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.