SPI ARDMS EXAM QUESTIONS AND ANSWERS/STUDY GUIDE
LATEST UPDATE
What type of wave is sound? Correct Ans ~ mechanical and longitudinal
The frequency ranges for ultrasound are: Correct Ans ~ >20 kHz
The speed of sound in soft tissue is: Correct Ans ~ 1540 m/s
which of the following transducers fires the elements in groups?
A. Linear sequenced array
B. Phased array
C. Continuous-wave transducer
D. Single-element transducer Correct Ans ~ A
Enhancement is caused by** Correct Ans ~ weakly attenuating structures
wavelength in material having a propagation speed of 1.5mm/µs w/transducer frequency of 5.0
MHz is: ** Correct Ans ~ .3mm 1.5mm/µs / 5MHz =.3mm
An ultrasound transducer converts ** Correct Ans ~ electrical energy into mechanical energy
Media lowest attenuation to highest: ** Correct Ans ~ Fat, Muscle, Bone, Air
Media propagation speed from lowest to highest: ** Correct Ans ~ Air, Fat, Muscle, Bone
If the frequency doubles, what happens to the wavelength? ** Correct Ans ~ Decreases by
1/2 (inversely related)
What happens to intensity if amplitude of signal is 1/2? ** Correct Ans ~ Quartered
% of time that sound is on Correct Ans ~ Duty Factor
A 3 dB gain would indicate an increase in intensity of ______ times. ** Correct Ans ~ 2
times
Ignoring the effects of attenuation, the intensity of the ultrasound beam is usually greater at the
focal zone because of. ** Correct Ans ~ smaller beam diameter
Attenuation denotes. ** Correct Ans ~ Progressive weakening of the sound beam as it travels
which of the following has the lowest intensity **
A. SPTP
B. SATP
C. SPTA
, D. SATA Correct Ans ~ D =LOWEST A=HIGHEST**
definition of the beam uniformity ratio?** Correct Ans ~ Spatial peak intensity divided by
spatial average (SP/SA)
Continuous-wave doppler has a duty factor of: Correct Ans ~ 100% (always on)
spatial pulse length is a product of the _____ & the number of _______ in a pulse? Correct Ans
~ wavelength & Cycles
If the gain of an amplifier is 18 dB, what will the new gain setting be if the gain setting is
reduced by one-half? ** Correct Ans ~ 15dB (1/2=-3dB therefore, 18dB-3dB=15dB)
True or False: SPTP is always equal to or greater than SPTA ** Correct Ans ~ True
If the amplitude of a wave is increased threefold, the power will: ** Correct Ans ~ Increase
NINEfold (amp squared)
ultrasound attenuates an average of ____ dB/cm of travel for each megahertz of frequency. **
Correct Ans ~ .7
If the intensity transmission coefficient is 0.74, the intensity reflection coefficient will be: **
Correct Ans ~ .26 (IRC & ITC must =100)
Acoustic impedance is a product of: ** Correct Ans ~ speed of sound in tissue & density of
the tissue
reflector whose size is smaller than the wavelength ** Correct Ans ~ Rayleigh Scattering
Total attenuation of a 3.5MHz pulse after passing thru 2cm of soft tissue?** Correct Ans ~
3.5dB
The thinner the piezoelectric element: ** Correct Ans ~ the higher the frequency
The unit for impedance is ________. Correct Ans ~ Rayl
A sound beam encounters an interface at a 90* angle. If the speed of sound in the first tissue is
1540m/s & speed of sound in second tissue is 1450 m/s, what is approximate angle of beam
transmission? Correct Ans ~ 90* (no refraction)
A decibel describes the: Correct Ans ~ RATIO of 2 sound intensities
Attenuation coefficient of sound in soft tissue can be defined by what equation? ** Correct Ans
~ frequency/2 (1/2 of freq)
LATEST UPDATE
What type of wave is sound? Correct Ans ~ mechanical and longitudinal
The frequency ranges for ultrasound are: Correct Ans ~ >20 kHz
The speed of sound in soft tissue is: Correct Ans ~ 1540 m/s
which of the following transducers fires the elements in groups?
A. Linear sequenced array
B. Phased array
C. Continuous-wave transducer
D. Single-element transducer Correct Ans ~ A
Enhancement is caused by** Correct Ans ~ weakly attenuating structures
wavelength in material having a propagation speed of 1.5mm/µs w/transducer frequency of 5.0
MHz is: ** Correct Ans ~ .3mm 1.5mm/µs / 5MHz =.3mm
An ultrasound transducer converts ** Correct Ans ~ electrical energy into mechanical energy
Media lowest attenuation to highest: ** Correct Ans ~ Fat, Muscle, Bone, Air
Media propagation speed from lowest to highest: ** Correct Ans ~ Air, Fat, Muscle, Bone
If the frequency doubles, what happens to the wavelength? ** Correct Ans ~ Decreases by
1/2 (inversely related)
What happens to intensity if amplitude of signal is 1/2? ** Correct Ans ~ Quartered
% of time that sound is on Correct Ans ~ Duty Factor
A 3 dB gain would indicate an increase in intensity of ______ times. ** Correct Ans ~ 2
times
Ignoring the effects of attenuation, the intensity of the ultrasound beam is usually greater at the
focal zone because of. ** Correct Ans ~ smaller beam diameter
Attenuation denotes. ** Correct Ans ~ Progressive weakening of the sound beam as it travels
which of the following has the lowest intensity **
A. SPTP
B. SATP
C. SPTA
, D. SATA Correct Ans ~ D =LOWEST A=HIGHEST**
definition of the beam uniformity ratio?** Correct Ans ~ Spatial peak intensity divided by
spatial average (SP/SA)
Continuous-wave doppler has a duty factor of: Correct Ans ~ 100% (always on)
spatial pulse length is a product of the _____ & the number of _______ in a pulse? Correct Ans
~ wavelength & Cycles
If the gain of an amplifier is 18 dB, what will the new gain setting be if the gain setting is
reduced by one-half? ** Correct Ans ~ 15dB (1/2=-3dB therefore, 18dB-3dB=15dB)
True or False: SPTP is always equal to or greater than SPTA ** Correct Ans ~ True
If the amplitude of a wave is increased threefold, the power will: ** Correct Ans ~ Increase
NINEfold (amp squared)
ultrasound attenuates an average of ____ dB/cm of travel for each megahertz of frequency. **
Correct Ans ~ .7
If the intensity transmission coefficient is 0.74, the intensity reflection coefficient will be: **
Correct Ans ~ .26 (IRC & ITC must =100)
Acoustic impedance is a product of: ** Correct Ans ~ speed of sound in tissue & density of
the tissue
reflector whose size is smaller than the wavelength ** Correct Ans ~ Rayleigh Scattering
Total attenuation of a 3.5MHz pulse after passing thru 2cm of soft tissue?** Correct Ans ~
3.5dB
The thinner the piezoelectric element: ** Correct Ans ~ the higher the frequency
The unit for impedance is ________. Correct Ans ~ Rayl
A sound beam encounters an interface at a 90* angle. If the speed of sound in the first tissue is
1540m/s & speed of sound in second tissue is 1450 m/s, what is approximate angle of beam
transmission? Correct Ans ~ 90* (no refraction)
A decibel describes the: Correct Ans ~ RATIO of 2 sound intensities
Attenuation coefficient of sound in soft tissue can be defined by what equation? ** Correct Ans
~ frequency/2 (1/2 of freq)
