Sonography Physics Midterm Review
Assume that the frequency of sound with the greatest power emitted by a transducer is 5 MHz. However, the pulse contains acoustic energy with frequencies as low as 3.5 MHz and as high as 6.5 MHz. What is the bandwidth of the transducer?
3.0 MHz
A pusled -wave transducer has a resonant frequency of 5 mHz, the lowest frequency in the pulse is 2 mHz and the highest is 8 mHz. What is the bandwidth?
6 MHz
You are asked to fabricate a pulsed ultrasound transducer with the lowest possible frequency. Which piezoelectric crystal would you select?
8 mm thick, 2 cm diameter, 2.0 mm/usec prop speed
What is the wavelength of a wave with an unknown frequency traveling in soft tissue?
0.51 mm
In soft tissue, sound travels to a reflector and back to the transducer in 39 usec (39 microsecond or 39 millionth of a sec) What is the total distance that the pulse traveled? A. 2 cm B. 6 cm C. 3 cm D. cannot be determined
B. 6 cm
Which of the following probes creates a beam with least divergence? A. 4 mm diameter, 4 MHz B. 6 mm diameter, 8 MHz C. 6 mm diameter, 2 MHz D. 5 mm diameter, 8 MHz
B. 6 mm diameter, 8 MHz
Which of the following probes creates a beam with the deepest focus? A. 4 mm diameter, 4 MHz B. 6 mm diameter, 8 MHz C. 6 mm diameter, 2 MHz D. 5 mm diameter, 8 MHz
B. 6 mm diameter, 8 Mhz
How many nano seconds are in 7 seconds? A. 7,00,000 B. 7,000,000,000 C. 7 million D. 0.00000007
B. 7,000,000,000
A sound wave is created by a transducer, reflects off an object, and returns to the transducer. The imaging depth is 10 cm in soft tissue. What is the maximum PRF? A. 7,700 B. 7.7 kHz C. 3,500 Pa D. 7.700 us
B. 7.7 kHz
As a pulse passes through soft tissue, a certain amount of acoustic energy remains in the tissue as heat. What is this constituent of attenuation called? A. scattering B. absorption C. refraction D. rarefaction
B. absorption
As sound travels through a medium, what term describes the effects of the medium on the sound wave? A. toxic effects B. acoustic propagation properties C. bioeffects D. transmission properties
B. acoustic propagation properties
Which of the following locations is the shallowest? A. beginning of the far zone B. beginning of the focal zone C. focal depth D. beginning of the Fraunhofer zone
B. beginning of the focal zone
What happens to the pulse repetition period if the sonographer decreases the maximum imaging depth achieved in an ultrasound scan?
B. decreases
While using a particular imaging system, what happens to the duty factor when the depth of view increases?
B. decreases
Which two attributes help establish the acoustic impedance of a medium? A. density and temperature B. density and stiffness C. stiffness and elastance D. elasticity and compressibility
B. density and stiffness
If the intensity remains the same while the power is doubled, what happened to the beam area? A. quadrupled B. doubled C. halved D. unchanged
B. doubled
What term describes the number of cycles that an acoustic variable completes in a second
B. frequency
Which type of transducer has more backing material ? A. therapeutic B. imaging
B. imaging
Which of the following terms does NOT belong with others? A. increased depth of view B. increased duty factor C. increased pulse repetition period D. decreased pulse repetition frequency
B. increased duty factor
What happens when the power in an ultrasound beam is unchanged, and at the same time, the beam area doubles? A. doubles B. is halved C. is quartered D. remains the same
B. is halved
The imaging depth during an ultrasound exam is 10 cm. The sonographer adjusts the imaging depth to 5 cm. What happens to PRP? A. it is unchanged B. it is halved C. it is doubled D. it is 20 times longer
B. it is halved
The maximum imaging depth during an ultrasound exam is 10 cm. The sonographer adjusts the imaging depth to 20 cm. What happens to PRF? A. it is unchanged B. it is halved C. it is doubled D. it is 20 times longer
B. it is halved
An acoustic wave is in medium A and traveling towards medium B. The sound beam's angle of transmission into medium B with relation to the boundary is 79 degrees sound's propagation speed is 1,547 m/sec in medium A and 1,745 m/sec in medium B. If reflection and transmission both occur at the boundary, what can be said of the reflection angle?
B. it is less than 79 degrees
What is the importance of describing sound intensities in a variety of ways with regard to space and time?
B. it's important when studying bioeffects
Infrasound is defined as a sound with a frequency of _______.
B. less than 2 Hz
Which of the following characteristics will create the the fastest speed of sound? A. high density, high stiffness B. low density, high stiffness C. high density, low stiffness D. low density, low stiffness
B. low density, high stiffness
A sound pulse travels in medium 1 and strikes an interface with another tissue, medium 2, at 30 degrees. The angle of transmission is 10 degrees. In which medium does the sound travel slowest? A. medium 1 B. medium 2 C. cannot be determined
B. medium 2
To calculate the acoustic impedance of a medium, one should ____ the _____ by the ______. A. divide, propagation speed, density B. multiply, density, propagation speed C. divide, density, propagation speed
B. multiply, density, propagation speed
What is the decibel notation for an acoustic signal that si attenuated? A. positive B. negative C. equal to zero
B. negative
Which of the following terms does NOT belong to the others? A. orthogonal B. oblique C. normal D. perpendicular
B. oblique
Variations in all of the following identify specific waves as acoustic waves EXCEPT. A. pressure B. parameters C. density D. acoustic variables
B. parameters
What event does Snell's Law govern? A. transmission B. refraction C. impedance
B. refraction
Which of the following terms does NOT belong with the others? A. low duty factor B. shallow imaging C. low PRF D. long pulse repetition period
B. shallow imaging
Compared to soft tissue, the speed of an acoustic wave through lung tissue is __________.
B. slower
Two sound pulses travel through the same medium. One wave's frequency is 2 MHz and the other is 10 MHz. Answer the following 5 questions (that is 12 to 16). Which pulse has a longer wavelength?
B. the 2 MHz pulse
Two sound pulses travel through the same medium. One wave's frequency is 2 MHz and the other is 10 MHz. Answer the following 5 questions (that is 12 to 16). Which sound wave has a longer period?
B. the 2 MHz pulse
Two transducers send ultrasound pulses into soft tissue. One transducer emits sound with a 4 MHz frequency, and the other produces sound at a 6 MHz frequency. Each pulse contains 4 cycles. Which has a greater spatial pulse length?
B. the 4 MHz pulse
The speed at which a wave travels through a medium is determined by
B. the medium's property only
which of the frequency is NOT amongst the spectrum of electromagnetic waves? A. x-ray B. ultrasound C. ultraviolet D. infrared E. visible light
B. ultrasound
A sound wave strikes a boundary with normal incidence. The impedances of the two media are identical. What percentage of the sound is refracted? A. 100% B. 75% C. 0% D. 25% E. 90%
C. 0%
What is the reciprocal of 1,000? A. one-hundredth B. 1000 C. 0.001 D. one-millionth
C. 0.001
A top is spinning on a table. What is the period of the spinning top?
C. 0.05 seconds
If the power in a beam is 1 watt and the area is 5 cm^2, what is the beam's intensity?
C. 0.2 W/cm^2
The impedance of a transducer active element is 1,900,000 Rayls, and the impedance of the skin is 1,400,000 Rayls. What is acceptable impedance for the matching layer? A. 1,200,000 Rayls B. 1,400,000 Rayls C. 1,726,000 Rayls
C. 1,726,000 Rayls
The propagation speed of continuous wave ultrasound is 1.8 kilometers per second. The wave is then pulsed with a duty factor of 50% . What is the new propagation speed? A. 0.5 km/sec B. 0.9 km/sec C. 1.8 km/sec D. 3.6 km/sec E. cannot be determined
C. 1.8 km/sec
A bouquet has 30 flowers. The size of the bouquet is decreased by a factor of 3 how many flowers remain? A. 27 B. 0 C. 10 D. 15
C. 10
The power in a wave is increased to ten times its original value. How many decibels describe the change?
C. 10
A sound wave is created by a transducer, reflects off an object, and returns to the transducer. The maximum imaging depth is 7.7 cm. What is the PRF? A. 7,700 kHz B. 5,000 kHz C. 10,000 Khz D. 100 us
C. 10,000 kHz
A sonographer measures the perimeter of an anatomical structure. Which of the following choices is a reasonable value for the measurement? A. 6 cm^2 B. 5 cc C. 15 mm D. 18 dB
C. 15 mm
Which of these four pulses with PRFs is listed below has the shortest pulse repetition period? A. 12 kHz B. 6,000 Hz C. 20 kHz D. 1 kHz
C. 20 kHz
A sound beam travels 9 cm in soft tissue. The attenuation coefficient is 34 dB/cm. What is the total attenuation that the sound beam experienced? A. 9 dB B. 3 dB C. 27 dB D. 18 dB
C. 27 dB
In soft tissue, sound travels to a reflector and back to the transducer in 39 usec. How deep is the reflector? A. 2 cm B. 6 cm C. 3 cm D. cannot be determined
C. 3 cm
A sound beam with an intensity of 45 w/cm^2 strikes a boundary and 70% of the wave's intensity is reflected. How much is transmitted? A. 45 w/cm^2 B. 25 w/cm^2 C. 30% D. 100%
C. 30%
Which of the following probes creates a beam with the most divergence? A. 4 mm diameter, 4 MHz B. 6 mm diameter, 8 MHz C. 4 mm diameter, 2 MHz D. 5 mm diameter, 8 MHz
C. 4 mm diameter, 2 MHz
A sound beam travels a total of 10 cm in 2 seconds. What is the speed of the sound? A. 10 cm/sec B. 2 cm/sec C. 5 cm/sec D. 0.2 cm/sec
C. 5 cm/sec
Which of the following probes creates a beam with shallowest focus? A. 4 mm diameter, 4 MHz B. 6 mm diameter, 8 MHz C. 6 mm diameter, 2 MHz D. 5 mm diameter, 8 MHz
C. 6 mm diameter, 2 MHz
Compare two sound waves, A and B the frequency of wave A is one-third that of B. How does the period of wave A compare to with the period of wave B?
C. A is three times as long as B
The wavelength of an ultrasonic wave is determined by: A. the sound source B. the medium through which the wave travels C. Both A & B D. neither A nor B
C. Both A & B
What conditions are necessary for refraction to occur at a boundary between two media?
C. Dissimilar propagation speeds and oblique incidence at the boundary
What units are used to report the pressure of a sound beam? A. pounds B. centimeters C. Pascals D. kg/cm
C. Pascals
Which statement is correct for intensities arranged from lowest to highest A. SPTP--SPPA--SPTA--SATA B. SPPA--SPTP--SATA--SPTA C. SATA--SPTA--SPPA--SPTP D. SPTA--SPPA--SATA--SPTP
C. SATA--SPTA--SPPA--SPTP
Which intensity is most closely correlated to tissue heating? A. SPTP B. SATP C. SPTA D. SATA
C. SPTA
Which of the following best describes the spatial pulse length? A. frequency multiplied by wavelength B. pulse repetition frequency multiplied by wavelength C. wavelength multiplied by the number of cycles in the pulse D. duty factor multiplied by the wavelength
C. Wavelength multiplied by the number of cycles in the pulse
What is decibel? A. the absolute value of a number B. a range of values C. a relationship between two numbers D. none of the above
C. a relationship between two numbers
As sound propagates through a medium, the total power in the wave decreases. What is the entire process called? A. absorption B. scattering C. attenuation D. reflection
C. attenuation
How can the volume of an irregularly shaped object be measured most accurate? A. by visual inspection B. by its weight C. by immersing in water D. by ultrasound scanning
C. by immersing in water
A sound pulse travels in medium 1 and strikes an interface with another tissue, medium 2, at 30 degrees. The angle of transmission is 10 degrees. In which medium is impedance higher? A. medium 1 B. medium 2 C. cannot be determined
C. cannot be determined
If sound doesn't travel at 1,540 m/s in a medium, then the medium ________.
C. cannot be soft tissue
Select the sequence that appears in increasing order. A. mega, kilo, hecto, milli, giga B. nano, milli, micro, deci, deca, mega C. centi, deci, deca, hecto D. milli, hecto, centi, deci, nano, giga
C. centi, deci, deca, hecto
Which of the following is NOT a measure of area? A. square cm B. meter squared C. cubic meters D. feet x feet
C. cubic meters
Which of the following terms does not belong? A. focus B. end of the near zone C. end of the Fraunhofer zone D. middle of the focal zone
C. end of the Fraunhofer zone
What do waves transfer from one location to another? A. matter B. molecules C. energy D. water
C. energy
Which of the following is NOT one of the physical processes that contribute to attenuation of ultrasound waves passing through soft tissue? A. reflection B. redirection of sound in many directions C. focusing D. conversion of acoustic energy to heat
C. focusing
To which of the following is Rayleigh scattering related?
C. frequency^4
The 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? A. how many seconds in a minute and how many blood cells in a vessel B. the number of miles in a meter C. how many seconds per hour and the number of miles in a centimeter D. the direction of red blood cells and the Doppler shift frequency
C. how many seconds per hour and the number of miles in a centimeter
If the _______ two media are different and sound strikes a border between the media at 90 degrees incidence, then reflection will occur A. conductance B. densities C. impedances D. propagation speed E. none of the above
C. impedances
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. interference
The maximum imaging depth (depth of view) during an ultrasound exam is 10 cm. The sonographer adjusts the imaging depth to 20 cm. What happens to pulse repetition period? A. it is unchanged B. it is halved C. it is doubled D. it is 20 times longer
C. it is doubled
An acoustic wave is traveling through soft tissue. Its intensity undergoes six decibels of attenuation. How does the final intensity of the wave relate to the intensity if the wave when it started its journey?
C. it is now one-fourth as large
In the case of pulsed ultrasound, what is the maximum value of the duty factor? A. 100% B. 1 C. less than 100% D. none of the above
C. less than 100%
Acoustic impedance is a property of the ______ and has the units of _____. A. source and medium, Imps B. medium, dB C. medium, Rayls D. medium, Ohms
C. medium, Rayls
The spatial pulse length describes certain characteristics of an ultrasound pulse. What are its units? A. time B. hertz C. meters D. none, it is unitless
C. meters
What is the region from the transducer to the smallest cross sectional area of a sound beam called? A. focus B. half-value thickness C. near zone D. Fraunhofer zone
C. near zone
Two sound waves with frequencies of 5 and 3 MHz travel to a depth of 8 cm in a medium and then reflect back to the surface of the body. Which acoustic wave arrives first at the surface of the body?
C. neither
Which pulse has a lower propagation of speed?
C. neither pulse
Which term does NOT belong in the group below? A. orthogonal B. at right angle C. oblique D. 90 degrees E. normal F. perpendicular
C. oblique
If all other factors remain unchanged, what happens to the duty factor when the sonographer uses a new transducer with long pulse duration?
C. remains the same
Using a specific transducer, what happens to the spatial pulse length as the sonographer increases the maximum imaging depth?
C. remains the same
What happens to the pulse duration when a sonographer decreases the maximum imaging depth in an ultrasound scan? A. increases B. decreases C. remains the same D. cannot be determined
C. remains the same
With standard ultrasonic imaging , what happens to the period of a wave as it propagates?
C. remains the same
When a sonographer increases the maximum imaging depth during an exam, what happens to the frequency?
C. remains unchanged
Which of the following probes will create a beam with the shallowest focus? A. small diameter, high frequency B. large diameter, high frequency C. small diameter, low frequency D. large diameter, low frequency
C. small diameter, low frequency
Which of the following is true of diffuse reflections? A. they are created by smooth boundaries B. they are created by large reflectors C. sound reflects in many directions D. they do not appear in soft tissue
C. sound reflects in many directions
An acoustic pulse reflects from a very smooth boundary where the irregularities on the surface of the boundary are much smaller than the pulse's wavelength what type of reflection is most likely to occur under these circumstances? A. partial B. rayleigh C. specular D. total
C. specular
Two ultrasound systems are identical except for the pulse repetition period (PRP) of the emitted pulse. Which system will have deeper focus? A. the system with low PRP B. the system with higher PRP C. their foci will be at the same depth
C. their foci will be at the same depth
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. they are transverse
Which of the following crystals will produce sound with the lowest frequency? A. thin and with low speed B. thin and with high speed C. thick and with low speed D. thick and with high speed
C. thick and with low speed
What are the units of pulse duration?
C. units of time (sec, year, etc)
Which type 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. waves of different frequency
What is the vertical axis of a graph called? A. z-axis B. x-axis C. y-axis D. time axis
C. y-axis
A sound wave is created by a transducer, reflects off an object, and returns to the transducer. The depth of the reflector is 10 cm in soft tissue. What is the go return time?
D. 130 us
What is the range of frequencies emitted by transducers used in ultrasonic imaging?
D. 2,000,000 to 15,000,0000 Hz
A 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? A. 6 pounds B. 11 pounds C. 60 pounds D. 30 pounds
D. 30 pounds
A sound wave is created by a transducer, reflects off an object, and returns to the transducer the go-return time is 26 us. What is the total distance that the pulse traveled? A. 1 cm B. 2 cm C. 3 cm D. 4 cm
D. 4 cm
The volume of a cystic structure is estimated from sonographic data. Which of the following is an acceptable measurement of this volume? A. 6 B. 6 cm C. 6 cm^2 D. 6 cm^3
D. 6 cm^3
Which of the following explains why a sound beam created by a disc shape crystal is hourglass shaped? A. Bernoulli's principle B. Sheffield law C. Ohm's law D. Huygens principle
D. Huygens principle
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, c
D. M, k, da, d, c
What is the value of the duty cycle for continuous wave ultrasound? A. 100 B. 1% C. 1000% D. none of the above
D. None of the above
Which of the following is considered a rayleigh scattering? A. bone B. liver C. muscle D. blood cell
D. blood cell
Which pulse has a longer spatial pulse length? A. the 10 MHz pulse B. the 2 MHz pulse C. neither pulse D. cannot be determined
D. cannot be determined
Which pulse has the lowest power?
D. cannot be determined
How are caloric intake and weight related? A. inversely B. partially C. reciprocally D. directly
D. directly
One reflector is 5 times deeper than another. The time of flight of sound to the deeper structure is ______ the time of flight of the shallower reflector. A. one fifth as much B. equal to C. less than D. five times more than
D. five times more than
When the power is an acoustic beam is doubled and the cross sectional area of the beam is halved, then the intensity of the beam is:
D. four time larger
As a general rule, which of the following lists media in increasing order of propagation speed?
D. gas, liquid, solid
All of the following terms describe the shape of a sound wave created by a tiny fragment of PZT except: A. spherical B. Huygen's wavelet C. v-shaped D. hourglass shaped
D. hourglass shaped
Two acoustic waves strike a boundary between two media. The waves are traveling in a direction of 90 degrees to the boundary. Reflection of these waves depends on differences in the _____. A. frequencies of two waves B. propagation speeds of the two media C. amplitudes of the two waves D. impedances of the two media
D. impedances of the two media
A sonographer adjusts the output power of the wave emitted by the transducer. Which of the following also changes? (more than one answer may be correct)
D. intensity
Which of the following terms best descries the relationship between frequency and wavelength for sound traveling in soft tissue?
D. inverse
Sound propagates from one medium with a density if 1.16 kg/m3 to a second medium with a density of 1.02 kg/m3. If the angle of transmission is 49 degrees, what can be correctly stated about the angle of incidence?
D. it cannot be determined
All of the following are true of the focus EXCEPT: A. it is at the end of the near zone B. it is at the beginning of the Fraunhofer zone C. it has the highest spatial peak intensity D. it is at the start of the Fresnel zone
D. it is at the start of the Fresnel zone
Which of the following describes the characteristics of a sound wave? A. longitudinal, non-mechanical B. mechanical, transverse C. transverse, acoustic D. mechanical, longitudinal
D. mechanical, longitudinal
Which term is reciprocal of mega? A. nano B. kilo C. macro D. micro
D. micro
An ultrasound wave approaches an interface between the two media at a 90 degree angle. The propagation speeds and the densities of the two media are different. Which is correct? A. reflection will definitely occur B. reflection will definitely not occur C. refraction may occur D. none of the above
D. none of the above
Which properties of the PZT crystal of a continuous wave transducer result in the highest emitted acoustic wave frequency? A. thin, high prop speed B. thick, slow prop speed C. thin, slow prop speed D. none of the above
D. none of the above
The angle between the direction of propagation and the boundary between two media is 90 degrees. What term describes the form of incidence of the wave? A. not normal B. direct C. oblique D. orthogonal E. multiply, stiffness, density
D. orthogonal
What is the pulse duration equals to?
D. period multiplied by the number of cycles in the pulse
The pulse repetition frequency is the
D. reciprocal of pulse repetition period
All of the following measure length EXCEPT A. mile B. inch C. mm D. second E. km
D. second
What remains when the reflected intensity is subtracted from the incident intensity?
D. transmitted intensity
Which of the following terms does NOT belong with the others? A. compression B. regions of high density C. regions of high pressure D. wide molecular spacing
D. wide molecular spacing
How thick is the active element of 3 MHz pulsed wave transducer?
Half the wavelength of the sound wave in PZT
The speed of sound traveling through bone is ________ soft tissue.
Higher than
What is the characteristic of acoustic waves with frequencies of less than 20 Hz when compared with waves having frequencies of more than 20 Hz?
Human can't hear them
Pulse duration is ______ related to bandwidth.
Inversely
The sensitivity of transducers that create short duration pulses is likely to be ________that of transducers that create long pulses
Less than
When a sonographer increases the maximum imaging depth during a exam, what happens to the PRF?
PRF decreases
You are given 5 substances: backing material, PZT, matching layer, gel, and skin, which impedances have been measured. Unfortunately, the labels identifying the impedance of each substance have fallen off these materials. There are five labels indicating impedances of 0.8 Mrayls, 1.9 Mrayls, 1.6 MRayls, 2.0 Mrayls, and 1.0 Mrayls, what are impedances of soft tissue, matching layer ,gel , and PZT? The impedances of the substances are: PZT _____ Matching layer _____ Gel ______ Skin__________
PZT (1.9) Matching layer (1.6) Gel (1.0) Skin (0.8)
Which of the following lists orders the impedance from highest to lowest
PZT, matching layer, gel, skin
A pair of 6 MHz probes are identical except for the active element diameters, which are 6 mm and 10 mm, respectively. Which beam will be more compact in the far field?
The 10 mm active element diameter
Two ultrasound systems are identical except for the diameter of the transducer's PZT crystal. Which system has the deepest focus?
The one with the large diameter crystal
Which component of an ultrasound system is made up of lead zirconate titanate?
Transducer's active element
True or false? Shorter duration events (such as dampened pulses) are more likely to be wide bandwidth.
True
Two ultrasound systems, one producing sound with a frequency of 3 MHz and the other at 6 MHz, are used to image a patient. The maximum imaging depth of both exams is 8 cm. Are the following 4 statements TRUE or FALSE? The pulses produced by both systems travel at the same speed in the patient
True
Two ultrasound systems, one producing sound with a frequency of 3 MHz and the other at 6 MHz, are used to image a patient. The maximum imaging depth of both exams is 8 cm. Are the following 4 statements TRUE or FALSE? The wavelength of the 3 MHz ultrasound is greater than the 6 MHz sound?
True
While imaging soft tissue. the spatial pulse length does not change as long as the components of the ultrasound system are the same (True or False)
True
What happens to determine the frequency of the sound produced by the transducers of a continuous wave ultrasound system?
Ultrasound system electronics
What is the shape of a sound beam created by a tiny piece of PZT?
V-shape
Which of these lists indicates media with decreasing attenuation of ultrasound?
Water, blood, fat, muscle, bone, air
A PZT crystal in the shape of a disc produces a continuous ultrasound wave. The beam is unfocused. Are the following 9 statements true or false? If the diameter of the sound beam is 8 mm at a depth equal to twice the near zone length, then the PZT crystal has a diameter of 16 mm.
false
A PZT crystal in the shape of a disc produces a continuous ultrasound wave. The beam is unfocused. Are the following 9 statements true or false? The near zone is the only region where the diameter of the sound is smaller then the transducer's.
false
A very high Q factor transducer is used more often in diagnostic imaging transducers than low Q factor
false
The acoustic impedance of the matching layer is approx. the same as the impedance of skin (True or false)
false
Two waves can have identical pulse repetition frequencies,, even if their pulse repetition periods are different (true or false)
false
In an imaging transducer, what is the purpose of attaching the backing material to PZT?
improves the image quality
Huygen's principle is based on
interference
What is the thickness of the matching layer of a 2 MHz pulsed wave transducer?
one-quarter the wavelength of sound in the matching layer
The intensity of an ultrasound beam is defined as the ______________ in the beam ______ by the _____________ of the beam.
power, divided, area
Damping material is secured to the PZT material during the fabrication of an ultrasonic imaging transducer. Which of the following is NOT a consequence of this attachment?
sensitivity increases
Which component of an ultrasound transducer is made form slab of epoxy embedded with tungsten particles? ew.
the damping material
Two systems are identical except for the frequency of the emitted pulse. Which system will have the deeper focus?
the higher frequency system
An ultrasonic pulse is traveling through soft tissue. Which of the following is most important in the determination of the frequency of the sound?
the propagation speed of the transducer's active element
A PZT crystal in the shape of a disc produces a continuous ultrasound wave. The beam is unfocused. Are the following 9 statements true or false? If the diameter of the sound beam is 8 mm at a depth of twice the near zone length, then the PZT crystal has a diameter of 8 mm.
true
A PZT crystal in the shape of a disc produces a continuous ultrasound wave. The beam is unfocused. Are the following 9 statements true or false? The far zone is the only region where the beam diameter exceeds the transducer diameter.
true
A sonographer using a 3 MHz transducer and increases the output power to visualize structures that are positioned deeper in patient. No other controls are adjusted. Would each of the following parameters increase, decrease, or remain the same? A. frequency B. wavelength C. power (initial) D. intensity (initial) E. pulse repetition frequency F. duty factor
A. frequency (same) B. wavelength (same) C. power (initial) (increase) D. intensity (initial) (increase) E. pulse repetition frequency (increase) F. duty factor (remains the same)
Which of the following 8 selections are acoustic variables? (true or false) A. frequency B. pressure C. propagation speed D. wavelength E. voltage F. intensity G. motion particle in a wave H. density
A. frequency (true) B. pressure (false) C. propagation speed (false) D. wavelength (false) E. voltage (false) F. intensity (true) G. motion particle in a wave (true) H. density (true)
All of the following correctly describe an imaging transducer EXCEPT A. high sensitivity B. low Q C. wide bandwidth D. damped
A. high sensitivity
If all the factors remain unchanged, what happens to the duty factor (increases, decreases, remains the same) when the pulse repetition frequency increases?
A. increases
A wave strikes an interface between two media and intensities are measured at the interface. What results when the reflected intensity is divided is divided by incident intensity? A. intensity reflection coefficient B. intensity transmission coefficient C. beam uniformity coefficient
A. intensity reflection coefficient
How is the weight related to a sonographer's time spent exercising? A. inversely B. conversely C. directly D. unrelated
A. inversely
What happens to a acoustic beam's intensity when the powers in the beam increases 25% while the cross sectional area of the beam remains the same? A. it increases by 25% B. it increases by 75% C. it increases by 50% D. it decreases by 25%
A. it increases by 25%
An acoustic wave is traveling from medium X into medium Z. Medium X has a propagation speed of 1,457 m/sec and an impedance of 1.44 Rayls. Medium Z as a propagation speed of 1,644 m/sec and an impedance of 1.26 Rayls. The angle of incidence is 32 degrees. What is true of the angle of the transmitted wave? A. it is greater than 32 degrees B. it is equal to 32 degrees C. it is less than 32 degrees D. cannot be determined
A. it is greater than 32 degrees
All of the following are true about transducer EXCEPT A. it is necessary to sterilize transducer before use B. most transducers simply require disinfection as they do not penetrate mucous membranes C. sterilization could depolarize PZT D. they are unlikely to trasmmit infection
A. it is necessary to sterilize transducer before use
Which of the following types of waves do not require a medium in order to propagate? (MORE THAN ONE ANSWER MAY BE CORRECT). A. light B. heat C. sound D. television
A. light B. heat D. television
What are the units associated with the circumference of a circle? A. mm B. mm^2 C. cm^3 D. m^4
A. mm
What are the units of the intensity reflection coefficient? A. none B. w/cm2 C. watts D. dB
A. none (it is a percentage)
The pulse duration is expressed in the same units as the
A. period
A sonographer is using a 3 MHz transducer and changes to 6 MHz transducer. The imaging depth remains unchanged. Would each of the following parameters increases, decreases, or remains the same? A. period B. frequency C. wavelength D. pulse repetition frequency
A. period (decrease) B. frequency (increases) C. wavelength (decrease) D. pulse repetition frequency (increase)
All of the following are acoustic parameters EXCEPT A. pressure B. period C. propagation of speed D. frequency
A. pressure
By changing the imaging depth, which if the following does the operator also change? (more than one answer may be correct) A. pulse repetition frequency B. duty factor C. propagation of speed D. pulse repetition period E. amplitude F. spatial pulse length
A. pulse repetition frequency D. pulse repetition period
While using the same ultrasound machine and transducer, which of the following can a sonographer alter? (more than one answer may be correct) A. pulse repetition period B. pulse repetition frequency C. frequency D. duty cycle E. pulse duration
A. pulse repetition period B. pulse repetition frequency D. duty cycle
A sonographer adjusts the maximum depth of an ultrasound system. Which of the following also changes? (more than one answer may be correct) A. pulse repetition period B. wavelength C. pulse repetition frequency D. frequency
A. pulse repetition period C. pulse repetition frequency
An ultrasound wave strikes an interface between two media at a 90 degree angle. The propagation speeds of the media are identical. However, the densities of the media are different. Which is true? A. reflection will definitely occur B. reflection will definitely not occur C. refraction may occur D. none of the above
A. reflection will definitely occur
What determines the period of an ultrasound wave?
A. the transducer
What establishes the frequency of an ultrasound wave? A. the transducer B. the medium through which the sound travels C. both a & b D. neither choice a or b
A. the transducer
The main purpose of a transducer's case are (more than one answer may be correct) A. to protect the patient from shock B. to protect the patient from heat C. to protect the internal components of the transducer D. to protect the patient from radiation
A. to protect the patient from shock C. to protect the internal components of the transducer
Using a particular ultrasound system and transducer, which of the following cannot be changed by the operator? A. wavelength B. intensity C. propagation speed D. amplitude (initial)
A. wavelength B. intensity C. propagation speed
What are the units of A. wavelength B. frequency C. intensity D. propagation of speed
A. wavelength (mm) B. frequency (H2) C. intensity (watts/cm^2) D. propagation of speed (meters/sec)
At what location is the sound beam diameter three times greater than the transducer diameter?
At the depth equal to four (two) focal length
How much bigger is one billion than one thousand? A. 1,000 times B. 1,000,000 times C. 10 times D. 10,000 times
B. 1,000,000 times
What are the units of pulse repetition frequency (PRF)?
B. 1/seconds
A sound wave is created by a transduce, reflects off an object, and returns to the transducer. The go-return time is 26 us. What is the depth of the reflector? A. 1 cm B. 2 cm C. 3 cm D. 4 cm
B. 2 cm
How many decibels represent a 100-fold increase in the intensity of an acoustic pulse? A. 10 B. 20 C. 100 D. 6
B. 20
Identify the wave that is ultrasonic A. 400 mHz B. 4 mHz C. 28 Hz D. 2 Hz
B. 4 MHz
How long does it take for sound to make a round trip to and from the skin's surface to a reflector depth of 1 cm in soft tissue?
13 usec
Typically, as an ultrasound wave travels through the soft tissue, the power of the wave
A. decreases
A sound wave with an intensity of 50w/cm^2 strikes a boundary and is totally reflected. What is the intensity reflection coefficient?
D. 100%
List these metric terms in decreasing order A. nano B. centi C. giga D. kilo E. hecto F. micro
1. giga 2. kilo 3. hecto 4. centi 5. micro 6. nano
What is the propagation speed of a 5 MHz sound wave in soft tissue?
1.54 mm/us
The impedance of a transducer's matching layer is 2.6 Mrayls and the impedance of the PZT is 3.4 Mrayls. If this is assumed to be a good imaging system, what is the best estimate for the impedance of the skin? A. 1.5 Mrayls B. 3.8 Mrayls C. 3.4 Mrayls D. 2.8 Mrayls
A. 1.5 MRayls
Of the four waves whose frequencies are listed below, which has the shortest period? A. 12 kHz B. 6.000 Hz C. 205 Hz D. 1 kHz
A. 12 kHz
The maximum value of density of an acoustic eave is 60 lbs/in^2, while then minimum density is 20 lbs/in^2. What is the amplitude of the wave?
A. 20 lb/in^2
The amplitude of an acoustic wave decreases from 27 pascals to 9 pascals. If the initial power in the wave is 27 watts, what is the wave's final power? A. 3 watts B. 9 watts C. 1 watt D. none of the above
A. 3 watts
Identify all the waves that are inaudible (more than 1 answer may be correct)
A. 4 MHz B. 400 kHz D. 2 Hz
A sound wave is created by a transducer, reflects off an object, and returns back to the transducer. The go-return time is 130 us. What is the maximum PRF? A. 7,700 Hz B. 5,000 kHz C. 10 cm D. 100 us
A. 7,700 Hz
Which of the following are considered acoustic parameters? (more than one answer may be correct)
A. Frequency E. Period
Which of the following explains the difference in sound beam shape created by a disc-shaped crystal from that of a small chip of PZT A. Huygens' principle B. Snell's law C. Bernoullis' law D. Murphy' law
A. Huygens' principle
What are the units of the transmitted intensity of a sound wave?
A. W/cm^2
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 from one location to another D. waves that are used to make images of anatomy
A. a series of compressions and rarefactions
Which of the following reports the relative strength of the ultrasound wave? A. decibels B. watts C. w/cm^2 d. pascals
A. decibels
As an ultrasound wave travels through the body, its amplitude usually:
A. decreases
The intensity of a signal declines from 1.5 w/cm^2 to 0.75 w/cm^2. How many decibels is this change in intensity?
D. -3 dB
What is a typical value for the duty factor (also called the duty cycle) of pulsed sound diagnostic imaging?
D. 0.001
What is the duty factor if the pulse duration is 1 us and the pulse repetition period is 1 ms?
D. 0.001
What is the reciprocal of 100? A. 0.1 B. 100 C. 0.2 D. 0.01 E. 1/50
D. 0.01
How many liters are contained in 80 ml of fluid? A. 8 B. 80 C. 0.008 D. 0.080
D. 0.080
What is the period of the earth's rotation around the sun? A. 1 day B. 1 hour C. 1 month D. 1 year
D. 1 year
The logarithm of a numerical value is defined as how many ________ must be multiplied together to get that numeral. A. 1 B. 2 C. 5 D. 10
D. 10
Which of the following actions would cause a PZT crystal to lose its special properties?
Exposing to high temperatures
A sonographer can adjust the duration of an acoustic pulse since it depends upon the pulse's propagation speed (True or False)
False
True or false? Refraction always occurs at the interface between two media when the propagation speeds of the media are unequal.
False
True or false? The period of a sound wave determines whether refraction will occur.
False
Two ultrasound systems, one producing sound with a frequency of 3 MHz and the other at 6 MHz, are used to image a patient. The maximum imaging depth of both exams is 8 cm. Are the following 4 statements TRUE or FALSE? The PRF of the 6 MHz transducer is greater than the PRF of the 3 MHz transducer
False
Two ultrasound systems, one producing sound with a frequency of 3 MHz and the other at 6 MHz, are used to image a patient. The maximum imaging depth of both exams is 8 cm. Are the following 4 statements TRUE or FALSE? The period of the 3 MHz sound is greater than the period if the 6 MHz sound.
False
