Spi Exam Questions Verified Correct
Answers Current Update
what does the mechanical index indicate on an ultrasound system - Answer- ✔✔the
likelihood of cavitation during an ultrasound exam
mechanical index - Answer- ✔✔Calculated number related to the likely bioeffects
from cavitation
The maximum heating of tissue is related to - Answer- ✔✔the sound beams spatial
pulse temporal average (SPTA)
cavitation - Answer- ✔✔the action of an acoustic field within a fluid to generate
bubbles
2 types of cavitation that occur: - Answer- ✔✔stable cavitation: produces bubbles
that oscillate in size but do not rupture
transient cavitation: referred as collapse, has the potential to cause more
biological damage.
spta in an unfocused beam - Answer- ✔✔below 100mw/cm2
spta in a foucused beam - Answer- ✔✔1 w/cm2
The thermal index indicates - Answer- ✔✔Estimated temperature increase in tissue
Which intensity parameter is not applicable for continuous-wave ultrasound - Answer-
✔✔SPPA ans SAPA.
Pulse average intensities do not apply to CW
PW doppler has the highest - Answer- ✔✔SPTA value
hydrophone - Answer- ✔✔small transducer that measures the characteristics of a
sound beam
A hydrophone measures: - Answer- ✔✔the acoustic pressure at specific locations
within the sound beam
the hydrophone also measures - Answer- ✔✔period, PRP, PRF, PD, pressure
amplitude and duty factor
, acoustic streaming - Answer- ✔✔the steady, circular flow of cellular fluids induced
by ultrasound
propagation speed found in tissue - Answer- ✔✔FAT- 1460 m/s (LOWEST
PROPAGATION SPEED)
liver- 1555 m/s
blood-1560 m/s
muscle-1600 m/s
BONE- 4080 m/s (HIGHEST PROPAGATION SPEED)
Impedence is not affected by _________.
It is affected by: (3) - Answer- ✔✔FREQUENCY
1. STIFFNESS
2. DENSITY
3. PROPAGATION SPEED
what is the purpose of the gel coupling between the transducer and the skin - Answer-
✔✔To provide a medium for sound transmission, since ultrasound does not
propagate through air.
Any air between the transducer and skin would cause total reflection and poor
coupling
An example of specular reflector is - Answer- ✔✔pericardium
shadowing posterior to each lateral border of the cyst is - Answer- ✔✔Bending of the
sound beam due to different media propagation speeds
Interference - Answer- ✔✔the combination of two or more waves that results in a
single wave
Diffraction - Answer- ✔✔phenomenon associated with a pattern produced by a
sound beam after passing through a small aperture
diffraction is also known as - Answer- ✔✔spherical waves, diffraction patterns, or
huygen's wavelets
snell's law describes - Answer- ✔✔The angle of sound transmission at an interface
between media having different propagation speeds
sound propagates faster in materials with greater - Answer- ✔✔stiffness
Sound Attenuation is observed by - Answer- ✔✔reflection
scattering
conversion of sound to heat
absorption
Answers Current Update
what does the mechanical index indicate on an ultrasound system - Answer- ✔✔the
likelihood of cavitation during an ultrasound exam
mechanical index - Answer- ✔✔Calculated number related to the likely bioeffects
from cavitation
The maximum heating of tissue is related to - Answer- ✔✔the sound beams spatial
pulse temporal average (SPTA)
cavitation - Answer- ✔✔the action of an acoustic field within a fluid to generate
bubbles
2 types of cavitation that occur: - Answer- ✔✔stable cavitation: produces bubbles
that oscillate in size but do not rupture
transient cavitation: referred as collapse, has the potential to cause more
biological damage.
spta in an unfocused beam - Answer- ✔✔below 100mw/cm2
spta in a foucused beam - Answer- ✔✔1 w/cm2
The thermal index indicates - Answer- ✔✔Estimated temperature increase in tissue
Which intensity parameter is not applicable for continuous-wave ultrasound - Answer-
✔✔SPPA ans SAPA.
Pulse average intensities do not apply to CW
PW doppler has the highest - Answer- ✔✔SPTA value
hydrophone - Answer- ✔✔small transducer that measures the characteristics of a
sound beam
A hydrophone measures: - Answer- ✔✔the acoustic pressure at specific locations
within the sound beam
the hydrophone also measures - Answer- ✔✔period, PRP, PRF, PD, pressure
amplitude and duty factor
, acoustic streaming - Answer- ✔✔the steady, circular flow of cellular fluids induced
by ultrasound
propagation speed found in tissue - Answer- ✔✔FAT- 1460 m/s (LOWEST
PROPAGATION SPEED)
liver- 1555 m/s
blood-1560 m/s
muscle-1600 m/s
BONE- 4080 m/s (HIGHEST PROPAGATION SPEED)
Impedence is not affected by _________.
It is affected by: (3) - Answer- ✔✔FREQUENCY
1. STIFFNESS
2. DENSITY
3. PROPAGATION SPEED
what is the purpose of the gel coupling between the transducer and the skin - Answer-
✔✔To provide a medium for sound transmission, since ultrasound does not
propagate through air.
Any air between the transducer and skin would cause total reflection and poor
coupling
An example of specular reflector is - Answer- ✔✔pericardium
shadowing posterior to each lateral border of the cyst is - Answer- ✔✔Bending of the
sound beam due to different media propagation speeds
Interference - Answer- ✔✔the combination of two or more waves that results in a
single wave
Diffraction - Answer- ✔✔phenomenon associated with a pattern produced by a
sound beam after passing through a small aperture
diffraction is also known as - Answer- ✔✔spherical waves, diffraction patterns, or
huygen's wavelets
snell's law describes - Answer- ✔✔The angle of sound transmission at an interface
between media having different propagation speeds
sound propagates faster in materials with greater - Answer- ✔✔stiffness
Sound Attenuation is observed by - Answer- ✔✔reflection
scattering
conversion of sound to heat
absorption
