Ultrasound Physics 3&4
as an ultrasound wave travels through the body, its amplitude usually.
decreases
as sound travels in the body, what typically happens to the intensity of the wave
decreases
what happens to the pulse repetition period if the sonographer decreases the maximum imaging depth achieved in an ultrasound scan
decreases
The sonographer has the ability to alter the period of an ultrasound wave that is produced by a basic transducer.
false
with standard pulses, the frequency of the ultrasound change significantly as the wave propagates through the body
false
when the power in an acoustic beam is doubled and the cross-sectional area of the beam is halved, then the intensity of the beam is
four time larger
_________is the reciprocal of period
frequency
what term describes the number of cycles that an acoustic variable completes in a second
frequency
as a general rule, which of the following lists media in increasing order of propagation speeds
gas, liquid, solid
ultrasound is defined as a sound with a frequency of
greater than 0.02 Mhz
what happens to the intensity of an ultrasound beam when the beams cross sectional area remains unchanged while the amplitude of the wave triples
increases ninefold
what happens when the power in an ultrasound beam is unchanged, and at the same, the beam area doubles
is halved
which of the following units are appropriate to describe the period of an acoustic wave? More than one answer may be correct
minutes and microseconds
the pulse duration is expressed in the same units as the ______
period
what is the pulse duration equal to
period multiplied by the number of cycles in the pulse
the intensity of an ultrasound beam is defined as the ____in a beam _______by the ______of the beam.
power, divide, area
with standard ultrasound imaging, what happens to the period of a wave as it propagates?
remains the same
in diagnostic imaging what establishes the pulse repetition frequency
the source of the sound
what determines the pulse duration
the source of the wave
which of the following correctly describes pulse repetition period
the sum of the pulses "on" time and the listening "off" time
what determines period of an ultrasound wave.
the transducer
what determines the initial amplitude of an ultrasound wave
transducer
what establishes the frequency of an ultrasound wave
transducer
if the power of the beam is tripled while the cross sectional area of the beam remains the same the intensity
triples
if the period of two waves are the same, then the frequencies of the waves must also be the same
true
the pulse duration o fan ultrasound and transducer system does not change significantly as long as the system components remain unchanged
true
with standard diagnostic imaging instrumentation, the sonographer has the ability to vary the amplitude of a sound wave produced by the transducer
true
what are the units of intensity
watts/cm2
which of the following best describes the spatial pulse length
wavelength multiplied by the number of cycles in the pulse
Typically as an ultrasound wave travels through soft tissue the powernof the wave
decreases
which of the following terms best describes the relationship between frequency and wavelength for sound traveling in soft tissue
inverse
infra-sound is defined as a sound with a frequency of
less than 10 Mhz
two transducers send ultrasound pulses into soft tissue. one transducer emits sound with a 4 Mhz frequency, and the other produces sound at 6 Mhz frequency. Each pulses contains 4 cycles. Which has a greater spatial pulse length?
the 4 Mhz pulse
what is the wavelength of 10 Mhz sound in soft tissue
0.15mm
what is the wavelength of 2 Mhz sound in soft tissue
0.77 mm
the amplitude of an acoustic wave decreases from 27 pascals to 9 pascals. If the initial power in the wave was 27 watts, what is the waves power
3 watts
when a sonographer increases the maximum imaging depth during an exam, what happens
PRF decreases
Using a specific transducer, what happens to the spatial pulse length does not change as long as the components of the ultrasound system are the same
Remains the same
While imaging soft tissue, the spatial pulse length does not change as the components of the ultrasound system are the same
True
the wavelength of an ultrasonic wave is determined by
both A and B sound source, medium through which wave
