MOD 6 - Quality Control Tests

Quality Control in Imaging

the monitoring, testing and maintenance of the x-ray equipment to ensure it's working optimally to minimize patient dose and ensure high quality images

Total Quality Management (TQM)

• all members of an organization participate in improving processes, products, services and the culture in which they work

• everyone in the medical imaging department is involved in one way or another with QA and QC

Continuous Quality Improvement (CQI)

focusses on improving processes or systems in place

Quality Assurance (QA)

• the planned and systematic actions that provide confidence that a diagnostic x-ray facility will produce high-quality images with minimum exposure of patients and it's personnel

• Features Include:

  • Information Quality = provides diagnostic images and info

  • Clinical Efficiency = provides diagnostic images quickly and efficiently

  • Patient Dose = ALARA

Equipment Testing Step Process

1. Acceptance Testing and Establishing a Baseline

1. done before the equipment is put to use (eg. new equipment)

2. conducted by a physicist (who has no relation/bias towards the equipment)

3. calibrated and a reference image is stored

4. takes around 8-10 hrs

2. Routine Performance 

daily inspections of equipment to weekly, monthly and annual testing and inspections

3. Error Correction

a decision tree that answers the following

1. A repeat of the test to confirm

2. What to do if repeated test confirms performance failure

3. what to do if test fails only marginally 

4. what to do if the test shows a history of failure 

5. what to do if the test fails substantially

4. Evaluation

if an equipment has a +/- 10% acceptable test limit in place, the equipment is deemed unsafe for patient use, if repaired it needs to be tested again before use

Implementation of a QA Program

1. list of personnel and their duties

2. policies to minimize dose to personnel

3.  policies to minimize dose to patients

4. Guidelines to QC Tests

5. Policies to acquire new X-ray equipment

6. Policies for Record Keeping  

QC Team

• owner of the facility = primarily responsible

• radiologist = provides oversight

• department supervisor/ QC coordinator = plan and manages testing

• medical physicist = plans and manages testing, performs annual testing, reviews and evaluates QC, logs QC, sets acceptance limits

• biomedical engineers = performs annual testing, repairs damaged equipment

• technologists = performs daily, weekly, monthly testing, documents results in QC logs 

Documentation

documented in the QC logbook

Format of a QC Test

1. Aim = overall goals of the test

2. Equipment = test tools/equipment needed for this test

3. Method = specific steps to conduct this test

4. Frequency = how often is the test completed

5. Data Record Keeping = QC log

6. Tolerances = setting max/min limits

7. Action = what to do after the results show equipment issues

Testing Tools

• All-in-One Tool = CR Testing

• Collimation and Beam Alignment Test Tool =

• Multi-Parameter Measuring Device = measures kVp, dose, pulse rate and mA linearity

• Acrylic Sheets = to test AEC

• Line Pair Test Pattern = to assess focal spot size and SR

• LEEDS Test Phantom = to test contrast and resolution

Determination of Testing Frequency

• If equipment is showing significant signs of wear and tear between testing, then testing frequency may need to increase.

• QC tests should not be less frequent if the QC tests always show stable results

Diagnostic Accreditation Program (DAP)

• a governing body assigned to monitor for upkeep and adherence to a Quality Standard

• regulated by College of Physicians and Surgeons of British Columbia