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90 Cards in this Set
- Front
- Back
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Ultrasound:
a) is a transverse wave b) is a mechanical wave c) is a longitudinal wave d) have particles that move up and down. |
B & C
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Ultrasound can travel through a vacuum.
True/False |
False
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Ultrasound is created by:
a) a transducer b) the vibration of a moving object c) the medium d) pressure |
B
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As sound propagates there are variations in quantities called _______ _________.
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Acoustic variables
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Which one of these is not an acoustic variable?
a) pressure b) partical motion (distance) c) parameters d) density e) temperature |
C
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Longitudinal wave particles move perpendicular to the direction of the wave.
True/False |
False. They move in the same direction.
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Transverse wave particles move in the same direction to the direction of the wave.
True/False |
False. They move perpendicular to the direction of the wave.
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All of the following are true of sound waves EXCEPT:
a) they are acoustic b) they are pressure waves c) they are transverse d) they move energy |
C
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Which of the following best describes sound waves?
a) a series of compressions and rarefactions b) waves that are heard by man c) movement of molecules and energy to one location to another. d) waves that are used to make images of anatomy. |
A
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Which of the following best describes sound waves?
a) transverse, pressure waves b) transverse, longitudinal waves c) longitudinal, out-of-phase waves d) longitudinal, pressure waves |
D
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Two waves are traveling in a medium and arrive at a location at the same time. What event takes place?
a) constructive interference b) destructive interference c) interference d) reflection |
C
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Which types of waves will exhibit both constructive and destructive interference?
a) waves of different amplitude b) a pair of longitudinal waves c) waves of different frequency d) out of phase waves. |
C
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Sound waves travel through areas of low density and high density. Areas of low density is referred to as ______________
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Rarefactions
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Sound waves travel through areas of low density and high density. Areas of high density is referred to as ______________
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Compressions
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Match the following frequency with it's proper sound wave:
1) Audible Sound 2) Infrasound 3) Ultrasound 4) Diagnostic Imaging a) >20 Hz b) >20,000 Hz (20 kHz) c) 20- 20,0000 Hz d) 2-12 MHz (1-15 MHz) |
1) c... 20-20,000 Hz
2) a....<20 Hz 3) b....>20,000 Hz (20 kHz) 4) d....2-12 MHz (1-15 MHz) |
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The time to complete1 cycle (the time from the start of a cycle to the start of the next cycle.
a) period b) frequency c) wavelength d) amplitude |
A
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Units for period:
a) mm, m, cm b) s, ms, us c) Hz, KHz, MHz |
B. Units of time.
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What are the typical values for period?
a) 0.2-0.7 s b) 2.0- 3.5 us c) 0.1-0.5 us d) 0.05- 0.5 ms |
C
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Period is determined by the sound source. It cannot be changed by the sonographer.
True/False |
True
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The number of cycles of an acoustic variable (pressure, particle motion (distance), density, and temperature) that occur in one second.
a) period b) frequency c) PRP c) PRF |
B
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Unit of measure for frequency:
a) MHz b) Hz c) kHz |
B
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Frequency is determined by the:
a) medium only b) medium & sound source c) sound source only |
C
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Frequency cannot be changed by the sonographer as long as the same transducer is being used.
True/False |
True
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In clinical imaging, frequency ranges are:
a) 2.5-10 MHz b) 3- 16 MHz c) 2.3 - 14 MHz d) 2-12 MHz |
D
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Frequency affects:
a) attenuation & lateral resolution b) penetration & axial resolution c) propagation speed & period |
B
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What is the relationship between period and frequency?
a) they are inversely related b) they are reciprocals c) they are directly proportional d) they are unrelated |
B.....this means they are opposites. When one increases, the other decreases.
P x f = 1 P = 1/f f = 1/P |
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The distance that one complete cycle occupies...the LENGTH of the cycle.
a) period b) frequency c) wavelength d) amplitude |
C
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Wavelength is determined by:
a) Sound source b) sonographer c) medium d) propagation speed |
A & C
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In clinical imaging, wavelength ranges from:
a) 0.25 - 0.6 mm b) 0.25 - 0.6 us c) 0.15 - 0.8 mm d) 0.15 - 0.8 s |
C
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Wavelength can be changed by the sonographer while using the same transducer.
True/False |
False
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How is frequency related to wavelength?
a) inversely b) unrelated c) directly proportional d) they are reciprocals |
A
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High frequency transducers have a long wavelength.
True/False |
False. f and wavelength are inversely related so is f is high wavelength is short.
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Lower f transducers have a longer wavelength.
True/False |
True. f and wavelength are INVERSELY related, so if f is low wavelength is long.
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Wavelength is the only parameter that is determined by both the sound source and the medium.
True/False |
True
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The speed at which sound travels through a medium or the distance that a sound wave travels through a medium in 1 second.
a) Pulse Repetition Period b) wavelength c) propagation speed d) amplitude |
C
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Propagation speed is determined by:
a) the sound source only b) the medium only c) the sound source and the medium d) time |
B
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propagation speed (c) units of measure:
a) s, ms, us b) cycles/second c) m/s, mm/us (distance/time) d) all of the above |
C
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Propagation speed in soft tissue:
a) 1540 m/s, 1.54 mm/us, 1.54 km/s b) 1540 mm/us, 1.54 m/s, 1.54 km/s c) 1540 km/s, 1.54 m/s, 1.54 mm/us |
A..This is approximately 1 mile per second.
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_______ & _______ determines the propagation speed of the medium.
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Stiffness and Density
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If stiffness increases propagation speed decreases?
True/False |
False. Think about bone. If stiffness increases, c increases.
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If density increases with no change in the stiffness, then c will decrease.
True/False |
True.
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Wave Equation
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lambda=c/f
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What is NOT a property of ultrasound waves?
a) Amplitude b) Distance c) Power d) Intensity |
B
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Medium 1 has a density of 9 and a stiffness of 6.
Medium 2 has a density of 8 and a stiffness of 6. In which medium will sound travel slower? |
medium 1....since both media have the same stiffness, the medium with the greater density has the lower propagation speed.
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Relates to the strength and magnitude of a sound wave.
a) amplitude b) power c) intensity d) pressure |
A
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Amplitude is the difference between the ____ value and the ____ value of an acoustic variable.
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average value & maximum value
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Amplitude can have units of any of the acoustic variables. Match the acoustic variables with it's unit of measure.
a) pressure b) density c) particle motion d) temperature 1) cm, inches, any distance 2) pascals 3) degrees 4) g/cm^3 |
a) pressure - 2) pascals
b) density - 4) g/cm^3 c) particle motion - 1) any distance d) temperature - 3) degrees |
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In clinical imaging, pressure amplitude ranges from 1 million pascals (1 MPa) to 3 million pascals (3 MPa).
True/False |
True
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INITIALLY, the amplitude is determined only by the:
a) medium b) sound source c) medium and sound source |
B
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Amplitude increases/decreases as sound propagates through the body.
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decreases
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The rate at which the amplitude decreases as sound propagates depends on the characteristics of:
a) the medium only b) the sound source only c) both the sound wave and the medium d) the medium and the sound source. |
C
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Can the sonographer alter the initial amplitude?
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Yes
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With CW, the positive and negative amplitudes are:
a) equal b) different c) inversely related d) proportional |
A
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With PW, the positive and negative amplitudes are often:
a) equal b) different c) inversely related d) proportional |
B
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What is the difference between amplitude and peak-to-peak amplitude?
a) amplitude is measured from the baseline of the maximum to the baseline of the minimum. b) the difference between maximum and minimum values of an acoustic variable. |
A
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What MUST occur within a wave for it to move?
a) power b) intensity c) pressure d) energy |
C
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Waves will go through areas of compression and rarefactions, which indicate areas of high and low pressure.
True/False |
True
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Relates to the strength of a sound wave:
a) pressure b) intensity c) amplitude d) power |
D
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Rate at which work is performed or energy is transferred from the entire sound beam.
a) pressure b) intensity c) amplitude d) power |
D
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Power can be controlled by the sonographer.
True/False |
True
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Power is determined initially by the
a) sound source b) medium c) sound source and the medium |
A
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Power decreases as sound propagates through the body.
True/False |
True
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The rate at which sound propagates depends on the characteristics of what?
a) the medium and the wave b) the density of the medium c) the sound source |
A
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How are amplitude and power related?
a) they are inversely related b) they are proportional c) they are unrelated |
B
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Power is proportional to amplitude squared.
True/False |
True
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If amplitude is tripled, what happens to power?
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it is tripled
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If amplitude is halved, what happens to power?
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it is halved.
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Related to the strength and concentration of energy in the sound beam.
a) power b) pressure c) intensity d) temperature |
C
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Intensity equation
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intensity (W/cm^2) = power (w)/ area^2
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Can intensity be controlled by the sonographer?
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yes
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Clinical imaging ranges for intensity:
a) 0.03-400 W/cm^2 b) 0.01-300 W/cm^2 c) 2.4-250 W/cm^2 d) 0.023-200 W/cm^2 |
B
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How is intensity related to both power and amplitude?
a) inversely b) directly c) unrelated |
B
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When power or amplitude of a beam increases, what happens to intensity?
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It is increased as well
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How is intensity related to power?
a) inversely b) proportional c) unrelated |
proportional
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How is intensity related to amplitude?
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Intensity=amplitude^2
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When discussing relationships between amplitude, power, and intensity, the word __________ ALWAYS follows the word amplitude.
a) cubed b) squared c) range |
B
Power is related to amplitude squared. Intensity is related to amplitude squared. Power in related to the intensity. |
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A unit used to express a relative difference between 2 acoustic signals.
a) Hz b) MHz c) dB |
C
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What is the wavelength of 3Mhz sound in soft tissue?
a) 0.51 m b) 0.51 km c) 0.51 mm d) 0.51 um |
C
In soft tissue, wavelength is 1.54mm divided by the f in MHz. Thus 3 MHz sound will have a wavelength of 0.51 mm. |
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What is the wavelength of a wave with an unknown f traveling in soft tissue?
a) 0.51 us b) 0.51 m/s c) 0.51 pascals d) 0.51 watts e) 0.51 mm |
E is the only answer with units of distance. Therefore, it is the best answer. Choice A has units of time, b has units of speed, C has units of pressure, and D has units of power.
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Which of the following is an acoustic variable? (Could be more than one)
a) frequency b) density c) particle motion d) temperature e) period f) pressure |
B, C, D & F
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The effects of tissue on sound waves are called _______ ______ ________.
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Acoustic propagation properties
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The effects of a medium on an u/s wave are called ________ ______ ____.
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Acoustic propagation properties.
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How are the following parameters related - directly, inversely, or unrelated?
f & period amplitude and power amplitude and intensity wavelength and intensity wavelength and f c & density elasticity and c c & compressibility stiffness & c f & c f & intensity power & f |
f & period......inversely
amplitude and power......directly amplitude and intensity....directly power and intensity....directly wavelength and intensity...unrelated wavelength and f....inversely c & density....inversely elasticity and c.....inversely c & compressibility....inversely stiffness & c.....directly f & c....unrelated f & intensity.....unrelated power & f....unrelated |
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Another word for stiffness
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bulk modulus
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What is usually the dominant factor that determines c?
a) the medium b)stiffness c) density d) the sound source |
B
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Harder media have a higher c.
True/False |
True
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List these media in order of their propagation speeds from lowest to highest:
solids, gases, liquids |
gases
liquids solids |
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What happens when propagating sound energy strikes a boundary between 2 media and some returns to the transducer?
a) reflection b) refraction c) scattering d) absorption |
A
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The acoustic resistance to sound traveling through a medium.
a) reflection b) refraction c) acoustic impedance d) scattering e) absorption |
C
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Acoustic impedance equation
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Z= density (p) (kg/m^3) x c (m/s)
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