Exam 1 Review (Ch 1-5)

Term
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As imaging depth increases, PRF _ _______.
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Terms in this set (222)
As imaging depth increases, PRF _ _______.
decreases
T/F: Long pulses create more accurate images.
False
A sonographer increases the amplitude of a sound wave by a factor of 4. How has the power changed?
Increased by 16-fold
Calculate the intensity of a sound beam with a power of 1 W and area of 4 cm ^2.
4 cm^2
What is essentially equal to the power of a wave divided by the are over which the power is distributed?
Intensity
Pressure is typically expressed in _______.
Pascals
The speed of sound:
Depends on the elasticity and density of a medium.
What is the unit for intensity?
W/cm2
The prefix "centi" denotes:
hundredths
Which of the following intensities has the highest value?
SPTP
All of the following are true of stiffness except:Stiffness and propagation speed are INDIRECTLY related. *This is false*T/F: Sound waves can travel in a vacuum.FalseWhat is the wavelength of 5 MHz ultrasound in soft tissue?1.54/5= 0.308 or 0.3 mmWhat is the change in intensity if the power decreases by half?Intensity is halvedAn increase in pulse repetition frequency would lead to:An increase in duty factorSound is a ______- wave where particles move in the same direction that the wave propagates.longitudinalDetermine the speed of a sound beam that travels a total of 200 cm in 50 seconds.4 cm/sAll of the following relate to the strength of the sound wave except: Amplitude Wavelength Intensity PowerWavelengthWhich of the following is considered the speed of sound in soft tissue?1.54 mm/usAreas of high pressure and density are referred to as:CompressionsWhat does a duty factor of zero mean?The system is offIn clinical imaging a pulse typically contains ______ cycles.2-4Density and propagation speed are:inversely relatedThe prefix "micro" denotes:millionthIncreasing the frequency on a multifrequency transducer from 3.5 MHz to 5.0 MHz will:Decrease the wavelengthWhich intensity is most relevant with respect to bioeffects?SPTAWhat is defined as the beginning of one pulse to the beginning of the next pulse?Pulse repetition periodWhat is the complementary metric unit AND symbol for giga (G)?nano (n)Density is typical measured in:kg/cm^3If the frequency is unchanged but the propagation velocity changes, the wavelength:ChangesIf only the density of a medium is increased, then the:Propagation speed will decreaseAll of the following characteristics create pulses of short duration except:Many cycles in the pulseAs imaging depth increases, the pulse repetition frequency must:IncreaseHow are power and intensity related?DirectlyWhich of the following is an appropriate unit of measurement for propagation speed?Millimeters per microsecond (mm/us)What is the frequency of a sound wave with 16 cycles in 4 seconds?4 HzWhich of the following would be considered ultrasonic?12.5 kHzMicro denotes:MillionthWrite the formula for duty factor.(pulse duration/ PRP) x 100All of the following are true of wavelength except:It is equal to the period divided by the frequency.A sonographer increases the amplitude of a wave by a factor of 5. How has the power changed?25-fold4 MHz is ________ Hz.4,000,000Select the sequence of the following prefixes of metric system that appears in decreasing order:G, M, k, da, dThe wavelength of a 7MHz ultrasound beam in soft tissue is ________.0.22 mmIf the period is 0.5 microseconds, what is the frequency?2 MHzDuty factor can be calculated by:Dividing pulse duration by pulse repetition period.Which of the following is described as the distance over which one cycle occurs?WavelengthThe distance that a pulse occupies in space from the start to the end of a pulse is called:Spatial pulse lengthWrite the formula for spatial pulse length.# of cycles x wavelengthWhich of the following characteristics will create the slowest speed of sound?High density, low stiffnessYou are scanning a patient with suspected gallstones using a 3 MHz transducer. You do not detect a good shadowing distal to the suspected gallstone. What can you do to enhance visibility of the acoustic shadow distal to the gallstones?Increase the transducer frequencyIf the wavelength is 2 mm, the spatial pulse length for a three-cycle pulse is:6 mmSound is technically a:mechanical and longitudinal waveDetermine the wavelength produced by a 5.0 MHz transducer traveling in soft tissue.0.3 mmWhich of the following frequencies has the longest period?6 HzWhich of the following is defined as only the active time?pulse durationWhich is defined as the beginning of one pulse to the beginning of the next pulse, and therefore includes both the "on" and "off" time?Pulse repetition periodWhich of the following would have the highest propagation speed?BoneThe typical range of frequency for diagnostic ultrasound imaging is:2 MHz-15 MHzThe percentage of time that the ultrasound system is producing pulses of ultrasound describes the:Duty FactorWhat is the change in power if the amplitude triples?It increases nine times.What does bulk modulus refer to?StiffnessSpatial pulse length can be calculated by:Multiplying the number of cycles times the wavelengthIf the frequency is 1 MHz, what is the period?1 microsecondThe duty factor for continuous wave ultrasound is:100%T/F Propagation speed increases as frequency increases.FalseWhat are the effects of sound waves on tissue in the body called?BioeffectsT/F A wave with a frequency of 15,000 MHz is ultrasonic.TrueWhich of the following characteristics will create the fastest speed of sound?Low density, high stiffnessIf intensity remains the same while the power is doubled, what has happened to the beam area?DoubledHow many kilometers are in 3,000 meters?3Which of the following is an appropriate unit for area?square yardsWhat is the vertical axis of a graph called?Y-axisWhat is the name of the horizontal axis of a graph?x-axisHow are scores on the ultrasound board exams related to study time?DirectlyHow are calorie intake and weight related?DirectlyHow is weight related to a sonographer's time spent exercising?InverselyWhat is the reciprocal of 1000?1/1000 or 0.001What is the reciprocal of 5?1/5What is the reciprocal of 1/10?10A sack contains 6 pounds of flour. The contents of the bag are increased by a factor of 5. How much flour is in the bag?30 poundsA bouquet has 30 flowers. The size of the bouquet decreased by a factor of 3. How many flowers remain?10Which of the following is not a measure of area?cubic metersA sonographer measures the perimeter of an anatomical structure. Which of the following choices is a reasonable value for the measurement? A. 6 cm2 B. 5 cc C. 15 mm D. 18 dB15 mmWhat are the units associated with the circumference of a circle?mmThe volume of a cystic structure is estimated from sonographic data. Which of the following is an acceptable measurement of this volume?6 cm^3The speed of red blood cells traveling through a blood vessel is 750 cm/sec. You are asked to measure this speed in miles per hour. What information would be sufficient for you to complete your task?How many seconds per hour and the number of miles in a centimeter.How much bigger is one billion than one thousand?1,000,000 timesSelect the sequence that appears in increasing order.centi, deci, deca, hectoHow many nanoseconds are in 7 seconds?7,000,000,000 Nano means billionth.The letters below represent the abbreviations for the prefixes of the metric system. Select the sequence that appears in decreasing order. A. m, k, M, g, da B. g, m, k, d, u C. g, k, di, m, u, n D. M, k, da, d, cM, k, da, d, cMatch the following prefixes with their meanings.Mega - millions hecto- hundreds mili- thousandths kilo- thousands nano- billionths giga- billionsWhich term is the reciprocal of mega?microHow can the volume of an irregularly shaped object be measured most accurately? A. by visual inspection B. by its weight C. by immersing it in water D. by ultrasound scanningBy immersing it in waterWhat term is used to describe the effects of an ultrasound wave on living tissues?Biological effectsAs sound travels through a medium, what term describes the effects of the medium on the sound wave?Acoustic propagation propertiesWhich of the following is true of all waves?all carry energy from one site to anotherWhich of the following types of waves do not require a medium in order to propagate?heat, televisionWhich of the following describes the characteristics of a sound wave?Mechanical, longitudinalSound is best described as ________.A series of compressions and rarefactionsAll of the following are true about sound waves except ________.They are transverseWhat are the units of a pressure measurement of an acoustic wave?Pascals (Pa) Millimeter of mercury (mm Hg) Pounds/sq. inchSound can be characterized as:cyclical oscillations in certain variablesA force is applied to a surface. If the force is tripled and the surface area over which the force is applied is also tripled, what is the new pressure?UnchangedA longitudinal wave propagates from east to west at a speed of 2 miles per hour. What is the direction of motion of the particles within the wave.Alternatively from east to west and then from west to east.The direction of motion of a particle in a wave is perpendicular to the direction of propagation of the wave. What type of wave is this?TransverseA particle within a transverse wave is traveling vertically. What is the direction of the wave's propagation?HorizontalWaves that exist at the same location and time will combine. What is this called?InterferenceTwo waves arrive at the same location and interfere. The resultant sound wave is smaller than either of the two original waves. What is this called?Destructive interferenceA pair of waves are in phase. What occurs when these waves interfere?Constructive interferenceWhat is the range of periods commonly found in waves produced by ultrasound systems?0.06-0.5 microsecondsWith standard ultrasonic imaging, what happens to the period of a wave as it propagates?Remains the sameWhat determines the period of an ultrasound wave?The transducerWhich of the following units are appropriate to describe the period of an acoustic wave?minutes, microsecondsT/F: The sonographer has the ability to alter the period of and ultrasound wave that is produced by a basic transducer.FalseWhat term best describes the number of cycles that an acoustic variable compels in a second?FrequencyWhich of the following cannot be considered a unit of frequency?cyclesWhat is the range of frequencies emitted by transducers used in ultrasonic imaging2,000,000 - 15,000,000 HzWhat establishes the frequency of an ultrasound wave.The transducerT/F With standard ultrasound pulses, the frequency of the ultrasound changes significantly as the wave propagates through the body.FalseWhen a sonographer increases the maximum imaging depth during an exam, what happens to the frequency?Remains the sameUltrasound is defined as a sound with a frequency of ______.greater than 0.02 MHzInfrasound is defined as a sound with a frequency of ______.less than 20 HzT/F waves in the ultrasound range behave in the same general manner as sound waves that are audible.TrueWhat is characteristic of acoustic waves with frequencies exceeding 20,000 Hz when compared with waves having frequencies of less than 20,000 Hz.Humans can't hear themWhat is characteristic of acoustic waves with frequencies of less than 20 Hz when compared with waves having frequencies of more than 20 Hz?Humans can't hear themThe frequency of continuous acoustic wave is 5 MHz. The wave is then pulsed with a duty factor of 0.1. What is the new frequency? A. 0.5 B. 0.5 MHz C. 5 MHz D. 10 MHz5 MHzT/F The period of an ultrasound wave is related to the frequency and is the same regardless of whether the wave is pulsed or continuousTrueT/F: If the periods of two waves are the same, then the frequencies of the waves must also be the same.TrueCompare two sounds waves, A and B. The frequency of wave A is one-third that of wave B. How does the period of wave A compare with the period of wave B?A is three times as long as B____- is the reciprocal of period.frequencyWhat determines the initial amplitude of an ultrasound wave?The transducerT/F: With standard diagnostic imaging instrumentation, the sonographer has the ability to vary the amplitude of a sound wave produced by the transducer.TrueAs an ultrasound wave travels through the body, its amplitude usually:decreasesWhich of the following are acceptable units for the amplitude of an acoustic wave?cm, pascalsThe maximum value of the density of an acoustic wave is 60 lb/in2 while the minimum density is 20 lb/in2. What is the amplitude of the wave? A. 20 lb/in2 B. 40 lb/in2 C. 60 lb/in2 D. none of the above40 Ib/in^2 Subtract the minimum from the maximumThe power of an ultrasound wave can be reported with which of the following units?wattsTypically, as an ultrasound wave travels through soft tissue, the power of the wave:decreasesT/F: A sonographer can routinely chance the power of a wave emitted by a transducer used in diagnostic imaging?TrueMathematically, when a number is squared, the number is multiplied by:itselfThe final amplitude of an acoustic wave is reduced to one-half of its original value. the final power is ___ the original power. A. the same as B. one-half C. double D. none of the aboveNone of the aboveThe 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 wave's final power?3 wattsThe intensity of an ultrasound beam is defined as the ____ in a beam _____ by the ____ of the beam.power, divided, areaAs sound travels through in the body, what typically happens to the intensity of the wave?decreaseswhat are the units of intensity?watts/cm2T/F: With diagnostic ultrasonic imaging instruments, the operator can alter the intensity of an ultrasound beam produced by a transducer.TrueWhat determines the initial intensity of the ultrasound beam?The source of the sound waveWhat determines the intensity of an ultrasound beam after it has traveled through the body?The sound wave's source & the medium through which the sound travels.What are the units of the transmitted intensity of a sound wave?W/cm^2What happens when the power in an ultrasound beam is unchanged, and at the same time, the beam area doubles?Is halvedWhat happens to the acoustic beam's intensity when the power in the beam increased by 25% while the cross-sectional area of the beam remains the same?It increases by 25%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 times largerWhat happens to the intensity of an ultrasound beam when the beam's cross-sectional area remains unchanged while the amplitude of the wave triples?Increases nine-foldThe amplitude of an acoustic wave is increased. which of the following will most likely remain unchanged? (more than one answer may be correct)Frequency & PeriodA sonographer adjusts the output power of the wave emitted by the transducer. Which of the following also changes?IntensityThe wavelength of a cycle in an ultrasound wave can be reported with which units?Units of distance (feet, etc)The wavelength of an ultrasonic wave is determined by:The sound source & the medium through which the wave travels.What is the wavelength of 2 MHz sound in soft tissue?0.77 mmWhich of the following terms best describes the relationship between frequency and wavelength for sound traveling in soft tissue?inverseT/F: Lower frequency sound creates higher quality images with greater detail.FalseWhat is the wavelength of 10 MHz sound in soft tissue?0.15 mmPropagation speed can be correctly recorded with which of the following units?Miles per hour mm/msec km/sec inches per yearTwo sound pulses travel through the same medium. One waves frequency is 2 MHz and the other is 10 MHz. Which sound wave has a longer period? A. 10 MHz pulse B. 2 MHz pulse C. neither pulse D. cannot be determinedThe 2 MHz pulseTwo sound pulses travel through the same medium. One waves frequency is 2 MHz and the other is 10 MHz. Which pulse has a longer wavelength?The 2 MHz pulseTwo sound pulses travel through the same medium. One waves frequency is 2 MHz and the other is 10 MHz. Which pulse has the lower propagation speed?All the propagation speeds are the same because speed is determined by the medium.Two sound pulses travel through the same medium. One waves frequency is 2 MHz and the other is 10 MHz. Which pulse has the lowest power?The power of the wave is not related to the frequency. The power relates to the strength of the wave.T/F lower frequency sound creates higher quality images with greater detail.FalseT/F The frequency of a wave increases as it travels through a mass.FalseT/F The period of the sound wave increases as it travels through the mass.FalseT/F The wavelength increases while it travels through a mass.TrueT/F The power in the wave increases as it travels through a mass.FalseT/F: Shorter wavelength sound creates higher quality images with greater detail.TrueT/F: The wavelength of an acoustic wave is shorter when it is pulsed rather than continuous.FalseThe speed of sound traveling through bone is ____ soft tissue.higher thanCompared to soft tissue, the speed of an acoustic wave through lung tissue is _____.lower thanWhat is the best estimate for the speed of sound in tendon?1,754 m/sAs a general rule, which of the following lists media in increasing order of propagation speeds?gas, liquid, solidWhat is the speed of sound in air?330 m/sT/F Soft tissue is an imaginary construct that actually does not existTrueWhat is the propagation speed of a 5 MHz sound wave in soft tissue?1.54 mm/usIf sound travels at exactly 1,540 m/sec in a particular medium, then the medium ____. A. must be soft tissue B. may be soft tissue C. cannot be soft tissuemay be soft tissueIf sound doesnt travel at 1,540 m/sec in a medium, then the medium ___ A) must be soft tissue B) may be soft tissue C) cannot be soft tissueCannot be soft tissueThe propagation speeds of ultrasound in muscle, liver, kidney, and blood are _______.very similar to each otherThe speed at which a wave travels through a medium is determined by:The medium's properties onlyWhat two properties establish sound's propagation speed in a given medium?density & stiffnessThe characteristics of 4 media are described below, Which of the media has the slowest propagation speed?High density & high elasticity (the opposite of stiffness is elasticity)Compressibility describes a characteristic of a medium. Which two terms describe the same property as compressibility?Stiffness & elasticityWhen the elasticity of a medium is high, the ____ is high.compressibilityWhat are the units of pulse duration>units of time (sec, years, etc.)What determines pulse duration?the source of the waveT/F: The pulse duration of an ultrasound and transducer system does not change significantly as long as the system components remain unchanged.TrueThe pulse duration is expressed in the same units as the ______.periodT/F: A sonographer can adjust the duration of an acoustic pulse since it depends on the pulses propagation speed.FalseT/F: A sonographer can adjust the duration of an acoustic pulse since it depends on the maximum imaging depth.FalseT/F: The sonographer cannot change the duration of a sound pulse unless the transducers are switched.TrueThe pulse duration cannot be changed under any circumstances or by any action of the sonographer.False: The sonographer can change this if they use a different transducer or system.What is the pulse duration equal to?period multiplied by the number of cycles in the pulseWhat happens to the pulse duration when a sonographer decreases the maximum imaging depth in an ultrasound scan?Remains the sameThe spatial pulse length describes certain characteristics of an ultrasound pulse. What are its units?metersIn diagnostic imaging, what determines the spatial pulse length?The ultrasound system & the medium through which the pulse travels.Using a specific transducer, what happens to the spatial pulse length as the sonographer increases the maximum imaging depth?Remains the sameT/F While imaging soft tissue the spatial pulse length does not change as long as the components of the ultrasound system are the same.TrueOn what does the PRP depend?the source of the sound waveA sonographer adjusts the maximum imaging depth of an ultrasound system. Which of the following also changes?PRP & PRFWhich of the following correctly describes PRP?The sum of the pulse's "on" time and the listening "off" time.What happens to the pulse repetition period if the sonographer decreases the maximum imaging depth achieved in an ultrasound scan.DecreasesWhat are the units of PRF?1/secondsThe PRF of the ultrasound produced by a transfer typical of diagnostic imaging systems ________.can be changed by the sonographerIn diagnostic imaging, what establishes the PRF?source of soundWhen a sonographer increases the maximum imaging depth during an exam, what happens to the PRF?PRF decreasesT/F: the PRF and the frequency are unrelatedTrueWhat is a typical values for the duty factor of pulsed sound waves used in diagnostic imaging?0.001What is the value of the duty cycle for continuous wave ultrasound? A 100 B 1% C 1000% D Non of the aboveNon of the aboveIn the case of pulsed ultrasound, what is the maximum value of the duty factor?less than 100%While using a particular imaging system, what happens to the duty factor when the depth of view increases? A. increases B. decreases C. unchangedDecreasesT/F: The sonographer alters the duty cycle when adjusting the maximum imaging depth of a scan.TrueT/F The duty factor is a characteristic of an ultrasound and transducer system and does not change as long as the system components remain unchanged.FalseWhile using the same ultrasound machine and transducer, which of the following can a sonographer alter?PRP PRF Duty Factor (cycle)Which of the following terms does not belong with the others? A. Increased depth of view B. Increased duty factor C. Increased PRP D. Decreased PRFIncreased duty factorWhich of the following terms does not belong with the others? A. Increased depth of view B. Decreased duty factor C. Increased PRP D. Decreased spatial pulse lengthSpatial pulse lengthWhat is the importance of scribing sound beam intensities in a variety of ways with regard to space & time?It's important when studying bioeffectsWhich intensity is most closely correlated to tissue heating?SPTA