Physics Practice Exercise

What is the significance of grey scale variation in the spectrum of a pulsed wave Doppler display?

Question 1

Select one:

it determines the ensemble length

it represents the convergence of red blood cell lamina

it represents the velocity of red blood cells

it represents the number of red blood cells creating the reflection

it represents the speed of red blood cells

The correct answer is: it represents the number of red blood cells creating the reflection

An individual is supine. The blood pressure generated by the heart is 120 mmHg. What is the hydrostatic pressure at the ankle?

Question 2

Select one:

20 mmHg

220 mmHg

400 mmHg

0 mmHg

120 mmHg

The correct answer is: 0 mmHg

The thickness of a PZT crystal is _____ of the wavelength of sound in the PZT. The thickness of the matching layer is ________ of the wavelength of sound in the matching layer.

Question 3

Select one:

one-half, one-quarter

one-third, one-half

twice, one-quarter

one-half, twice

equal to, one-quarter

The correct answer is: one-half, one-quarter

Which of the components of attenuation is related to frequency raised to the fourth power?

Question 4

Select one:

Diffuse reflection

Backscatter

Refraction

Absorption

Rayleigh scattering

The correct answer is: Rayleigh scattering

All of the following are primarily used to change the overall brightness of an entire image EXCEPT:

Question 5

Select one:

compensation

output power

receiver gain

overall gain

amplification

The correct answer is: compensation

Improving the ability to measure the maximum velocity with Doppler is accomplished with all of the following EXCEPT:

Question 6

Select one:

increase the scale

increase the transducer's frequency

increase the pulse repetition period

use baseline shift

decrease the depth that you are sampling

The correct answer is: increase the transducer's frequency

All of the following artifacts place the erroneous reflection at the same depth as the true reflector EXCEPT"

Question 7

Select one:

side lobe

mirror image

refraction

grating lobe

The correct answer is: mirror image

How much bigger is a billion than a thousand?

Question 8

Select one:

1,000,000,000

100

10,000

1,000

1,000,000

The correct answer is: 1,000,000

Which component of an ultrasound system exposes the patient to the greatest risk?

Question 9

Select one:

pulser

transducer

spark autoregulator

beam former

high voltage display tube

The correct answer is: transducer

Which of these statements is most true of a 25 MHz sound pulse?

Question 10

Select one:

highly attenuating, extremely fast propagation speed, long wavelength

long period, short wavelength

short wavelength, lowly attenuating, slow speed

highly attenuating, short spatial pulse length

lowly attenuating, very deep half value layer, short period

The correct answer is: highly attenuating, short spatial pulse length

All of the following statements regarding in-vitro bioeffects are true EXCEPT:

Question 11

Select one:

In vitro bioeffects conclusions are clinically relevant

In vitro bioeffects are very important

in vitro bioeffects may not be applicable to clinical settings

In vitro bioeffects are always real

The correct answer is: In vitro bioeffects conclusions are clinically relevant

A pulse is emitted by a transducer and is travelling in soft tissue. The go-return time, or time-of-flight, of a sound pulse is 130 microseconds. What is the reflector depth?

Question 12

Select one:

10 cm

10 m

10 mm

130 mm

13 cm

The correct answer is: 10 cm

A circular hyperechoic structure is located at a depth of 5 cm. The structure has abnormally low attenuation and the speed of sound in the mass is 1,400 m/s. Which of the following artifacts is most likely to appear beneath the structure?

Question 13

Select one:

reflectors beneath the structure appear abnormally hyperechoic and too shallow

reflectors beneath the structure appear abnormally deep in the image

reflectors beneath the structure are hypoechoic and too shallow

subdicing

refraction artifact

The correct answer is: reflectors beneath the structure appear abnormally deep in the image

What does a hydrophone measure?

Question 14

Select one:

acoustic output of an ultrasound imaging system

attenuation of sound in soft tissue.

doppler frequency of a pulsed wave system

dynamic range of an ultrasound imaging system

receiver gain of an amplifier

The correct answer is: acoustic output of an ultrasound imaging system

Which of the following choices best describes axial resolution artifact?

Question 15

Select one:

a second copy of a true reflector appears deeper than the true reflector

two reflectors positioned one in front of the other appears as one reflection on the image

a hypoechoic region extending laterally along the focal zone

two reflectors positioned side-by side appears as one reflection on the image

The correct answer is: two reflectors positioned one in front of the other appears as one reflection on the image

Which of these terms does not belong with the others?

Question 16

Select one:

high PRF

short pulse duration

short pulse repetition period

high duty factor

shallow imaging

The correct answer is: short pulse duration

Which of the following best describes annular array transducers?

Question 17

Select one:

excellent axial resolution, diminished temporal resolution, rectangular shaped image

excellent contrast resolution, diminished temporal resolution, sector shaped image

excellent spatial resolution, diminished lateral resolution, sector shaped image

excellent lateral resolution, diminished temporal resolution, sector shaped image

excellent lateral resolution, diminished axial resolution, sector shaped image

The correct answer is: excellent lateral resolution, diminished temporal resolution, sector shaped image

An individual is standing. The blood pressure generated by the heart is 120 mmHg. What is the hydrostatic pressure at the ankle?

Question 18

Select one:

120 mmHg

400 mmHg

220 mmHg

20 mmHg

100 mmHg

The correct answer is: 100 mmHg

An ultrasound system is set at 0 dB and is transmitting at full intensity. What is the output power when the system is transmitting at 50% of full intensity?

Question 19

Select one:

-3 dB

-10 dB

-50 dB

10 dB

3 dB

The correct answer is: -3 dB

With an unfocused transducer, what is the area from the face of the transducer to where the beam diverges called?

Question 20

Select one:

focal zone

near field

far field

focal length

The correct answer is: near field

Which of the following transducers will have the shallowest focus?

Question 21

Select one:

low frequency, large diameter

high frequency, small diameter

high frequency, large diameter

low frequency, small diameter

The correct answer is: low frequency, small diameter

Which of the following statements related to venous flow is most correct?

Question 22

Select one:

During inspiration, venous flow in the arms decreases. During expiration, venous flow in the legs decreases.

During inspiration, venous flow in the arms increases. During expiration, venous flow in the legs increases.

During inspiration, venous flow in the arms decreases. During expiration, venous flow in the legs increases.

During inspiration, venous flow in the arms increases. During expiration, venous flow in the legs decreases.

The correct answer is: During inspiration, venous flow in the arms increases. During expiration, venous flow in the legs increases.

What conditions are required for refraction to occur at a boundary between two media?

Question 23

Select one:

oblique incidence and different impedances

different densities and different stiffness

oblique incidence and different speeds

normal incidence and different speeds

oblique incidence and different densities

The correct answer is: oblique incidence and different speeds

A shadow appears on an ultrasound scan. Which of the following statements is true about the structure immediately above the shadowing artifact?

speed of sound is too low

it is hypoechoic

there is too little absorption

attenuation properties are too high

speed of sound is too high

The correct answer is: attenuation properties are too high

Which of the following controls on an ultrasound system's console will reduce ghosting artifact?

Question 25

Select one:

impedance

wall filter

overall gain

Nyquist limit

persistence

The correct answer is: wall filter

Which of the following best describes the empirical approach to the study of bioeffects?

Question 26

Select one:

exposure-response

cause-effect

effect-microstreaming

risk-benefit

causation-reaction

The correct answer is: exposure-response

A sound beam is created by a single, disc-shaped crystal. Which of these beams has the shallowest focus?

Question 27

Select one:

6 MHz, 9 mm diameter

7 MHz, 9 mm diameter

5 MHz, 14 mm diameter

2 MHz, 9 mm diameter

5 MHz, 12 mm diameter

The correct answer is: 2 MHz, 9 mm diameter

The general mechanism which creates harmonics is called _____________.

Question 28

Select one:

Poiseulle's flow

Nyquist limits

non-linear behavior

Bernoulli flow

turbulent behavior

The correct answer is: non-linear behavior

All of the following are limitations of analog scan converters EXCEPT:

Question 29

Select one:

image deterioration over time

low spatial resolution

instability

image fade

image flicker

The correct answer is: low spatial resolution

Quality assurance studies should be performed ____________ .

Question 30

Select one:

daily

monthly

routinely

weekly

1 week prior to Joint Commission review

The correct answer is: routinely

A Doppler exam is performed with a 4 MHz transducer. The maximum Doppler shift is measured at 2.5 kHz. If the identical exam is performed with an 8 MHz transducer, what maximum Doppler shift will be measured?

Question 31

Select one:

1.25 kHz

2.5 kHz

4 kHz

8 kHz

5 kHz

The correct answer is: 5 kHz

The impedance of a transducer's active element is 1,900,000 rayls and the impedance of the skin is 1,400,000. What is an acceptable impedance for the matching layer?

Question 32

Select one:

1,407,000 rayls

1,200,000 rayls

1,726,444 rayls

2,400,000 rayls

1,900,000 rayls

The correct answer is: 1,726,444 rayls

Which of the following best describes a vector array transducer?

Question 33

Select one:

electronic steering, electronic focusing, sector shaped image

electronic steering, electronic focusing, trapezoidal shaped image

electronic steering, fixed focusing, trapezoidal shaped image

electronic steering, electronic focusing, rectangular shaped image

mechanical steering, electronic focusing, trapezoidal shaped image

The correct answer is: electronic steering, electronic focusing, trapezoidal shaped image

The interaction of microscopic bubbles and ultrasound form the basis for cavitation bioeffects. Which of the following forms of cavitation are most likely to produce microstreaming in the intracellular fluid and shear stresses?

Question 34

Select one:

inertial cavitation

active cavitation

transient cavitation

stable cavitation

normal cavitation

The correct answer is: stable cavitation

Under which of the following conditions is axial resolution improved?

Question 35

Select one:

decreased pulse amplitude

decreased imaging depth

decreased spatial pulse length

decreased beam diameter

decreased pixel size

The correct answer is: decreased spatial pulse length

A Doppler exam is performed with a 5 MHz transducer. The maximum Doppler shift is measured at 2.5 kHz. If the identical exam is performed with a 2.5 MHz transducer, what maximum Doppler shift will be measured?

Question 36

Select one:

5 kHz

8 kHz

4 kHz

2.5 kHz

1.25 kHz

The correct answer is: 1.25 kHz

Under which circumstance is cavitation most likely to occur?

Question 37

Select one:

high frequency and low power

high intensity and high frequency

low frequency and high signal amplitude

low intensity and low frequency

The correct answer is: low frequency and high signal amplitude

What is displayed on the x-axis of an m-mode image?

Question 38

Select one:

echo intensity

time

time-of-flight

reflector depth

red blood cell velocity

The correct answer is: time

All of the following result from the use of backing material in a transducer EXCEPT:

Question 39

Select one:

wide bandwidth

low Q-factor

high sensitivity

reduced spatial pulse length

shorter pulse duration

The correct answer is: high sensitivity

Which of the following best describes the features of a sound wave and medium that determine the speed of sound in the medium?

Question 40 Select one:

pulse repetition period of the sound wave and density of the medium

elasticity of the medium and frequency of the sound beam

density of the medium and stiffness of the medium

density of the medium and power of the sound beam

stiffness of the medium and elasticity of the medium

The correct answer is: density of the medium and stiffness of the medium

The image on an ultrasound system's display is too dark. Which of the following techniques is best to correct this problem?

Question 41 Select one:

increase reject

increase threshold

increase receiver gain

adjust time gain compensation

increase power

The correct answer is: increase receiver gain

All of the following are true EXCEPT:

Question 42 Select one:

Out-of-phase waves interfere destructively

Constructive interference is associated with waves that are in-phase.

Two waves with identical frequencies must interfere constructively.

Waves of different frequencies may exhibit both constructive and destructive interference at different times.

The correct answer is: Two waves with identical frequencies must interfere constructively.

What is the accuracy of reflector depth position on an A-mode, B-mode or M-mode display called?

Question 43 Select one:

range resolution

depth calibration

speed error artifact

axial resolution

horizontal calibration

The correct answer is: depth calibration

All of the following terms are associated with PACS systems EXCEPT:

Question 44 Select one:

large capacity storage devices

easy access to archived studies

analog replay

store and forward telemedicine

The correct answer is: analog replay

Which of the following situations should result in a cessation of the use of diagnostic ultrasound?

Question 45 Select one:

the benefits are outweighed by the risks

the benefit outweighs the risk

when tissue temperature is more than 1 degree Centigrade above normal

when a pregnant mother has a very high fever

the presence of transient cavitation

The correct answer is: the benefits are outweighed by the risks

Spatial resolution is determined by which of the following?

Question 46 Select one:

beam diameter

spatial pulse length

the number of bits per pixel

frame rate

the number of pixels per inch

The correct answer is: the number of pixels per inch

Which of the following sound waves is ultrasonic and least useful in diagnostic imaging?

Question 47 Select one:

8 MHz

15 Hz

3,000 kHz

30 KHz

8,000 Hz

The correct answer is: 30 KHz

The electronics within the ultrasound receiver reduces the amplitude dynamic range by 20 dB. What is the compressed dynamic range it the uncompressed dynamic range was 100 dB

Question 48 Select one:

-3 dB

120 dB

5 dB

80 volts

80 dB

The correct answer is: 80 dB

All of the following are true of sound waves EXCEPT:

Question 49 Select one:

they are mechanical, transverse waves

they are comprised of rarefactions and compressions

Sound waves carry energy from one location to another

Regions of rarefaction are associated with lower pressure and lower density.

Sound waves can create bioeffects.

The correct answer is: they are mechanical, transverse waves

Which of the following transducers will create a sound beam with the least amount of divergence in the far field?

Question 50 Select one:

high frequency, large diameter

large diameter, thick crystal

small diameter, low frequency

small diameter, thin crystal

thin crystal, high frequency

The correct answer is: high frequency, large diameter

Which of the following adjustments will increase the signal-to-noise ratio?

Question 51 Select one:

increasing output power

increase PRF

decreasing amplification

decreasing depth gain compensation

decrease reject

The correct answer is: increasing output power

The image on an ultrasound system's display is too bright. Which of the following techniques is best to correct this problem?

Question 52 Select one:

decrease receiver gain

increase threshold

adjust time gain compensation

decrease reject

decrease output power

The correct answer is: decrease output power

An individual is standing. The blood pressure generated by the heart is 120 mmHg. What pressure will be measured at the ankle?

Question 53 Select one:

400 mmHg

100 mmHg

220 mmHg

120 mmHg

20 mmHg

The correct answer is: 220 mmHg

A sound wave's frequency is 10 MHz. The wave is travelling in soft tissue. What is its wavelength?

Question 54 Select one:

1.54 mm

0.15 mm

0.77 mm

10 MHz

15.4 mm

The correct answer is: 0.15 mm

Which of the following best describes a linear sequential array transducer?

Question 55 Select one:

mechanical steering, electronic focusing, trapezoidal shaped image

electronic steering, electronic focusing, trapezoidal shaped image

electronic steering, electronic focusing, sector shaped image

dynamic receive focusing, rectangular shaped image

electronic steering, fixed focusing, trapezoidal shaped image

The correct answer is: dynamic receive focusing, rectangular shaped image

Which of these factors has the greatest influence on pulse repetition period?

Question 56 Select one:

thickness of the PZT crystal

attenuation of the sound beam

display depth

display's dynamic range.

impedance of the medium

The correct answer is: display depth

A sound wave with a frequency of 5 MHz is travelling in soft tissue. What is the wavelength of this sound?

Question 57 Select one:

5 mm

0.3 cm

0.5 mm

0.3 mm

0.5 m

The correct answer is: 0.3 mm

What determines whether reflection will occur when a sound beam strikes a boundary at normal incidence?

Question 58 Select one:

incident differences

impedance differences

propagation speed differences

elasticity differences

density differences

The correct answer is: impedance differences

Which of the following statement about Doppler is most correct?

Question 59 Select one:

non-directional Doppler uses FFT processing, while bi-directional Doppler uses Nyquist processing

non-directional Doppler uses phase-quadrature processing, while bi-directional Doppler uses coherent processing

non-directional Doppler uses phase-singular processing, while bi-directional Doppler uses phase-quadrature processing

non-directional Doppler uses non-coherent processing, while bi-directional Doppler uses phase-quadrature processing.

non-directional Doppler uses autocorrelation processing, while bi-directional Doppler uses phase-quadrature processing

The correct answer is: non-directional Doppler uses non-coherent processing, while bi-directional Doppler uses phase-quadrature processing.

Which of the following best describes demodulation of electronic signals?

Question 60 Select one:

inserting negative voltages into the signal

reducing the noise content of a signal

increasing the dynamic range of the signal

changing the shape or form of the signal

The correct answer is: changing the shape or form of the signal

Which of these biologic tissues will sound waves propagate most quickly?

Question 61 Select one:

fat

tendon

blood

lung

amniotic fluid

The correct answer is: tendon

Under which of the following conditions is lateral resolution improved?

Question 62 Select one:

decreased imaging depth

decreased beam diameter

decreased pixel size

decreased pulse duration

decreased spatial pulse length

The correct answer is: decreased beam diameter

The following transducers have a constant output power. Which of the following will have the lowest SPTA intensity at a depth of one near zone?

Question 63 Select one:

4 MHz, 10 mm diameter

4 MHz, 9 mm diameter

4 MHz, 12 mm diameter

4 MHz, 4 mm diameter

4 MHz, 6 mm diameter

The correct answer is: 4 MHz, 12 mm diameter

Which of the following is associated with power mode Doppler?

Question 64 Select one:

flash artifact and reduced sensitivity

high sensitivity and high frame rates

good temporal resolution and flash artifact

lower sensitivity and good temporal resolution

poor temporal resolution and flash artifact

The correct answer is: poor temporal resolution and flash artifact

Which of the following steps is performed just prior to storage of image data in a digital scan converter?

Question 65 Select one:

D-to-A conversion

A-to-D conversion

demodulation

rectification

read magnification

The correct answer is: A-to-D conversion

Which of the following is the spectral analysis technique of choice for pulsed and continuous wave Doppler?

Question 66 Select one:

fast Fourier transform

correlation function for pulsed Doppler, zero crossing detection for continuous wave Doppler

autocorrelation for pulsed Doppler; fast Fourier transform for continuous wave Doppler

fast Fourier transform for pulsed Doppler; autocorrelation for continuous wave Doppler

autocorrelation for pulsed Doppler and continuous wave Doppler

The correct answer is: fast Fourier transform

Which of the following terms does not belong with the others?

Question 67 Select one:

parabolic flow

turbulent flow

laminar flow

plug flow

layered flow

The correct answer is: turbulent flow

How much time is required for a sound pulse to travel round trip to and from a reflector that is 2 cm deep in soft tissue?

Question 68 Select one:

2 s

0.26 s

26 ms

26 us

26 s

The correct answer is: 26 us

Which of these terms does not belong with the others?

Question 69 Select one:

gray scale

wide dynamic range

few choices

uncompressed signal

low contrast

The correct answer is: few choices

With an unfocused transducer, what is the narrowest part of the beam where it starts to diverge called?

Question 70 Select one:

near field

focal zone

focal length

focus

far field

The correct answer is: focus

All of the following correctly describe dynamic range EXCEPT:

Question 71 Select one:

logarhythmic

ratio

relative

absolute

comparison

The correct answer is: absolute

Which of these terms means 'many gray shades?'

Question 72 Select one:

few choices

wide dynamic range

highly compressed signal

high contrast

bistable

The correct answer is: wide dynamic range

You are performing a Doppler interrogation of the carotid artery of a patient with a history of CVA. At what Doppler angle is the velocity estimate most accurate?

Question 73 Select one:

60 degrees

30 degrees

zero degrees

90 degrees

45 degrees

The correct answer is: zero degrees

In a B-mode display, which of the following CRT inputs are used with the amplitude of the reflection?

Question 74 Select one:

time base axis

y-axis

x-axis

z-axis

m-axis

The correct answer is: z-axis

Which of the following user-adjustable controls has the single greatest affect upon Doppler color jet size?

Question 75 Select one:

red blood cell velocity

packet size

doppler/echo read write priority

ensemble length

color Doppler gain settings

The correct answer is: color Doppler gain settings

All of the following operational settings are related to improved temporal resolution EXCEPT:

Question 76 Select one:

low line density

shallower imaging

narrow sector

increased frequency

single focus

The correct answer is: increased frequency

All of the following statements regarding the hemodynamics of a stenosis are true EXCEPT:

Question 77 Select one:

pressure is highest upstream from the stenosis

turbulence is evident downstream from the stenosis

flow direction changes as blood flows into and out of the stenosis

in cases of significant stenosis, the flow pattern downstream from the stenosis may be steady rather than pulsatile

velocity is highest downstream from the stenosis

The correct answer is: velocity is highest downstream from the stenosis

All of the following statements are true regarding mirror image artifact EXCEPT:

Question 78 Select one:

mirror image is created by reflection

a strong reflector appears on the image

a second copy of an actual reflector appears on the image

the distance between the artifact and the mirror is the same as the distance between the true reflector and the image

the artifact appears at the same depth as the true reflector

The correct answer is: the artifact appears at the same depth as the true reflector

Which of the following factors determine the spatial resolution of a monitor?

Question 79 Select one:

the number of lines per frame

the number of pixels per bit

dynamic range

the number pixels per inch

the number of bits per inch

The correct answer is: the number of lines per frame

All of the following are related to dedicated continuous wave transducers EXCEPT:

Question 80 Select one:

high sensitivity

high Q-factor

undamped crystal

requires at least 2 crystals in the probe

wide bandwidth

The correct answer is: wide bandwidth

In which of these media will sound travel the slowest?

Question 81 Select one:

low density, high stiffness

high density, low elasticity

low density, low stiffness

high density, high stiffness

high density, low stiffness

The correct answer is: high density, low stiffness

A shadow appears on an ultrasound scan. Which of the following statements is true about the shadow artifact?

Question 82 Select one:

it appears as hypoechoic

attenuation properties are too low

speed of sound is too low

speed of sound is too high

there is too little absorption

The correct answer is: it appears as hypoechoic

All of the following statements regarding the hemodynamics of a stenosis are true EXCEPT:

Question 83 Select one:

flow direction changes as blood flows into and out of the stenosis

pressure is lowest downstream from the stenosis

turbulence is evident downstream from the stenosis

velocity is highest within the stenosis

in cases of significant stenosis, the flow pattern downstream from the stenosis may be steady rather than pulsatile

The correct answer is: pressure is lowest downstream from the stenosis

When a sound beam bounces off a reflector at an oblique angle, the angle of reflection is equal to the angle of incidence. What is this called?

Question 84 Select one:

Bernoulli's Principle

Poiseuille's Law

Snell's Law

there is no special name for this

Edelman's Law

The correct answer is: there is no special name for this

Which of the following best describes the mechanistic approach to the study of bioeffects?

Question 85 Select one:

effect-microstreaming

causation-reaction

cause-effect

risk-benefit

exposure-response

The correct answer is: cause-effect

Which of the following is most likely to create cavitation?

Question 86 Select one:

low peak pressure and long wavelength

high peak rarefaction pressure and low frequency

high peak pressure and short wavelength

high peak pressure and high frequency

The correct answer is: high peak rarefaction pressure and low frequency

With phased array transducers, tiny time delays are used to steer the sound beams in different directions. Which component of an ultrasound system creates these time delays?

Question 87 Select one:

beam former

receiver

demodulator

preprocessor

transducer

The correct answer is: beam former

Which of the following statements is true regarding color flow Doppler?

Question 88 Select one:

color flow is a pulsed ultrasound technique that is not subject to aliasing artifact

color flow is a continuous wave ultrasound technique that is subject to aliasing artifact

color flow is a pulsed ultrasound technique that is subject to aliasing artifact

color flow is a continuous wave ultrasound technique that is not subject to aliasing artifact

The correct answer is: color flow is a pulsed ultrasound technique that is subject to aliasing artifact

Which of the following choices best describes an ideal epidemiologic bioeffects study?

Question 89 Select one:

prudent and safe

ideal and non-biased

randomized and prospective

benefits outweigh the risks

retrospective and optimized

The correct answer is: randomized and prospective

What is the greatest advantage of one and one-half dimensional array transducers?

Question 90 Select one:

improved axial resolution

improved slice thickness resolution

improved temporal resolution

improved lateral resolution

improved contrast resolution

The correct answer is: improved slice thickness resolution

Which of the following forms of focusing is achieved during reception?

Question 91 Select one:

internal

lens

excitation phasing

dynamic aperture

external

The correct answer is: dynamic aperture

In a real time scanner, which of these choices determines the maximum frame rate?

Question 92 Select one:

lateral resolution

beam diameter

pixel size

depth of view

attenuation coefficient

The correct answer is: depth of view

Which of the following choices determines the signal amplitude in the transducer of an ultrasound system?

Question 93 Select one:

edge enhancement filtering

demodulation

persistence

post processing

reflected intensity of the sound beam

The correct answer is: reflected intensity of the sound beam

Which of the following will result in the greatest number of shades of gray in a digital image display?

Question 94 Select one:

narrow dynamic range

large pixels with many bits/pixel

small pixels with few bits/pixel

many TV lines per frame

high contrast

The correct answer is: large pixels with many bits/pixel

All of the following are true of normal cavitation EXCEPT:

Question 95 Select one:

temperatures in the thousands of degrees is created

it is consistent with shock waves

it is also known as inertial cavitation

harmful bioeffects are commonly observed

only a 10% increase in pressure is needed to convert to this from stable cavitation

The correct answer is: harmful bioeffects are commonly observed

Which of the following is not used to measure the output of ultrasound systems?

Question 96 Select one:

hydrophone

calorimeter

thermocouple

liquid crystals

calibrated absorpterometer

The correct answer is: calibrated absorpterometer

Under which of the following conditions is axial resolution improved?

Question 97 Select one:

decreased pulse amplitude

decreased pixel size

decreased pulse duration

decreased beam diameter

decreased imaging depth

The correct answer is: decreased pulse duration

Which of the following lists is in decreasing order?

Question 98 Select one:

deci, deca, nano, milli, mega, hecto

nano, micro, milli, kilo

mega, macro, milli, nano, pico

mega, nano, deci, deca, micro

kilo, hecto, deci, milli, micro, nano

The correct answer is: kilo, hecto, deci, milli, micro, nano

Which of the following is the correct order of receiver operation?

Question 99 Select one:

amplification, demodulation, reject

amplification, compression, compensation, demodulation, reject

attenuation, amplification, TGC, gain, threshold

reject, demodulation, compression, compensation, amplification

amplification, compensation, compression, reject, demodulation

The correct answer is: amplification, demodulation, reject

At what location in a sound beam is the SPTA intensity the highest?

Question 100 Select one:

half value depth

Fraunhofer zone

Fresnel zone

focal zone

focal point

The correct answer is: focal point