Quality Assurance Flashcards
What is Quality Assurance?
The routine, periodic evaluation of an ultrasound system to guarantee optimal image quality
Medical and legal necessity for every laboratory. The sonographer is responsible for implementing a QA action plan based on objective standards.
What is an Objective Standard/Statement?
Completely unbiased, factual, repeatable, and able to be counted
Not affected by an individual’s previous experience, preference, or taste.
What is a Subjective Standard/Statement?
Influenced by an individual’s experience or beliefs, often unverifiable with concrete facts
Affected by opinion, belief, or assumption and varies from person to person.
What is a Tissue Equivalent Phantom?
Composed of TMM embedded with nylon strings to produce reflections and structures mimicking hollow cysts and solid masses
Similar to soft tissue in speed of sound, attenuation, scattering characteristics, and echogenicity.
What does a Doppler Phantom evaluate?
All modalities of Doppler
Three types: Flow phantoms (most common), vibrating string, and moving belt.
What is the purpose of a Slice Thickness Phantom?
Determines beam profile/elevational resolution
Contains a diffuse scattering plane at an angle to the incident sound beam.
Define Sensitivity in ultrasound.
The ability of a system to display low-level echoes
Assessed by adjusting system controls to change echo brightness.
What is Normal Sensitivity?
Settings that should not vary from one routine evaluation to the next
All pins, solid masses, and cystic structures in the test phantom are accurately displayed.
What is Maximum Sensitivity?
Evaluated with amplification and output power set to maximum practical levels
Depth of tissue-like texture on display is measured.
Fill in the blank: The speed of sound in tissue equivalent phantoms is _______.
1540 m/s
True or False: Subjective standards are factual and repeatable.
False
What is the Dead Zone in ultrasound imaging?
The region close to the transducer where images are inaccurate.
Extends from the transducer to the shallowest depth from which meaningful reflections appear.
What factors influence the thickness of the Dead Zone?
Higher frequency = thinner dead zone, Lower frequency = thicker dead zone.
An acoustic standoff or gel pad can improve imaging of superficial structures.
What can cause an increasingly deeper Dead Zone?
Cracked PZT, detached backing material, longer pulse duration.
These issues affect the accuracy of imaging.
What does Registration Accuracy refer to in ultrasound imaging?
The ability of the system to place reflections in proper positions while imaging from different orientations.
What is Range Accuracy in ultrasound imaging?
The system’s accuracy in placing reflectors at correct depths located parallel to the sound beam.
Errors may be caused by system malfunction or differences in the speed of sound in tissue phantoms.
What is the significance of Depth Calibration?
It evaluates the accuracy of reflector depth positioning in A-mode, M-mode, B-mode, and 2D imaging.
What does Lateral Resolution refer to?
The system’s ability to place echoes in their correct position when the reflectors are perpendicular to the sound beam.
How is Uniformity/Compensation evaluated?
By measuring the width of reflections on the display created by point targets in the phantom.
What is the purpose of Digital Calipers in ultrasound?
Used to measure distances of structures during exams, evaluated in both vertical and horizontal directions.
What does the system’s Hardcopy Output refer to?
The ability to produce printed images from the ultrasound system.
What is Gray Scale Dynamic Range?
The system’s ability to display similar reflectors with echoes of equal brightness.
True or False: Adjusting brightness or contrast of a monitor should alter the image on all output devices.
False.
Adjusting brightness or contrast only alters the image on the display.
What are the main components assessed in QA requirements?
System components, repairs, preventative maintenance, record keeping
These components ensure the quality of the system is maintained.
What is a primary goal of QA in system operation?
Guarantee proper operation of the system
This goal helps ensure that the system functions as intended.
List three QA goals.
- Detect gradual changes
- Minimize downtime
- Reduce the number of non-diagnostic exams
These goals contribute to the overall efficiency and reliability of the system.
What does QA stand for?
Quality Assurance
QA involves systematic processes to ensure products or services meet specified requirements.
Fill in the blank: QA devices include a _______ phantom.
Tissue equivalent
Tissue equivalent phantoms are used to simulate human tissue in QA testing.
What measures does the tissue equivalent phantom assess?
- Gray scale
- TGC (normal and Max)
- A.O.
- Foci
- Calipers
- Axial and Lateral Res.
These measures are crucial for evaluating the performance of imaging systems.
What is the purpose of using a Doppler phantom in QA?
To use a constant instrument that measures all Doppler modalities
This allows for comprehensive testing of Doppler ultrasound capabilities.
True or False: QA methods should test under undefined conditions.
False
Testing under known, defined conditions ensures accuracy and reliability.
What types of phantoms are used in QA methods?
- Moving belt
- Flow phantom
- Beam profile/slice thickness phantom
These phantoms help in assessing various aspects of imaging systems.
What does the beam profile/slice thickness phantom measure?
Elevational Resolution
This measurement is important for determining the clarity of images produced by the imaging system.
Fill in the blank: To ensure accurate measurements, image in an _______ environment.
Identical
Imaging in identical environments minimizes variability in test results.
