RVT Ultrasound Physics and Instrumentation

Question 1

The piezoelectric effect in ultrasound transducers refers to the ability of certain crystals to:

Accepted Answer

Convert electrical energy into mechanical (sound) energy and vice versa

Answer

Amplify returning echo signals without distortion

Answer

Filter out low-frequency noise from the Doppler signal

Answer

Measure blood flow velocity independent of angle

Question 2

Which relationship best describes how ultrasound frequency affects axial resolution?

Accepted Answer

Higher frequency produces shorter wavelengths and better axial resolution

Answer

Lower frequency produces shorter wavelengths and better axial resolution

Answer

Frequency has no effect on axial resolution

Answer

Higher frequency improves lateral resolution but worsens axial resolution

Question 3

The Nyquist limit in pulsed-wave Doppler is defined as:

Accepted Answer

Half the pulse repetition frequency (PRF)

Answer

Twice the pulse repetition frequency (PRF)

Answer

The maximum tissue depth that can be imaged

Answer

The minimum detectable blood flow velocity

Question 4

Acoustic impedance (Z) of a tissue is determined by:

Accepted Answer

The product of tissue density and the speed of sound in that tissue

Answer

The ratio of transmitted frequency to reflected frequency

Answer

The depth of the structure divided by the time of flight

Answer

The attenuation coefficient multiplied by path length

Question 5

Ultrasound attenuation in soft tissue is approximately:

Accepted Answer

0.5 dB/cm/MHz

Answer

5 dB/cm/MHz

Answer

0.05 dB/cm/MHz

Answer

2 dB/cm/MHz

Question 6

The assumed propagation speed of sound used by diagnostic ultrasound equipment in soft tissue is:

Accepted Answer

1,540 m/s

Answer

1,000 m/s

Answer

340 m/s

Answer

3,300 m/s

Question 7

Which of the following transducer types produces a sector-shaped image that is useful for accessing small acoustic windows?

Accepted Answer

Phased array

Answer

Linear array

Answer

Curvilinear array

Answer

Annular array