ARDMS SPI Quality Assurance and Phantoms 2

Question 1

Which phantom structure is used to assess axial resolution in an ultrasound system?

Accepted Answer

Closely spaced wire targets aligned along the beam axis

Answer

Wire targets placed at known separations along the beam axis allow measurement of the minimum resolvable distance in the axial direction.

Question 2

What does the uniformity test on a QA phantom primarily evaluate?

Accepted Answer

Consistency of gray-scale brightness across the image field

Answer

Uniformity testing checks that the image brightness is homogeneous throughout the field, revealing gain, TGC, or transducer element dropouts.

Question 3

A QA test reveals that the on-screen distance measurement reads 5.2 cm for a structure the phantom certifies as 5.0 cm. What does this indicate?

Accepted Answer

Caliper or distance accuracy error exceeding acceptable tolerance

Answer

A 4% error in distance measurement suggests a calibration issue with the system's speed-of-sound assumption or caliper circuitry.

Question 4

Which parameter is assessed when using anechoic spherical targets of progressively smaller diameter within a tissue-mimicking phantom?

Accepted Answer

Contrast resolution

Answer

Detecting anechoic spheres against a uniform background tests contrast resolution, which reflects the system's ability to distinguish subtle echo-amplitude differences.

Question 5

Which material property of a tissue-mimicking phantom most directly simulates the acoustic attenuation of soft tissue?

Accepted Answer

Attenuation coefficient of approximately 0.5 dB/cm/MHz

Answer

Soft tissue has an attenuation coefficient of ~0.5 dB/cm/MHz, and QA phantoms are formulated to match this value for realistic signal depth behavior.

ARDMS SPI - ARDMS Sonography Principles and Instrumentation Practice Test

ARDMS SPI - ARDMS Sonography Principles and Instrumentation Practice Test

ARDMS SPI Quality Assurance and Phantoms 2