Quality Assurance

Question 1

Purpose of Quality Assurance

Answer 1

To ensure radiographs are consistently diagnostic information, whilst radiation doses to patients + others are kept ALARP

Taking into account the relevant requirement of IRMER17 + IRR17

Question 2

Why is checking the QA of digital image receptors important?

Answer 2

Wear and tear + mishandling will eventually impact image quality + necessitate replacement

Question 3

What checks to make when checking digital image receptors (3)

Answer 3

1. The receptor itself
   - Visible damage to casing/wiring
   - Check if clean (no congealed disinfectant/saliva)
2. Image Uniformity
   - Expouse receptor to an unattenuated Xray beam + check if the resulting image is uniform
   - Shows a consistent shade of grey across the whole image
3. Image quality
   - Take a radiograph of a test object + assess the resulting image against a baseline

Question 4

How regularly should digital image receptors be checked?

Answer 4

Every 3 months (or sooner if an issue is suspected)

Question 5

How does phosphor plate damage present? (3)

Answer 5

Scratches= white lines

Cracking = network of white lines

Delamination = white areas around the edge

Question 6

How does cracking occur

Answer 6

Overtime if a receptor is mishandles or bent in the patients mouth you start to get cracking

Question 7

How does solid state sensor damage present

Answer 7

White squares/straight lines

Question 8

How does film damage present?

Answer 8

Black marks due to sensitisation of radiographic emulsion

White if emulsion is scraped off

Question 9

Function of Step wedge

Answer 9

Used to check image quality/contrast

Question 10

3 components to Clinical image quality

Answer 10

1. Image quality rating
   - Grading each image
2. Image quality analysis
   - Reviewing images to calculate success rate + identify any trends for suboptimal images
3. Reject analysis
   - Recording + analysing each unacceptable image

Question 11

What should bitewing radiographs show? (3)

Answer 11

1. Entire crowns of the teeth
2. Distal aspect of the fore-standing posterior + mesial aspect of the last standing tooth
3. Every approximate surface shown at least once without overlap
   - May be impossible if crowding

Question 12

What should a periapical radiograph show? (3)

Answer 12

1. Entire root
   - From occlusal surface all the way to apex
2. Periapical bone
3. Crown

Question 13

What is fault analysis?

Answer 13

Identifying and explaining faults so that they can be remedied

Question 14

List some potential faults visible on the image (6)

Answer 14

1. Too dark or pale
2. Inadequate contrast
3. Unsharp
4. Distorted
5. Over-collimated
6. Receptor marks/damage

Question 15

Potential collimation errors (cone cutting) (3)

Answer 15

1. Incorrect assembly of receptor holder
2. Incorrect orientation of the rectangular collimator
3. Incorrect alignment between Xray tube + receptor holder

Question 16

List some potential causes for incorrect image radiodensity (3)

Answer 16

1. Exposure factors
   - Incorrect exposure settings
   - Patients tissues too thick
2. Developing factors (film)
   - Incorrect duration
   - Incorrect temperature
   - Incorrect concentration
3. Viewing factors
   - Inappropriate light source
   inappropriate display screen
   - Excessive environmental light

Question 17

If images are turning out too light or too dark where does the issue lie?

Answer 17

Exposure

- Choosing the correct exposure