SPI Practice Test Questions with Accurate Answers

Which of the following do the source and the medium determine? a. duty factor b. frequency c. propagation speed d. axial resolution - ANSWERSd. Axial resolution is affected by all of the following EXCEPT a. frequency b. damping c. spatial pulse length d. focusing - ANSWERSd. Damping in a transducer a. reduces the number of cycles in a pulse and increases the quality factor b. increases the number of cycles in a pulse and increases penetration c. causes poor axial and lateral resolution d. reduces the duty factor and increases the range of transmitted frequencies - ANSWERSd. Far zone beam divergence can be reduced on a single-element transducer by using a. a transducer with a smaller element diameter b. a higher frequency transducer c. a lower frequency transducer or a smaller element diameter d. adjustable focusing - ANSWERSb. The area between the face of an unfocused single-element transducer and the point where the beam starts to diverge is the a. Fraunhofer zone b. refraction zone c. focal zone d. near zone - ANSWERSd. Assuming a fixed frequency, what happens if the diameter of an unfocused transducer is increased? a. the far zone divergence increases b. the penetration decreases c. the length of the near zone increases d. the length of the near zone decreases - ANSWERSc. Which of the following does NOT affect lateral resolution? a. focusing b. element diameter c. frequency d. bandwidth - ANSWERSd. Higher frequency transducers provide a. improved lateral resolution b. smaller Doppler shifts c. improved axial resolution and reduced attenuation d. increased penetration - ANSWERSa. Ultrasound waves that are traveling through a medium consist of a. electromagnetic and radio frequencies b. compressions and refractions c. electromagnetic and ionizing frequencies d. compressions and rarefactions - ANSWERSd. What is the difference between audible sound and ultrasound? a. audible sound waves can travel through a vacuum b. audible sound has a higher frequency c. ultrasound has a higher frequency d. ultrasound waves are ionizing - ANSWERSc. A decrease in the thickness of a piezoelectric element will result in a. a greater pulse duration b. an increase in the propagation speed c. a decrease in the quality factor if the bandwidth decreases d. an increase in the frequency of the transducer - ANSWERSd. The resonant frequency of a pulsed-wave ultrasound transducer is dependent on a. damping b. the backing material c. the thickness of the piezoelectric element and the speed of sound through the piezoelectric element d. the amplitude of the voltage applied to the piezoelectric element - ANSWERSc. The image is brighter at the level of the focal zone. Which of the following controls is best to correct this? a. overall gain b. TGC c. acoustic power d. PRF - ANSWERSb. If the frequency is doubled, a. the duty factor will increase b. the period will double c. the wavelength will double d. the wavelength will be one-half - ANSWERSd. The typical range of pulse repetition frequencies in a pulse-echo ultrasound system is a. 2,000 Hz to 20,000 Hz b. 20 MHz to 200 MHz c. 20,000 Hz to 200,000 Hz d. 1,000 Hz to 2,000 Hz - ANSWERSd. If the number of cycles in a pulse is reduced, a. the pulse repetition frequency is automatically reduced b. the spatial pulse length increases c. the pulse duration is reduced which results in a lower duty factor d. the bandwidth is decreased and the quality factor is increased - ANSWERSc. The minimum reflector separation required to produce separate echoes is a. the spatial resolution of the ultrasound system b. the temporal resolution c. the attenuation coefficient d. the total attentuation - ANSWERSa. As the frequency of sound increases, a. the amount of scatter is increased b. the attenuation decreases c. the amount of scatter decreases d. the penetration increases - ANSWERSa. Which of the following transducers provides the maximum penetration? a. 10.0 MHz b. 7.5 MHz c. 2.25 MHz d. 3.5 MHz - ANSWERSc. The average attenuation of ultrasound energy in the patient is approximately a. 2.0 dB per cm per MHz b. 10.0 dB per cm per MHz c. 5. dB per cm per MHz d. 0.7 dB per cm per MHz - ANSWERSd. If sound from a 3 MHz transducer has 3 dB of attenuation after traveling through 2 cm of tissue, what is the amount of attenuation of sound from a 5 MHz transducer after traveling through 1 cm of the same tissue? a. 5 dB b. 1 dB c. 2 dB d. 2.5 dB - ANSWERSd. The half-value layer or the half-intensity-depth a. is the depth where the intensity is 50% of the originally transmitted intensity b. increases as the frequency of the transmitter increases c. is the range of frequencies contained in an ultrasound pulse d. is the attenuation coefficient in tissue - ANSWERSa. The speed of ultrasound in soft tissue is closest to a. 1.54 mm/sec b. 1540 km/sec c. 1540 mm/sec d. 1540 m/s - ANSWERSd. Ultrasound energy is traveling through the same medium. If the frequency is doubled, the propagation speed is a. quartered b. doubled c. halved d. unchanged - ANSWERSd.