QA/QC Notes

Quality Assurance (QA) and Quality Control (QC)

Quality Assurance (QA)

• Deals with patients and services, focusing on the patient's overall experience.

• Example: A patient’s experience from start to finish.

Continuous Quality Improvement (CQI)

• Focuses on improving processes within which employees function as team members for patient care.

• All employees must be involved in the improvement process.

• Example: How a patient’s experience was from the beginning to the end of their hospital stay.

The Joint Commission (TJC)

• Ensures high-quality services and care in healthcare organizations.

• TJC requires QA/QC programs.

Quality Control (QC) Overview

• Product-oriented, focusing on defect identification.

• Reactive approach using corrective tools.

• Specific team responsibility.

• Monitors radiology instrumentation, equipment, and artifacts; ensures radiographic procedures are performed safely to provide the highest quality images.

• Each new piece of equipment should be tested prior to use.

• Required by law to maintain license for room/department

Process of a QC Program:

1. Acceptance testing

2. Performance monitoring

3. Error maintenance

• Annual evaluations are required.

Acceptance Testing

• Performed before machine installation or major repairs.

• Determines if equipment is working properly.

Performance Maintenance

• Tests performed daily, monthly, quarterly, and annually to ensure equipment functions properly and to avoid failure.

Error Maintenance

• Occurs due to poor equipment performance.

• Corrective action must be taken.

QC Documentation

• Consistent and accurate records are essential.

• Unacceptable results must be documented with a corrective action plan.

Physicist’s Annual Testing (Partial List)

• Noise, Spatial Resolution, Contrast Resolution

• Dose Response/Signal, Dynamic Range (Exposure Linearity)

• Detector & Dose Calibration, AEC & kVp Testing

• Plate Reader Calibration, Residual Signal Erase, Image Artifacts

• Repeat Analysis, Uniformity Test

• Beam Filtration, Collimation

• Monitor Display Function, Luminance & Reflection Testing

Workstations

• Require regular QC testing.

• Radiologist's viewing stations have higher quality than technologist's.

• Assessment for Display Performance for Medical Imaging Systems: document for daily, monthly/quarterly tests.

SMPTE Test

• Used to determine if contrast/brightness settings on monitor are acceptable.

• Observation of 5% and 95% luminance patches to identify deviations in luminance adjustments.

Workstation Calibration – AAPM TG 18 Test

• Commonly called TG18-QC.

• Pattern used for overall assessment of a monitor’s adjustment & calibration.

Photometer

• Tool to measure light intensity (luminescence) on a workstation monitor.

Elements of Radiographic Systems QC Program

• Filtration, Collimation, Focal spot size

• Spatial Resolution

• PSP Imaging Plate Uniformity & Erasure Thoroughness

• kVp calibration, Exposure timer accuracy

• Exposure linearity & reproducibility

Filtration

• State requires minimum total filtration of $2.5$ mm Al.

• Measured by checking HVL, annually or with tube/housing changes.

Collimation/Beam Restriction Test

• Beam alignment check relative to the image receptor (IR).

• PBL (positive beam limitation) automatically collimates to film size.

Focal Spot

• Small focal spot: needed when spatial resolution is needed.

• Large focal spot: short exposure time priority, more photons emitted.

Spatial Resolution

• Ability to render small objects on an image.

• Smaller pixel size = better spatial resolution.

PSP Uniformity Test

• Assesses uniformity of signal from exposed imaging plate (IP).

• Detects artifacts; requires regular cleaning of cassettes/IP.

PSP Imaging Plate Erasure Thoroughness

• Ensures minimal residual signal (ghosting).

• White light is used to delete trapped energy from IP.

AEC

• Method for setting exposure factors to ensure a quality radiographic image.

Exposure Timer Accuracy

• Exposure Linearity: Constant radiation output for various mA and exposure time combinations. Example: If $70kVp$ and $50 mA$, $1$ sec. ($50mAs$) produces $50mR$, then $70kVp$ and $100 mA$, $0.5$ sec ($50 mAs$) should produce $50mR$.

• Exposure Reproducibility: Tests kVp, mA, and time in successive exposures.

Protective Apparel Test

• Aprons, gonadal shields, gloves checked for defects under fluoroscopy.

Recognition & Reporting Malfunctions

• Technologist's responsibility to report malfunctions.

• Equipment failure requires repair and physicist recalibration.

Fluoro QC

• Fluoro exams = high pt. dose

• Entrance skin exposure (ESE) averages fluoro exam is $3$ to $5$ rads/min

Exposure Rate

• State law: ESE shall not exceed $10R/min$ = normal fluoro.

• ESE allowed up to $20R/min$ = interventional procedures.