Quality Assurance and Fault Analysis Flashcards
What aspects should quality assurance cover?
- procedures (e.g. risk assessment, local rules, contingency plans etc.)
- staff training
- x ray equipment
- patient dose
- image processing
- display equipment
- image quality
Who should a quality assurance programme be created with input from?
a medical physics expert
When should a digital image receptor be checked for quality assurance?
on a regular basis
for example every 3 months (or sooner if an issue is suspected)
What things should be checked when assesing a digital image receptor?
- the receptor itself
- image uniformity
- image quality
How is the receptor itself checked for quality? (digital image receptors)
check for visible damage to casing/wiring
check if clean (no congealed disinfectant/saliva)
How is the image uniformity checked for quality? (digital image receptors)
expose receptors to an unattenuated x ray beam and check if resulting image is uniform (i.e. should show a consistent shade of grey across the whole image)
How is the image quality checked ? (digital image receptors)
take a radiograph of a test object and assess teh resulting image against a baseline
(receptor damage affecting image) what happens if the phosphor plates have scratches?
white lines
(receptor damage affecting image) what happens if the phosphor plates have cracking from flexing?
network of white lines
(receptor damage affecting image) what happens if the phosphor plates have delamination?
white areas around edge
i.e. separation of phosphor layer from base plate
(receptor damage affecting image) what happens if the solid state sensors have sensor damage?
white squares/straight lines
What damage do the red, yellow, green and blue arrows indicate is wrong with the receptor?
red- scratches to phosphor plate
yellow- cracking from flexing of the phosphor plate
green- delamination of phosphor plate
blue- sensor damage to the solid-state sensor
(receptor damage affecting image) what happens if the film has damage to it?
the damage is often appears as a black mark due to sensitisation of radiographic emulsion
however, may appear white is emulsion is scraped off
What has caused these marks?
Nail scratching
What has caused the marking in the blue circle
delamination
What can be used to check image quality/contrast? And how often should this be carried out
A Step wedge
Can be self made using overlapping layers of lead foil (e.g. 6 different layers of thickness) or provided by manufacturer
Exposed to a normal clinical exposure
This must be compared to a baseline
“must be able to differentiate all 6 steps)
SHOULD be carried out regularly, e.g. every morning
