Quality Assurance

Question 1

Define QA.

Answer 1

Quality assurance refers to the systematic way by which a service can be monitored and evaluated, to ensure a specified standard is being met, and is a legal requirement in diagnostic imaging.

Question 2

List 4 of the concepts of QA

Answer 2

• Radiation dose optimisation
• Quality of care (service, environment, safety)
• Equipment performance
• Image quality (resolution, contrast, reject analysis)
• Quality of diagnosis (diagnostic sensitivity & specificity, reporting times)

Question 3

What are the wider frameworks that regulate QA?

Answer 3

• Care quality commission (CQC)
• Royal college of Radiologists (RCR)
• Health and safety executive (HSE)
• Institute of physics and engineering in medicine (IPEM)

Question 4

Describe the 4 QA stages in the life cycle of an X-ray system

Answer 4

• Critical examination: Ensures all safety features work correctly
• Acceptance: Checks that the contractor has supplied all the specific equipment
• Commissioning: Carried out by medical physics to ensure equipment is ready for use
• Routine performance: Carried out throughout the life of the equipment

Question 5

Why is it important that QA tests are documented?

Answer 5

• So that they can be used as evidence and be presented to HSE/CQC inspectors on request
• Enables ALARA/P
• Ensures patient safety
• Compliance to legislation
• Identifies deterioration in equipment

Question 6

List the 6 QA test carried out by radiographers.

Answer 6

• X-ray/Light beam alignment and centring
• Light beam/Bucky centring
• DRLs
• Lead apron screening
• Radiation output repeatability and reproducibility
• Image receptor quality/Uniformity

Question 7

What are the 5 QA checks carried out by MPEs?

Answer 7

• Tube potential
• Luminescence of image displays (variance between monitors)
• Calibration
• Spatial resolution
• Radiation output repeatability and reproducibility

Question 8

What are 3 differences and 1 similarity between Suspension Level Action and Remedial Level Action?

Answer 8

• With Remedial action, the equipment can be used whereas in Suspension action the equipment has to be taken out of service
• The RPA/MPE must be informed of the results of a suspension action but it is the QA radiographer that is informed in remedial action
• The engineer must be contacted as soon as possible with a suspension action and with a remedial action they can attend at the next appointment (less urgency)
  -There must be instructions left for staff in the case of Remedial and adequate signage of room and/or components in Suspension

-In both actions, repeat tests must be carried out on the equipment to ensure that there was no error in interpretation

Question 9

List and explain the 3 daily checks and maintenance

Answer 9

• Tube warmup: Carried out multiple times a day after periods of being stationary
• Air calibration: Involves performing a CT scan, without a subject or phantom between the source and detector, so the detectors are irradiated and attenuated by the X-ray beam
• Basic overview of table/gantry: Ensures that there are no loose parts or artefacts and the table is clean and moves smoothly

Question 10

Explain the Hounsfield Uniformity test

Answer 10

This is when a large water equivalent cylinder containing cylindrical rods that assess the CT number of different materials (air, delrin, acrylic resin, nylon, polypropylene, water) is used.

Question 11

What materials are the cylindrical rods made of in the TOS phantom (A-F)?

Answer 11

A: Air
B: Delrin 
C: Acrylic resin
D: Nylon
E: Polypropylene
F: Water

Question 12

Water Phantom Noise Test

Answer 12

• Ensures uniformity through phantom with 1 overall CT number
  (e.g. Water: HU= 0)
• 5 measures of s. d. taken at specified points across image
• Detectable by eye