Quality Assurance and Phantoms Flashcards
7 cards from real ARDMS SPI practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Quality Assurance and Phantoms flashcards as text
A tissue-mimicking phantom contains hyperechoic spherical masses. These targets are primarily used to test which system performance parameter?
Answer: Contrast resolution for high-reflectivity lesions
Hyperechoic spherical targets surrounded by uniform background material test the system's ability to detect and resolve high-amplitude echoes against background speckle.
Which QA measurement describes the shortest distance from the transducer face at which the system can display accurate image information?
Answer: Dead zone
The dead zone is the region immediately adjacent to the transducer face where the system cannot detect echoes due to the ring-down artifact from the transmitted pulse.
In a QA protocol for Doppler systems, a string phantom or flow phantom is used. What specific parameter does a string phantom test?
Answer: Velocity accuracy and angle dependence of Doppler measurements
A string phantom moves a target at a known velocity, allowing the sonographer to verify that the system accurately reports Doppler-derived velocity at various beam-to-target angles.
When assessing depth of penetration during QA, what endpoint is typically used to define maximum usable depth?
Answer: The deepest depth at which a uniform speckle pattern is still visible
Penetration depth is defined as the greatest depth at which the speckle pattern from the tissue-mimicking material is still discernible above noise.
A QA test finds that the dead zone has increased significantly from the baseline value. Which clinical implication is most important?
Answer: Superficial structures may not be visualized accurately
An enlarged dead zone means structures immediately beneath the transducer face may be missed or misrepresented, which is critical for superficial examinations.
Which of the following best explains why QA phantoms must be stored at a controlled temperature?
Answer: Speed of sound in the phantom changes with temperature, affecting distance accuracy
The speed of sound in phantom material is temperature-dependent; significant deviation from calibration temperature changes the apparent distances of internal targets.
Which transducer performance defect is most likely to produce a focal band of absent or reduced echoes at a specific depth in a QA phantom image?
Answer: A dead row of elements in a 1.5D array
A dead row of elements in a multidimensional array creates a shadow band or region of signal dropout at the depth where that row's contribution is critical.