.

4. Record your results on the Quarterly QC Checklist (Form 3).

  8.     FILM AND CHEMICAL STORAGE

      -To assure film and chemistry quality are maintained and inventory is rotated on a first in,first out basis.

  9.     INTENSIFYING SCREEN CLEANING

       -To assure that screens and cassettes are free of dust

       -Suggested Criteria: 

           Minimize artifacts on films from screens or cassettes.

  10. PANORAMIC SLIT ALIGNMENT TEST

      -To assure that the radiation field is in proper alignment with the slit on the panoramic unit 

          image receptor.

       -Suggested Criteria:

          Opening on the x-ray tube is in alignment with the opening in the image receptor.

        -Steps:

1. Tape film packets to the top and bottom of the slit on the image receptor. See

Figure 1 for set-up.

2. Mark the position of the slit on the film packets with a ballpoint pen. (Press hard).

3. Expose the film.

4. Develop the film.

5. Observe if the exposed portion of the film is in alignment with the demarcation

caused by the use of the pen in Step 2.

6. Record results on the Annual QC Checklist (Form 4)

EXAMPLE OF CHECKLIST( FORMS)