SPI ULTRASOUND REGISTRY REVIEW
QUESTIONS WITH ACCURATE
ANSWERS
SPL - ANSWERSwavelength x # of cycles
With phased array transducers, the transmitted sound beam is steered by -
ANSWERSVarying the timing of pulses to the individual piezoelectric elements
What type of wave is sound? - ANSWERSmechanical and longitudinal
The Frequency ranges for Ultrasound are: - ANSWERS> 20,000 Hz (20kHz)
The speed of sound in soft tissue is: - ANSWERS1540 m/s
Linear sequence Array - ANSWERStransducer that fires the elements in groups
Unit for Wavelength - ANSWERSis millimeters
Enhancement is caused by - ANSWERSweakly attenuating structures (such as a cyst)
The wavelength in a material having a propagation speed of 1.5 mm/us employing a
transducer frequency of 5.0 MHz is: - ANSWERS0.3 mm Wavelength= c/f = 1.5mm/us ÷
5MHz = 0.3mm
An ultrasound transducer converts: - ANSWERSelectrical energy into mechanical
energy and vice versa
The order of attenuation, from the lowest attenuation to highest: - ANSWERSfat,
muscle, bone, air
Propagation Speed from the lowest to highest: - ANSWERSair, fat, muscle, bone
If the frequency doubled, what to wavelength? - ANSWERSDecrease by one half/
Frequency and wavelength are inversely related
What happened to intensity if the amplitude of a signal is halve? - ANSWERSQuarted/
Intensity is proportional to the amplitude squared, so if the amplitude is halved, the
resulting intensity is one fourth the original intensity
Duty factor - ANSWERSis the percentage of the time the sound is being transmitted
, A 3dB gain would indicated in intensity by: - ANSWERS2 times (A gain of 3dB results in
doubling of intensity (or power))
Ignoring the effects of attenuation, the intensity of ultrasound beam is usually greater at
the focal zone because of: - ANSWERSThe smaller beam diameter (Intensity equals
power divided by area. The area is smallest in the focal zone; therefore, the intensity is
highest)
Attenuation denotes: - ANSWERSis the weakening of the strength of the beam, typically
from absorption, reflection, or scattering
SATA - ANSWERSis the lowest of the intensities
Beam Uniformity Ratio - ANSWERSBUR= SP/SA
Continuous Wave Doppler has a duty factor of: - ANSWERS100%
SPL - ANSWERSThe spatial pulse length is defined as the product of the wavelength
and the number of cycles in a pulse (SPL= wavelength time the number of cycles in the
pulse)
SPTP - ANSWERShighest intensity
The unit for impedance is ________. - ANSWERSRayl
ALARA stands for - ANSWERSAs Low As Reasonably Achievable
Snell's law describes: - ANSWERSrefraction at an interface
Matching Layer - ANSWERSHas an impedance between skin and the active element so
more sound energy is transmitted between the crystal and skin
Quality Factor - ANSWERSoperating frequency/bandwidth
spatial resolution - ANSWERSis the ability to discern two closely reflectors as individual
reflectors
Infrasound - ANSWERSSound waves with a frequency less than 20 Hz
Pascual (Pa) - ANSWERSunit for pressure amplitude
W/cm2 - ANSWERSunit for intensity
Pulse Repetition Frequency - ANSWERSthe number of pulses per second
QUESTIONS WITH ACCURATE
ANSWERS
SPL - ANSWERSwavelength x # of cycles
With phased array transducers, the transmitted sound beam is steered by -
ANSWERSVarying the timing of pulses to the individual piezoelectric elements
What type of wave is sound? - ANSWERSmechanical and longitudinal
The Frequency ranges for Ultrasound are: - ANSWERS> 20,000 Hz (20kHz)
The speed of sound in soft tissue is: - ANSWERS1540 m/s
Linear sequence Array - ANSWERStransducer that fires the elements in groups
Unit for Wavelength - ANSWERSis millimeters
Enhancement is caused by - ANSWERSweakly attenuating structures (such as a cyst)
The wavelength in a material having a propagation speed of 1.5 mm/us employing a
transducer frequency of 5.0 MHz is: - ANSWERS0.3 mm Wavelength= c/f = 1.5mm/us ÷
5MHz = 0.3mm
An ultrasound transducer converts: - ANSWERSelectrical energy into mechanical
energy and vice versa
The order of attenuation, from the lowest attenuation to highest: - ANSWERSfat,
muscle, bone, air
Propagation Speed from the lowest to highest: - ANSWERSair, fat, muscle, bone
If the frequency doubled, what to wavelength? - ANSWERSDecrease by one half/
Frequency and wavelength are inversely related
What happened to intensity if the amplitude of a signal is halve? - ANSWERSQuarted/
Intensity is proportional to the amplitude squared, so if the amplitude is halved, the
resulting intensity is one fourth the original intensity
Duty factor - ANSWERSis the percentage of the time the sound is being transmitted
, A 3dB gain would indicated in intensity by: - ANSWERS2 times (A gain of 3dB results in
doubling of intensity (or power))
Ignoring the effects of attenuation, the intensity of ultrasound beam is usually greater at
the focal zone because of: - ANSWERSThe smaller beam diameter (Intensity equals
power divided by area. The area is smallest in the focal zone; therefore, the intensity is
highest)
Attenuation denotes: - ANSWERSis the weakening of the strength of the beam, typically
from absorption, reflection, or scattering
SATA - ANSWERSis the lowest of the intensities
Beam Uniformity Ratio - ANSWERSBUR= SP/SA
Continuous Wave Doppler has a duty factor of: - ANSWERS100%
SPL - ANSWERSThe spatial pulse length is defined as the product of the wavelength
and the number of cycles in a pulse (SPL= wavelength time the number of cycles in the
pulse)
SPTP - ANSWERShighest intensity
The unit for impedance is ________. - ANSWERSRayl
ALARA stands for - ANSWERSAs Low As Reasonably Achievable
Snell's law describes: - ANSWERSrefraction at an interface
Matching Layer - ANSWERSHas an impedance between skin and the active element so
more sound energy is transmitted between the crystal and skin
Quality Factor - ANSWERSoperating frequency/bandwidth
spatial resolution - ANSWERSis the ability to discern two closely reflectors as individual
reflectors
Infrasound - ANSWERSSound waves with a frequency less than 20 Hz
Pascual (Pa) - ANSWERSunit for pressure amplitude
W/cm2 - ANSWERSunit for intensity
Pulse Repetition Frequency - ANSWERSthe number of pulses per second
