Quality Assurance Flashcards
What is Quality Assurance (QA)
A systematic way by which a service can be monitored and evaluated, to ensure a specified standard is being met.
A legal requirement in diagnostic imaging
Key concepts of QA (5)
Radiation dose optimisation Image quality - resolution, contrast, no artefacts, reject analysis Equipment performance quality of care quality of diagnosis
QA documentation states (6)
What tests have to be done
How the tests should be done
How often the tests should be done
How the test results are recorded and analysed
Acceptable margin of deviation from the standard is
What to do if a test is failed
How is QA regulated (3)
IR (ME) R 2017
IRR 2017
Wider frameworks e.g. Care quality commission, royal college radiologist, heal and safety executive and institute of physics and enginereering in medicine
4 QA stages in the life cycle of an x-ray system
- critical examination
- acceptance
- commissioning
- routine performance
Routine QA test carried out by radiographers (6)
X-ray/Lightbeam alignment and centring Lightbeam/Bucky centring Dose reference levels (DRLs) Lead apron screening Radiation output repeatability and reproducibility Image receptor quality/uniformity
Routine QA tests carried out by medical physicists (5)
Tube potential
Radiation output repeatability and reproducibility
Spatial resolution
Luminescenes of image displays and variance between monitors
Calibration
Action levels
QA test result displays a deviation from the recognised baseline, action may need to be taken
What determines action to be taken (4)
The degree of deviation
the significance of the additional hazard
the degree of impairment in image quality
result in a dose to a patient that is “much greater than that intended”
Remedial level action (4)
Action is required but equipment can be used in the meantime
Always repeat the test to ensure there was no error in interpretation
Inform QA radiographer
Request that the engineer checks on their next visit
Suspension level action (6)
Equipment must be taken out of service immediately
Repeat test in case of misinterpretation, ask colleague to double check figures
Record the results
Inform senior staff/QA radiographer
RPA/MPE informed
Engineer contacted
X-ray/lightbeam alignment and centring (2)
Designed to evaluate collimator light field congruence, and to ensure accurate x-ray beam alignment
Brass plate contains an etched scale in cms and rectangle for checking beam collimation
X-ray alignment and centring procedure (7)
performed every 1-2 months
place IR or Digital receptor onto tabletop, with brass plate on top
SID = 100cm
centre to the cross hairs of the test tools
collimate to the etched rectangle
exposure of 60kvp and 2 mas
open the collimation to the entire test tool and expose again
x-ray light beam and centring action levels (2)
remedial level action for this test is misalignment of 1cm
suspension level action for this test is a misalignment of 3cm
Screening lead aprons (2)
done under x-ray or fluoro guidance
lead aprons must be routinely checked for cracks
Resolution test (3)
Object made out of metal and perspex
Slits in the metal are of decreasing thickness and are called line pairs
5 LP per mm would be very high resolution
Viewing monitor geometric test
Simple test checks for any distortion within the test tools
CT QA procedures: Daily checks and maintenance (3)
Tube warm up
Air calibration
Basic overview of the mechanics of the table/gantry
Hounsfield uniformity test (2)
Large water equivalent cylinder filled with water and contains cylindrical rods for assessing the CT number of different materials
Each of these materials are designed to have a HU similar to a specific body component
water phantom noise test (2)
test to ensure uniformity through a phantom with one overall ct number
allows us to detect and control noise on an image
