Physics

Density and Speed

Opposite Direction Density is related to weight

This measurement of intensity is averaged only during the pulse duration (on time only)

PA Peak Average

PRF is the reciprocal of ____

PRP

What component of a transducer changes electrical to mechanical and mechanical back to electrical energy?

PZT

Name the 5 values that are determined by the source

Period Frequency Amplitude Power Intensity

Name the 7 parameters that describe a sound wave

Period Frequency Amplitude Power intensity Propagation Speed Wavelength

What is absorption (from attenuation)

Sound energy converted into heat energy

The decrease in intensity, power, and amplitude as the sound waves travels is termed what?

Attenuation

This value is higher in both bone and lung compared to soft tissue

Attenuation

The amount of attenuation per centimeter (dB/cm) is known as what?

Attenuation coefficient

When the path length changes this coefficient does not change

Attenuation coefficient

How many bits are needed to represent 1024 gray shades? A. 1024 B. 8 C. 10 D. 3 E. 512

C. 10

What is the most typical Doppler shift measured clinically? A. 3.5MHz B. 3,500,000Hz C. 2kHz D. 1,000kHz E. 20,000Hz

C. 2kHz

What is the formula to calculate frequency

F= C/wavelength

Penetration and axial resolution are related to what sound wave characteristic?

Frequency

What is the formula for impedance?

Impedance (rayls)= density (kg/m3) X propagation speed (m/s)

In soft tissue, the attenuation coefficient (dB/cm) is estimated at approximately what value?

Half of the frequency

With an increase speed what change do we see in the density?

Increased

If intensity decreases, what happens to the propagation speed?

Increases

If stiffness increases, what happens to the propagation speed?

Increases

What is the formula for intensity?

Intensity = Power / Area

______ is the distance covered by one cycle. a. pulse length b. wavelength c. cycle duration d. cycle duration

b. wavelength

The effects of ultrasound upon tissue are called

bioeffects

3 acoustic variables

pressure density distance

what are attenuation's three components?

scattering, reflection, absorption

(True or False) Speed increases as frequency increases

false

Pertaining to the original intensity v.s the final intensity what does 20dB mean?

10 X 10 x the final is 100 times greater than the original

What is the propagation speed in soft tissue?

1,540 m/s 1.54 km/s 1.54 mm/us (millimeters per microsecond)

Pertaining to the original intensity v.s the final intensity what does 6dB mean?

2 X 2 x the final is 4 times greater than the original

Pertaining to the original intensity v.s the final intensity what does 3dB mean?

2 X the final intensity is 2 times greater than the original intensity

What are typical clinical Doppler frequencies? A. 1- 10,000Hz B. 1- 10MHz C. 2- 1,000kHz D. 40- 45kHz

A. 1- 10,000Hz

Which of the following waves is ultrasonic and most useful in diagnostic imaging? A. 2,455,000 Hz B. 100 Mhz C. 2.4 kHz D. 14,000 Hz

A. 2,455,000 Hz

Does the medium or the sound source determine the following parameters? A. Wavelength B. Frequency C. Intensity D. Propagation Speed E. Period F. Power

A. Both B. Sound source C. Sound Source D. Medium E. Sound Source F. Sound Source

Using a particular ultrasound system and transducer, which of the following cannot be changed by the operator? A. Wavelength B. Amplitude C. Intensity D. Propagation Speed E. Period F. Power

A. Cannot B. Can C. Can D. Cannot E. Cannot F. Can

In a real time scanner, which of these choices determines the maximum frame rate? a. depth of view b. pixel size c. attenuation coefficient d. beam diameter e. lateral resolution

A. Depth of view

What happens to the speed of the sound in a medium when the bulk modulus increases? A. Faster B. Slower C. Remains the same

A. Faster Bulk modulus is another way to say stiffness

All of the following will improve temporal resolution EXCEPT: A. Increased line density B. Single rather than multi focus C. Higher frame rate D. Shallower depth of view E. Slower speed of sound in a medium

A. Increased line density

when changing the imaging depth, which parameters does the operator also change? A. PRF (pulse repetition frequency) B. duty factor C. propagation speed D. pulse repetition period E. amplitude F. spatial pulse length

A. PRF B. duty factor D. pulse repetition period

Which of the following has the greatest influence on temporal resolution? a. propagation speed and the imaging depth b. frequency of sound and the propagation c. wavelength of sound and propagation speed d. output power and frequency

A. Propagation speed and the imaging depth

The angle of incidence of an ultrasound beam is perpendicular to an interface. The two media have the same propagation speeds. What process cannot occur? A. Refraction B. Reflection C. Transmission D. Attenuation

A. Refraction

What is the significance of gray scale variation in the spectrum of a pulsed wave Doppler display? A. it represents the number of red blood cells creating the reflection B. it represents the velocity of red blood cells C. it represents the speed of red blood cells D. It represents the convergence of red blood cell lamina E. It determines the ensemble length

A. it represents the number of red blood cells creating the reflection

Which of the following waves has the longest wavelength? A. low frequency B. low amplitude C. high frequency D. high intensity

A. low frequency

From a safety standpoint, which one of the following methods is best? A. low transmit output and high receiver gain B. high transmit output and low receiver gain C. high near gain and low far gain D. low near gain and high far gain E. high reject and high transmitter output

A. low transmit output and high receiver gain

What are the units of the following parameters: A. Wavelength B. Frequency C. Intensity D. Propagation Speed E. Period F. Power

A. millimeters B. Hertz C. watts/cm2 D. meters/sec E. second F. watts

What parameters describes a sound beams strength?

Amplitude Power Intensity

An ultrasound wave travels through two media and has attenuation of 3 dB in the first and 5 dB in the second. What is the total attenuation? A. 15 dB B. 8 dB C. 3 / 5 dB D. 5 / 8 dB

B. 8 dB

Multiple reflectors that are equally spaced are called: a. refractions b. reverberations c. shadows d. comets

B. Reverberations

If intensity remains the same while the power is doubled, what has happened to the beam area? A. quadrupled B. doubled C. halved D. unchanged

B. doubled

Which of the following characteristics will create 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

Images on a videotape are stored used: A. magic B. magnetism C. paper D. computer memory

B. magnetism

**Where are harmonics created? A) in the receiver B) in the transducer C) in the tissues D) in the beam former

C) in the tissues

According to the AIUM statement on bioeffects, there have been no confirmed bioeffects below intensities of ____________ watts per square centimeter SPTA. A. 10 B. 0.01 C. 0.1 D. 1 E. 100

C. 0.1

The power in a beam is 1 watt and the area is 5cm2. What is the beam's intensity? A. 5 W/cm2 B. 1 W/cm2 C. 0.2 W/cm2 D. 1 watt

C. 0.2 W/cm2

A sound beam travels a total of 10cm in 2 seconds. What is the speed of the sound in this medium? A. 10 cm/sec B. 2 cm/sec C. 5 cm/sec D. 0.2 cm/sec

C. 5 cm/sec

If a manufacturer changed the lines per frame and kept the imaging depth the same, what else would change? a. PRF b. period c. frame rate

C. Frame rate

A quality assurance program: A. Is not needed in small labs B. Is very time consuming and expensive C. Is needed by all labs D. Cannot be performed by sonographers

C. Is needed by all labs

Which of the following is proportional to the square of the amplitude? A. Period B. Attenuation C. Power D. Frequency E. Speed

C. Power

Volume has which of the following units? A. cm B. cm2 C. cm3 D. cm4

C. cm3

Assuming a constant frequency, what happens if the diameter of an unfocused circular transducer is increased? A. the distance to the far field is reduced B. the beam width in the near field is reduced C. the beam width in the near field is increased D. the ultrasound wavelength is increased E. the sensitivity is reduced

C. the beam width in the near field is increased

What is the formula to calculate propagation speed?

C= wavelength X F

Attenuation of ultrasound in soft tissue is closest to: A. 3 dB/ 1MHz B. 1 dB/ cm/ 10MHz C. 2 dB/ cm D. 0.6 dB/ cm / MHz

D. 0.6 dB/ cm/ MHz

The distance to a target is doubled. The time-of-flight for a pulse to travel to the target and back is: A. 4 times B. 8 times C. The same D. 2 times

D. 2 times

Which of the following waves is ultrasonic and least useful in diagnostic imaging? A. 8 MHz B. 2.5 MHz C. 18,000 Hz D. 24,000 Hz E. 3,000,000 Hz

D. 24,000 Hz

*** What Doppler angle is most inaccurate? A. 15- 30 degrees B. 30-45 degrees C. 45- 60 degrees D. 60- 75 degrees

D. 60- 75 degrees

What is the actual time that an ultrasound machine is creating a pulse? A. Duty factor B. Period C. Pulse period D. Pulse duration

D. Pulse duration

Fill-in of an anechoic structure such as a cyst is known as all of the following EXCEPT: A. partial volume artifact B. slice thickness artifact C. section thickness artifact D. ghosting artifact

D. ghosting artifact

Which of the following waves will have the shortest wavelength? A. low frequency traveling in a fast medium B. low frequency traveling in a slow medium C. high frequency traveling in a fast medium D. high frequency traveling in a slow medium

D. high frequency traveling in a slow medium

What component of the ultrasound unit contains the memory bank? A. transducer B. receiver C. display D. scan converter

D. scan converter

Units for attenuation are?

DB (must be negative, since the attenuation causes intensity to decrease)

If stiffness decreases, what happens to the propagation speed?

Decreases

In intensity increases, what happens to the propagation speed?

Decreases

What is the formula for density?

Density = mass/volume

What two conditions must be met for refraction to occur?

Differing propagation speeds and an oblique incidence

Changing which of the following would not cause any change in a hard copy image output? A. TGC B. Overall gain C. Output power D. Display brightness & contrast E. Depth of view

Display brightness & contrast

What is the range of frequencies created by medical diagnostic Doppler transducers? A. 4- 10Hz B. 10- 20MHz C. 1- 10kHz D. 2- 20Hz E. 2- 10MHz

E. 2- 10MHz

The relative output of an ultrasound instrument is calibrated in dB and the operator increases the output by 60 dB. The beam intensity is increased by which of the following? A. 5% B. two times C. twenty times D. one hundred times E. one million times

E. one million times

Which of the following sets of properties of a test phantom is most relevant when assessing depth calibration accuracy? A. reflector spacing and reflection coefficient B. attenuation and speed of ultrasound in the medium C. reflector spacing and ultrasound attenuation in the medium D. reflector reflection coefficient and ultrasound attenuation in the medium E. reflector spacing and propagation speed

E. reflector spacing and propagation speed

What will cause impedance to increase?

Either an increase in density or an increase in propagation speed

(True or False) A sonographer's education ends when they become registered

False

(True or False) Doppler shifts always occur if the sound source and receiver are in motion.

False

(True or False) If the amplitude of a wave is increased to 3 times its original value, the intensity is increased by 6 times.

False

(True or False) If the power of a wave is halved, the intensities reduced to one-fourth its original value.

False

(True or False) Lateral resolution is also called: Axial

False

(True or False) Lateral resolution is also called: longitudinal

False

(True or False) Lateral resolution is also called: range

False

(True or False) The sonographer cannot change, directly or indirectly, the duty factor of an US machine.

False

(True or False) There have not been biological effects from US found in the laboratory.

False

(True or False) With right angle incidence, reflections are always generated at a boundary if the propagation speeds of the media are different.

False

(True/False) With normal incidence the angle is 180 degrees.

False

True or False Doppler shifts are always created when the source and receiver are in motion relative to each other.

False

True or False Sonographers cannot affect a patient's exposure to acoustic energy.

False

True or False The manufacturer increases the number of lines per frame. As a result, which of the following may have to be decreased? Frequency

False

True or False The manufacturer increases the number of lines per frame. As a result, which of the following may have to be decreased? Power output

False

True or False. Axial resolution is affected by focusing.

False

True or False. Increasing the frequency increases the penetration depth.

False

(True or False) Sound is a transverse, mechanical wave

False Sound is a mechanical longitudinal wave

In soft tissue if we increase the frequency what happens to the attenuation?

It increases (Frequency and attenuation have a direct relationship. This is why we do not image deep with high frequency sound)

What can increase the pulse duration of a transducer?

Lower the Frequency (longer period) Increase the cycles in a pulse (more ringing)

5 additional parameters needed to completely describe *pulsed sound*

Pulse Duration Pulse Repetition Period PRF Duty Factor Spatial Pulse Length

Pulse Duration Equation

Pulse Duration (us) = # cycles in pulse X period (us)

___________ is the time from the start of a pulse to the end of that pulse.

Pulse duration

____________ is the time from the start of a pulse to the start of the next pulse.

Pulse repetition Period

Sound waves are comprised of what?

Rarefactions and Compressions

This measurement of intensity has the lowest value

SATA Spatial Average Temporal Average

Spatial Pulse Length Equation

SPL(mm) = # of cycles X wavelength (mm)

This measurement of intensity is the most relevant to tissue heating

SPTA Spatial Peak Temporal Average

This intensity has the highest value

SPTP Spatial Peak Temporal Peak

The rank of intensities from the largest to the smallest

SPTP > IM > SPPA > SPTA > SATA

Stiffness and Speed

Same Direction Stiffness is related to change in shape, "squshability"

This measurement of intensity is averaged during the pulse repetition period (both on and off times)

TA Temporal Average

This measurement of intensity is maximum in time

TP Temporal Peak

The propagation speed is determined by what?

The medium

This is determined by both the sound source and the medium

The wavelength

(True or False) A sound wave is a pressure wave made of compressions and rarefactions.

True

(True or False) A system which was working well now does not display clear images in the far field. This may be a problem with the monitor

True

(True or False) A system which was working well now does not display clear images in the far field. This may be a problem with the receiver

True

(True or False) A system which was working well now does not display clear images in the far field. This may be a problem with the scan converter

True

(True or False) A system which was working well now does not display clear images in the far field. This may be a problem with the transducer

True

(True or False) Lateral resolution is also called: azimuthal

True

(True or False) Shadowing may result from high amounts of reflection of US energy.

True

True or False Gray scale can be changed by the sonographer?

True

True or False The manufacturer increases the number of lines per frame. As a result, which of the following may have to be decreased? Frame rate

True

True or False The manufacturer increases the number of lines per frame. As a result, which of the following may have to be decreased? Imaging depth

True

True or False The manufacturer increases the number of lines per frame. As a result, which of the following may have to be decreased? Sector angle

True

(True or False) A wave with a frequency of 15,000 MHz is ultrasonic

True Ultrasound is defined as a wave with a frequency of greater than 20,000 Hertz.

Reflection occurs when what happens?

When some of the propagation sound energy strikes a boundary between two media and is returned toward the transducer

*** 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? a. -3 dB b. -50 dB c. 10 dB d. 3 dB e. -10 dB

a. -3 dB

A sound wave's frequency is 10 MHz. The wave is traveling in soft tissue. What is its wavelength? a. 0.15 mm b. 1.54 mm c. 15.4 mm d. 0.77 mm e. 10 MHz

a. 0.15 mm

What is the approximate attenuation coefficient of 1 MHz US in soft tissue? a. 0.5dB/cm b. 1 cm c. 3dB/cm d. 1dB

a. 0.5dB/cm

A pulse is emitted by a transducer and is traveling in soft tissue. The go-return time, or time-of-flight, of a sound pulse is 130 microseconds. What is the reflector depth? a. 10 cm b. 10 mm c. 10 m d. 130 mm e. 13 cm

a. 10 cm

Which of the following sound waves is ultrasonic and least useful in diagnostic imaging? a. 30 KHz b. 8 MHz c. 8,000 Hz d. 3,000 kHz e. 15 Hz

a. 30 KHz

Sound intensity is decreased by 75%. How many decibels of attenuation is this? a. 6dB b. 9dB c. 5dB d. 10dB

a. 6dB

All of the following statements regarding in-vitro bioeffects are true EXCEPT: a. In vitro bioeffects conclusions are clinically relevant b. In vitro bioeffects are always real c. In vitro bioeffects are very important d. In vitro bioeffects may not be applicable to clinical settings

a. In vitro bioeffects conclusions are clinically relevant

The dynamic range is the ratio of the smallest to the largest __________ that a system can process without distortion. a. amplitude b. frequency c. phase delay d. spatial length

a. amplitude

When can a patient revoke consent? a. at any time b. before the procedure begins c. never d. only prior to sedation

a. at any time

When may a patient revoke their consent to be treated? a. at any time b. when it is safe to terminate the procedure c. never

a. at any time

***Which has the greatest amount of attenuation? a. bone b. fat c. water d. muscle

a. bone

A single element transducer is focused a. by the manufacturer b. cannot be focused c. by increasing power d. by the sonographer

a. by the manufacturer

To measure the US beam intensity, use a a. calibrated hydrophone b. lateral oscilloscope c. water filled phantom d. tissue equivalent phantom

a. calibrated hydrophone

Circumstances may be measured in unit of: a. cm b. cm squared c. cubic cm d. cubits

a. cm

What may be a unit of amplitude? a. cm b. Hz c. msec d. watts e. none of the above

a. cm

Put in decreasing order: A) deca B) deci C) micro D) centi

a. deca b. deci d. centi c. micro

Under which of the following conditions is lateral resolution improved? a. decreased beam diameter b. decreased pulse duration c. decreased imaging depth d. decreased pixel size e. decreased spatial pulse length

a. decreased beam diameter

Under which of the following conditions is axial resolution improved? a. decreased spatial pulse length b. decreased pulse amplitude c. decreased imaging depth d. decreased pixel size e. decreased beam diameter

a. decreased spatial pulse length

Which of the following best describes the features of a sound wave and medium that determine the speed of sound in the medium? a. density of the medium and stiffness of the medium b. density of the medium and power of the sound beam c. elasticity of the medium and frequency of the sound beam d. stiffness of the medium and elasticity of the medium e. pulse repetition period of the sound wave and density of the medium

a. density of the medium and stiffness of the medium

Which of these factors has the greatest influence on pulse repetition period? a. display depth b. thickness of the PZT crystal c. attenuation of the sound beam d. impedance of the medium e. display's dynamic range

a. display depth

If the intensity is increased increased by 3dB, it: a. doubles b. triples c. halved d. quartered

a. doubles

What is the fraction of time that a transducer is transmitting? a. duty factor b. pulse duration c. period d. PRF spatial duration

a. duty factor

What increases patient exposure? a. exam time b. frequency c. video taping d. wavelength

a. exam time

What happens to the speed of sound in a medium when the bulk modulus of the medium increases? a. faster b. slower c. unchanged

a. faster

***While scanning in a water tank, what location in a sound beam has the highest intensity? a. focal point b. focal zone c. Fresnel zone d. Fraunhofer zone e. half value depth

a. focal point

What is the location of the minimum cross- sectional area of the US beam called? a. focus b. Fraunhofer zone c. far zone d. near zone

a. focus

Which of the following does not change temporal resolution? a. frequency compounding b. persistence c. spatial compounding d. temporal resolution

a. frequency compounding

Under which circumstance is the mechanical index lowest? a. high frequency and low power b. high intensity and high frequency c. low intensity and low frequency d. low frequency and high signal amplitude

a. high frequency and low power

Which of the following will result in the greatest number of shades of gray in a digital image display? a. large pixels with many bits/pixel b. small pixels with few bits/pixel c. many TV lines per frame d. high contrast e. narrow dynamic range

a. large pixels with many bits/pixel

How is range ambiguity artifact eliminated? a. lower the PRF b. raise the PRF c. increase the gain d. use a lower frequency transducer

a. lower the PRF

Which of the following has a propagation speed closest to "soft tissue"? a. muscle b. fat c. bone d. air

a. muscle

The units of pulse repetition frequency are a. per minute b. msec c. mm/us d. MHx

a. per minute

Which of the following is associated with power mode Doppler? a. poor temporal resolution and flash artifact b. lower sensitivity and good temporal resolution c. high sensitivity and high frame rates d. flash artifact and reduced sensitivity e. good temporal resolution and flash artifact

a. poor temporal resolution and flash artifact

Impedance is the ____ of _____ and _____. a. product, propagation speed, density b. sum, stiffness, density c. quotient, stiffness, propagation speed d. difference, attenuation, density

a. product, propagation speed, density

______ resolution is determined by the spatial pulse length. a. radial b. image c. axial d. angular

a. radial or c. axial

Which of the following choices best describes an ideal epidemiologic bioeffects study? a. randomized and prospective b. benefits outweigh the risks c. retrospective and optimized d. ideal and non-biased e. prudent and safe

a. randomized and prospective

Which of the following tissues is most likely to create Rayleigh scattering? a. red blood cells b. muscle c. fat d. bone

a. red blood cells

Which of the following choices determines the signal amplitude in the transducer of an ultrasound system? a. reflected intensity of the sound beam b. post processing c. edge enhancement filtering d. persistence e. demodulation

a. reflected intensity of the sound beam

As the impedances of two media become vastly different the A) reflection increases B) transmission increases C) refraction increases D) absorption increases

a. reflection increases

Which transducer would be best to image superficial structures? a. small diameter, high frequency b. small diameter, low frequency c. large diameter, high frequency d. large diameter, low frequency

a. small diameter, high frequency

In which of these biologic tissues will sound waves propagate most quickly? a. tendon b. blood c. lung d. fat e. amniotic fluid

a. tendon

All of the following are true EXCEPT: a. Two waves with identical frequencies must interfere constructively. b. Constructive interference is associated with waves that are in-phase. c. Out-of-phase waves interference destructively d. Waves of different frequencies may exhibit both constructive and destructive interference at different times.

a. two waves with identical frequencies must interfere constructively.

Traveling through the same medium, if the frequency is doubled, the propagation speed is: a. unchanged b. doubled c. halved d. quartered

a. unchanged

Pre-processing occurs a. when the patient is scanned b. when images are transferred to the VCR c. after the images are on the tape d. when the image exits the scan converter

a. when the patient is scanned

Name 3 components of attenuation

absorption, scattering, reflection

compressions of a sound wave

areas of higher/increased pressure and density

Rarefactions of a sound wave

areas of lower/decreased pressure and density

Decimal uses a base of 10, binary uses a base of a. 1 b. 2 c. 5 d. 10

b. 2

Which of the following is not preprocessing? a. write magnification b. 3-D rendering c. fill-in interpolation d. spatial compounding

b. 3-D rendering

Depth calibration of a machine measures 100mm spaced wires to be 90mm apart. Scanning reflectors 50mm apart, what will the machine calculate the distance to be? a. 40 mm b. 45 mm c. 60 mm d. 65 mm

b. 45 mm

How many cm are 60 millimeters? a. 600 b. 6 c. 0.6 d. 0.06

b. 6

For Doppler, which incident angle results in no shift? a. 180 degrees b. 90 degrees c. 0 degrees d. 45 degrees

b. 90 degrees

*** If a 5MHz sound wave is traveling in the tissues listed below, which will have the shortest wavelength? a. Fat b. Air c. Muscle d. Bone

b. Air

The region from the transducer to the minimum beam cross-sectional area is the a. Fraunhofer zone b. Fresnel zone c. focus d. Snell's length

b. Fresnel zone

What determines the frequency of a sound beam from a pulsed transducer? a. voltage applied to the PZT b. PZT thickness c. frequency of the system d. PRF of the pulser

b. PZT thickness

Which of the following best describes a sound beam? a. electrical impulses b. a collection of mechanical vibrations in the form of compressions and rarefactions c. a wave that man can hear d. electromechanical variations e. ionic vibrations

b. a collection of mechanical vibrations in the form of compressions and rarefactions

Reject is used to a. alter the appearance of highly reflective objects b. alter the appearance of lowly reflective objects c. improve axial resolution d. improve digital scan converter sensitivity

b. alter the appearance of lowly reflective objects

Sound is traveling from medium 1 to medium 2. Propagation speeds of M1 and M2 are 1,600m/s and 1,500m/s, respectively. There is normal incidence. a. angle of incidence > angle of reflection b. angle of incidence = angle of reflection c. angle of incidence < angle of reflection

b. angle of incidence = angle of reflection

Compression is used to a. decrease the amplitude b. decrease the range of amplitudes c. decrease the range of frequencies

b. decrease the range of amplitudes

What happens to venous return to the heart during expiration? a. increased b. decreased c. unchanged

b. decreased

The Doppler shift is the _________ of two frequencies. a. sum b. difference c. product d. ratio

b. difference

If a reflector is moved twice as far away from the transducer, how will this affect the time-of-flight of a sound pulse? a. quadruple it b. double it c. no change d. halve it

b. double it

Post processing occurs when the image a. is played of the VCR b. entered the A/D converter but before display c. after it leaves the A/D converter d. after it leaves the scan converter

b. entered the A/D converter but before display

Which of the following improves the signal-to-noise ratio? a. dynamic range b. frame averaging c. gray scale d. edge enhancement e. receiver gain

b. frame averaging

If the frequency of US is increased from 0.77 MHz to 1.54 MHz, what happens to the wavelength? a. doubles b. halved c. remains d. 4 times greater

b. halved

If the frequency of an US wave is doubled, what happens to the period? a. doubles b. halved c. remains the same d. 4 times greater

b. halved

When the US machine displays only strong reflecting objects and nothing else, the sonographer should a. adjust far gain b. increase output power c. increase lateral resolution d. adjust TGC

b. increase output power

Which has the correct units? Frequency Speed Intensity Attenuation a. Hz. mm/s joules dB/ cm b. mHz m/sec W/cm2 dB c. kHz. mm/us W/cm dB/cm

b. mHz m/sec W/cm2 dB

The angle between an US pulse and the boundary between two media is 56 degrees. This is called: a. direct incidence b. oblique incidence c. indirect incidence d. orthogonal incidence

b. oblique incidence

Which of the following is not a beam steering technique for a mechanical scanhead? a. rotating wheel b. phased beam c. oscillating disc d. oscillating mirror

b. phased beam

The time from the beginning of a pulse until its end is _______? a. period b. pulse duration c. pulse length d. PRF

b. pulse duration

What happens to the speed of sound in a medium when the bulk modulus of the medium decreases? a. faster b. slower c. unchanged

b. slower

While propagating, a sound wave is refracted. Finally, it returns to the transducer. The system processes the sound wave as if it has: a. refracted and returned b. traveled in a straight line, reflected and & returned c. traveled in a straight line, attenuated, reflected and returned

b. traveled in a straight line, reflected and & returned

The speed of US in soft tissue is closest to: A. 1,540 km/sec B. 1.54 km/msec C. 1,500 m/s D. 1,540 mm/sec

c. 1,500 m/s

The duty factor for continuous wave ultrasound is a. 10.0 b. 1% c. 1.0 d. 0.0%

c. 1.0

Which has the correct order? mega-milli-kilo-micro- a. 10 6 10 -6 10 3 10-3 b. 10 -6 10 6 10 2 10 -3 c. 10 6. 10 -3 10 3 10 -6

c. 10 6. 10 -3 10 3 10 -6

Biologic effects have not been documented below what intensity (SPTA)? a. 100 W/cm b. 100 mW/m2 c. 100 mW/cm2 d. 100 mW/cm3

c. 100 mW/cm2

What is the frequency of a wave with 1msec period? a. 10,000Hz b. 1,000kHz c. 1kHz d. 1MHz

c. 1kHz

How many bits are needed to represent 16 shades of grey? a. 2 b. 3 c. 4 d. 5

c. 4

The fundamental frequency of a transducer is 2.5 MHz. What is the second harmonic frequency? a. 1.25MHz b. 4.5MHz c. 5 MHz d. 5cm

c. 5 MHz

Which of these intensities is smallest? a. SATP b. SPTP c. SATA

c. SATA

The effects of soft tissue on US are called: a. acoustic proliferation properties b. dynamic effects c. acoustic propagation properties d. biologic effects

c. acoustic propagation properties

What is not the responsibility of the sonographer? a. clean the filters b. adjust the recorder c. adjust converter matrix d. change paper

c. adjust converter matrix

Put in increasing order of propagation speed: a. air, bone, water b. bone, water, air c. air, water, bone d. water, air, bone e. bone, air, water

c. air, water, bone

An US machine has a digital scan converter but has an analog input signal. The machine needs to have a. hybrid multiplexer b. modem c. analog to digital converter d. digital monitor

c. analog to digital converter

Which of these cannot be performed by a sonographer? a. adjust overall gain b. clean VCR recording heads c. clean pixels d. adjust time gain compensation

c. clean pixels

As a result of ____ the propagation speed increases. a. increasing stiffness and increasing density b. increasing stiffness and increasing elasticity c. decreasing compressibility and decreasing density d. decreasing stiffness and decreasing density

c. decreasing compressibility and decreasing density

The Doppler shift is a measure of: a. ratio of incident frequency to reflector frequency b. sum of incident frequency and reflected frequency and reflected frequency c. difference between incident and reflected frequency d. product of incident and reflected frequencies

c. difference between incident and reflected frequency

For soft tissues, the approximate attenuation coefficient in dB/cm is equal to one-half __________ in __________. a. wavelength, mm b. frequency, Hz c. frequency, MHz d. impedance, rayls

c. frequency, MHz

If the intensity of a sound beam remains unchanged while the beam area is reduced in half, what has happened to the power? a. quadrupled b. doubled c. halved d. unchanged

c. halved

Traveling through the same medium, if the frequency is doubled, the wavelength is a. unchanged b. doubled c. halved d. quartered

c. halved

A hydrophone is used to measure a. velocity b. frequency c. intensity d. phase

c. intensity or b. frequency

Which of the following will result in the highest mechanical index? a. high frequency and low power b. high intensity and high frequency c. low frequency and high signal amplitude d. low intensity and low frequency

c. low frequency and high signal amplitude

Refraction only occurs if there are: a. normal incidence and different impedances b. indirect intensity and different propagation speeds c. oblique incidence and different propagation speeds d. oblique frequency and identical impedances

c. oblique incidence and different propagation speeds

______ is the time to complete one cycle. a. pulse duration b. pulse period c. period d. duration period

c. period

Snell's law describes physics of ____________. a. ultrasound b. reflection c. refraction d. transmission

c. refraction

If the frequency of US is increased from 0.77 MHz to 1.54 MHz, what happens to the propagation speed? a. doubles b. halved c. remains the same d. 4 times greater

c. remains the same

___________ is a redirection of US in many directions as a result of a rough boundary between two media. a. refraction b. Rayleigh scattering c. scattering d. reflection

c. scattering

Which type of artifact appears most commonly with highly reflective objects? a. reverberations b. mirroring c. shadowing d. enhancement e. defocusing

c. shadowing

Put in decreasing order of propagation speed. a. gas b. liquid c. solid

c. solid b. liquid a. solid

You are performing a quality assurance study on an ultrasound system using a tissue equivalent phantom. You make an adjustment using a knob on the system console that changes the appearance of reflector brightness from fully bright to barely visible. What are you evaluating? a. resolution b. dynamic range c. system sensitivity d. vertical calibration e. slice thickness

c. system sensitivity

The Curie Temperature has which effect? a. The backing material delaminates from the active element b. the glue binding the crystal & matching layer melts c. the ferroelectric material is depolarized d. the matching layer changes its impedance

c. the ferroelectric material is depolarized

What information does Doppler shift provide? a. flow b. cardiac output c. velocity d. speed

c. velocity

Power of sound has units of A) dB B) dB/cm C) watts D) watts/cm 2

c. watts

What are the units of intensity? a. watts b. decibles c. watts/cm squared d. decibels

c. watts/cm squared

What is the minimum value of the duty factor? a. 10.0 b. 1% c. 1.0 d. 0.0%

d. 0.0%

*** A Doppler exam is performed with a 5 MHz probe and a PRF of 15 kHz. Which of these Doppler shifts will create aliasing? a. 2 kHz b. 2.5 kHz c. 7.5 kHz d. 14 kHz

d. 14 kHz

The frequency closest to the lower limit of US is: a. 19,000kHz b. 10,000MHz c. 20,000msec d. 15,000Hz

d. 15,000Hz

The impedance of tissue is 3 x 10 to the 5th rayls and for the PZT crystal is 6 x 10 to the 6th rayls. What is the best impedance for the matching layer? a. 36 x 10 to the 6th b. 3,600 c. 10,000 d. 9.5 x 10 to the 5th e. 9 x 10 to the 4th

d. 9.5 x 10 to the 5th

The most likely amount of reflection at a boundary between soft tissues is: a. 1% b. 22% c. 34% d. 99%

d. 99%

*** If a 5 MHz sound wave is traveling in the tissues listed below, which will have the longest wavelength? a. Fat b. Air c. Muscle d. Bone

d. Bone

What is the standard for communication between medical imaging computers? a. ALARA b. PACS c. D-to- A conversion d. DICOM e. A-to- D conversion

d. DICOM

With good images on the display but not on the printer, one should a. increase the gain b. check the scan head c. check scan converter d. adjust the recorder

d. adjust the recorder

A transducer with more than one active element is called: a. multipurpose b. annular c. mechanical d. array

d. array

The units of attenuation are ______; this is a _______ scale. a. mm/cm, parametric b. dB/m, multiplicative c. none, relative d. dB, logarithmic

d. dB, logarithmic

What is the propagation speed determined by? a. wavelength b. intensity & density c. amplitude d. density and elasticity e. density and amplitude

d. density and elasticity

If the frame rate increases and the lines per frame is unchanged, what else must happen? a. US speed increases b. frequency increases c. depth increases d. depth decreases

d. depth decreases

propagation speed = _________ X wavelength a. pulse duration b. period c. number of cycles in the pulse d. frequency

d. frequency

What measures the output of a transducer? a. receiver b. display c. hydrometer d. hydrophone

d. hydrophone

The rayl is the unit of: a. intensity b. reflectance c. density d. impedance

d. impedance

Which is not an acoustic variable? a. density b. pressure c. distance d. intensity

d. intensity

What can pulsed Doppler measure that continuous wave cannot? a. duration b. speed c. velocity d. location e. frequency

d. location

Sound waves are: a. electric b. mechanical, transverse c. spectral d. longitudinal, mechanical

d. longitudinal, mechanical

Under which circumstance is cavitation most likely to occur? a. high frequency and low power b. high intensity and high frequency c. low intensity and low frequency d. low frequency and high signal amplitude

d. low frequency and high signal amplitude

In an air-tissue interface, what percentage of the US is reflected? a. 0% b. near 0% c. 50% d. near 100%

d. near 100%

With normal incidence, what factors affect refraction of US? A) propagation speeds B) frequencies C) attenuation coefficients D) none of the above

d. none of the above

The angle between an US pulse and the boundary between two media is 90 degrees. What is this called? a. direct incidence b. oblique incidence c. indirect incidence d. orthogonal incidence

d. orthogonal incidence

If a wave's amplitude is doubled, what happens to the power? a. nothing b. halved c. doubled d. quadrupled

d. quadrupled

Which of the following is determined by the source and the medium? a. frequency b. period c. propagation speed d. range resolution

d. range resolution

The dB is defined as the ____________ of two intensities. a. sum b. difference c. product d. ratio

d. ratio

What artifact has a grainy appearance and is caused by the interference effects of scattered sound? a. spackle b. reverberation c. slice thickness d. speckle e. section thickness

d. speckle

Impedance is the product of _____ and _____.

density and propagation speed

*** 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 10% of full intensity? a. -3 dB b. -50 dB c. 40 dB d. 3 dB e. -10 dB

e. -10 dB

If 300,000 cycles occur in a second, what is the wave's frequency? a. 3 MHz b. 30 kHz c. 300 MHz d. 3 kHz e. 0.3 MHz

e. 0.3 MHz

Which of the following clinical modalities has the lowest output intensity? a. pulsed Doppler b. continuous wave Doppler c. power Doppler d. duplex scanning e. gray scale imaging

e. gray scale imaging

Where does coded excitation take place? a. in the receiver b. in the tissues c. in the contrast agents d. in the matching layer e. in the pulser

e. in the pulser

In which way is an annular phase array transducer different than a linear phased array transducer? a. the linear is steered mechanically b. the linear can have multiple focal zones c. the annular can create a rectangular shaped image d. the linear has higher pulse repetition frequency e. the annular is steered mechanically

e. the annular is steered mechanically

Arrange the following from shortest to longest. A. pulse duration B. period C. pulse repetition period D. lisenting time

from shortest time to longest time: B. period A. pulse duration D. listening time C. pulse repetition period

If impedance is increased then density is what?

increased

What is the formula to calculate the wavelength?

wavelength = C/F

If frequency of sound is doubled, what happens to wavelength?

wavelength is halved