Topic 7: the importance of reject analysis in the digital age

Question 1

what is a reject analysis

Answer 1

a QA test that identifies why images have been rejected and how the number of rejected images can be reduced

Question 2

what is reject analysis both apart of

Answer 2

QA and QC control operation

Question 3

QA quality assurance

Answer 3

equipment is tested to improve or standardise
- are we operating the devices properly

Question 4

QC quality assurance

Answer 4

equipment is tested to identify defects
- ‘Are the devices, themselves, operating properly’

Question 5

some implications of rejecting an x ray in digital age

Answer 5

• the process has become faster and simpler
• digital imaging has introduced new LUTs and types of image receptors which has reduced the dose of plain film
• rejecting image no longer requires separate film

Question 6

what are the stochastic effects of rejecting an x ray

Answer 6

• random and have chance to occur after any dose
• higher dose of radiation given means higher chance of stochastic effect
• stochastic effects are generally carcinogenesis/ genetic mutation

Question 7

what do deterministic effects describe

Answer 7

describe a cause-and-effect relationship between radiation and certain side effects

Question 8

when do we reject an image

Answer 8

• if images produced do not provide a means to answer the clinical question
• if your images are sub-optimal and an accurate diagnosis cannot be made
• if images deviate from standard examination protocol/ no accurate justification

Question 9

how does reject analysis benefit the imaging department

Answer 9

• protocols can be optimised to ensure best image is taken
• any areas where staff knowledge or technique lacks = training organised
• patient radiation dose can be more easily tracked
• image quality can be assessed

Question 10

what would the department do in the case of under-exposure?

Answer 10

• review protocols
• staff technique re training
• QA testing

Question 11

what would the department do in the case of over exposure

Answer 11

• review protocols
• staff technique re training
• QA testing

Question 12

what would the department do in the case of patient positioning

Answer 12

• staff technique re training
• new equipment/ replacement equipment

Question 13

what would the department do in the case of an artefact

Answer 13

• staff technique re training
• QA testing
• engineer review

Question 14

what would the department do in the case of equipment failure

Answer 14

• QA testing
• engineer review

Question 15

what do LUTs tell you

Answer 15

• tell the processing unit what value to give a pixel of a certain value
• curve produced as a result of applying LUT
• shape data to resemble a characteristic curve

Question 16

in the digital age, what is the most common reason for image rejection

Answer 16

patient positioning