Quality Assurance & Fault Analysis

Question 1

What is the purpose of quality assurance in dental radiology?

Answer 1

To ensure
- consistently adequate diagnostic information
- radiation doses are monitored

Question 2

How does quality assurance apply to digital image receptors in dental radiology?

Answer 2

Reusable digital receptors suffer wear & tear which will eventually impact image quality & necessitate replacement

Question 3

How often should digital radiograph receptors be formally checked?

Answer 3

every 3 months (or sooner)

Question 4

What 3 things should be checked when assessing the standard of a digital radiograph receptor?

Answer 4

1. the receptor itself
2. image uniformity
3. image quality

Question 5

What checks should be done specifically on the digital image receptor itself?

Answer 5

• check for visible damage to casing/wiring
• check if clean

Question 6

How can image uniformity of a digital receptor be checked?

Answer 6

expose receptor to an unattenuated X-ray beam & check if resulting image is uniform

Question 7

How can image quality of a digital receptor be checked?

Answer 7

Take a radiograph of a test object & assess the resulting image against a baseline

Question 8

What may damage to the phosphor plates present as on the radiographic image once taken?

Answer 8

1. scratches = white lines
2. cracking = network of white lines
3. delaminating = white areas around edge

Question 9

What may damage to the solid-state sensors present as on the radiographic image once taken?

Answer 9

white squares/straight lines

Question 10

What can be used to check image quality of radiographs?

Answer 10

A step wedge

Question 11

QA of clinical image quality aims to ensure that radiographs are consistently adequate for diagnostic purposes, what does this consist of?

Answer 11

1. image quality rating
2. image quality analysis
3. reject analysis

Question 12

What should bitewing radiographs aim to show?

Answer 12

• show entire crowns of upper & lower teeth
• Include distal aspect of the canine & mesial aspect of the last standing tooth
• every approximal surface shown at least once without overlap

Question 13

What is fault analysis?

Answer 13

Identifying & explaining faults so that they can be remedied

Question 14

What are some potential faults that could be visible on the image?

Answer 14

• too dark or pale
• inadequate contrast
• not sharp
• distorted
• over-collimated
• receptor marks/damage

Question 15

How can collimation errors occur?

Answer 15

• incorrect assembly of receptor holder
• incorrect alignment between X-ray tube & receptor holder
• incorrect orientation of the rectangular collimator

Question 16

How can incorrect image radiodensity occur?

Answer 16

• incorrect exposure settings, patients tissues too thick
• developing factors in film
• inappropriate light source for viewing