QAQC

Quality Assurance (QA)

Planned and systematic actions to ensure a product or service meets quality requirements.

Quality Control (QC)

Part of QA focused on monitoring and maintenance of equipment performance.

Quality Assurance (QA)

Focuses on the people and process to prevent defects.

Quality Control (QC)

Focuses on identifying and correcting defects.

Quality Assurance (QA)

Proactive quality activity.

Quality Control (QC)

Reactive quality activity.

Quality Assurance (QA)

Usually performed by management and administrators.

Quality Control (QC)

Usually performed by technologists, physicists, engineers.

Acceptance testing, routine performance monitoring, and maintenance.

QC Program Three Steps

Acceptance testing

Initial QC test of new or repaired radiologic equipment to verify performance within manufacturer specifications before clinical use.

Medical physicist

Professional primarily responsible for establishing and overseeing the QC program in imaging facilities.

Positive Beam-Limiting (PBL) Collimator

Automatic collimator that matches the x-ray beam to the size of the image receptor to limit unnecessary radiation.

Should be 31 °C (87 °F) to ensure proper removal of residual chemicals from film.

Wash water temperature

Film analysis

Monthly review categorizing radiographs as good, poor, or reject to identify imaging quality problems.

Processor sludge

Deposits of chemical residue and debris on processor rollers caused by high-throughput, high-temperature operation.

Main goal of QA in radiology

Ensures consistent production of high-quality diagnostic images with minimum exposure to patients and personnel.

Reduce radiation exposure to patients and staff.

Reduce costs by reducing repeat examinations.

Improve department efficiency.

Ensure compliance with regulations and accreditation standards.

Objectives of QA

Food and Drug Administration (FDA)

US federal agency that regulates radiation-emitting products.

Nuclear Regulatory Commission (NRC)

Sets standards for safe use of radiation-producing equipment.

International Commission on Radiological Protection (ICRP)

Publishes recommendations on radiation protection.

International Electrotechnical Commission (IEC)

Publishes performance standards for radiologic equipment.

American College of Radiology (ACR)

Publishes guidelines on QA in diagnostic radiology.

QA Program

Systematic approach to quality involving: organization, data collection, evaluation, and corrective action.

Organization phase of QA

Step involving definition of responsibilities, staff training, and assignment of QA coordinator.

Data collection phase of QA

Step involving gathering data on equipment performance and image quality.

Evaluation phase of QA

Step involving comparison of data to established standards.

Corrective action phase of QA

Step involving implementing measures to address deficiencies.

Level I QC

Checks and adjustments performed by technologists on a daily basis.

Level II QC

More extensive tests performed by medical physicists or engineers quarterly or semiannually.

Level III QC

Specialized tests performed by service engineers after repairs or major changes.

Scheduled maintenance

Refers to routine procedures that are performed usually weekly or monthly.

Preventive maintenance

A planned program of parts replacement at regular intervals.

Non-scheduled maintenance

Unplanned repair work performed when equipment fails unexpectedly.

Reproducibility of exposure

QA test ensuring consistency of x-ray output at same exposure settings.

±5%

Acceptable variance for reproducibility of exposure.

Annually

Frequency of reproducibility of exposure test.

Linearity of exposure

QA test ensuring consistent output for different combinations of mA and time producing same mAs.

±10%

Acceptable variance for linearity of exposure.

Annually

Frequency of linearity of exposure test.

kVp accuracy test

QA test ensuring kVp accuracy compared to indicated kVp.

±5%

Acceptable variance for kVp accuracy.

Annually

Frequency of kVp accuracy test.

Beam uniformity test

QA test ensuring uniformity of x-ray beam intensity across the field.

Annually

Frequency of beam uniformity test.

Light field–radiation field congruence

QA test ensuring field size at the image receptor matches the collimator setting.

±2% of SID

Maximum allowed misalignment for light field–radiation field congruence.

Annually

Frequency of light field–radiation field congruence test.

Perpendicularity test

QA test ensuring the x-ray beam is aligned perpendicular to the image receptor.

Annually

Frequency of perpendicularity test.

X-ray beam–Bucky tray alignment

QA test ensuring proper alignment of the x-ray tube, beam, and image receptor.

Annually

Frequency of x-ray beam–Bucky tray alignment test.

Filtration test

QA test ensuring total filtration meets minimum standards.

2.5 mm Al equivalent

Minimum total filtration for equipment above 70 kVp.

Annually

Frequency of filtration test.

AEC performance test

Test ensuring exposure is terminated at proper time in AEC systems.

±10%

Acceptable variance for AEC performance.

Annually

Frequency of AEC performance test.

Backup timer test

Test ensuring AEC produces correct exposure regardless of patient thickness.

Annually

Frequency of backup timer test.

Grid alignment test

Test ensuring grid lines are not visible in image.

Annually

Frequency of grid alignment test.

CT QC tests

Tests ensuring CT number accuracy, slice thickness accuracy, and spatial resolution.

Annually

Frequency of CT QC tests.

Mammography QC test

Test ensuring mammography units meet spatial resolution and contrast standards.

Annually

Frequency of mammography QC test.

Fluoroscopy QC test

Test ensuring fluoroscopic units meet maximum exposure rate limits.

Annually

Frequency of fluoroscopy QC test.

Safelight test (fog test)

Darkroom test using film with half covered to check for light leaks.

0.05 OD

Maximum acceptable optical density increase from safelight fog.

Semiannually

Frequency of safelight test.

Coin test

Test using coin on film exposed to safelight to check for fogging.

Semiannually

Frequency of coin test.

Processor QC

Test to ensure processor maintains consistent film density, contrast, and base plus fog.

Daily

Frequency of processor QC testing.

Processor temperature test

Test to check processor temperature stability.

±0.5°C

Acceptable developer temperature variation.

Daily

Frequency of processor temperature test.

Sensitometric control test

Test to monitor replenishment rates and chemical activity.

Daily

Frequency of sensitometric control test.

Clearing test

Test ensuring fixer removes undeveloped silver halide crystals.

Weekly

Frequency of clearing test.

Digital imaging QC

Program ensuring image quality in digital systems by checking monitor resolution, luminance, and contrast.

Monthly

Frequency of digital imaging QC.

SMPTE pattern

Test pattern used for QC of monitors.

Printer QC

Test ensuring printer reproduces images accurately.

Monthly

Frequency of printer QC.

Pinhole camera

Focal spot test that is difficult to use and requires excessive exposure time

Star pattern

It is easy to use but has significant limitations for focal- spot sizes less than 0.3 mm.

Slit camera

The standard for measurement of effective focal-spot size.

±50% for focal spots <0.8 mm, ±40% for 0.8–1.5 mm, ±30% for >1.5 mm

Acceptable focal spot size variance.

Phototimer

AEC device that uses a light-sensitive detector to terminate the exposure at proper image receptor dose.

6 seconds or 600 mAs

Backup timer should terminate at ___________, whichever occurs first

Intensifying screen

Convert x-ray photons to visible light to expose film, reducing patient dose.

Cleaned at least every other month with manufacturer-recommended cleaner and soft lint-free cloth.

Intensifying screen cleaning schedule

Screen-film contact test

Wire-mesh radiograph used to check for areas of blur indicating poor contact.

Once or twice a year

Frequency for screen-film contact test.

Annually

Frequency for protective apparel QC.

View box intensity should be at least 1500 cd/m² with no more than ±10% non-uniformity.

Illuminator QC standard

Annually

Frequency for illuminator QC.