Ultrasound Physics Chapt. 1-9 Exam Questions

Front 1

True or False
When two waves reach peaks and cross the zero line at the exact same time, they are "in phase" or destructive?

Back 1

False
Constructive

Front 2

True or False
Nyquist criteria is used to determine aliasing?

Back 2

True

Front 3

True or False
Logartithms provide a powerful tool to compress data non-linearly?

Back 3

True

Front 4

True or False
The speed of sound in soft tissue is assumed to be 1540 m/sec?

Back 4

True

Front 5

Kilo is equal to?

Back 5

thousand

Front 6

Mega is equal to?

Back 6

million

Front 7

Giga is equal to?

Back 7

billion

Front 8

nano is equal to?

Back 8

billionith

Front 9

micro is equal to?

Back 9

millionith

Front 10

deci is equal to?

Back 10

tenth

Front 11

deca is equal to?

Back 11

ten

Front 12

milli is equal to?

Back 12

thousandith

Front 13

centi is equal to?

Back 13

hundredith

Front 14

hecto is equal to?

Back 14

hundred

Front 15

If two variables are directly proportional, if one increases by a factor of 5, then the other

1. decreases
2. decreases by a factor of 5
3. increases
4. increases by a factor of 5

Back 15

4. increases by a factor of 5

Front 16

If two variable are inversely proportional, if one decreased by a factor of 5, then the other
1. decreases
2. decreases by a factor of 5
3. increases
4. increased by a factor of 5

Back 16

4. increases by a factor of 5

Front 17

What is the travel time in microseconds for US to image a structure that is 5cm deep?
1. 6.5
2. 13
3. 65
4. 130

Back 17

3. 65

(13u/sec x 5cm)

Front 18

If the speed of sound in a medium is 100m/sec, how long will it take sound to travel 420m?
1. .42 sec
2. 4.2 sec
3. 42 sec
4. 420sec
5. 4200 sec

Back 18

2. 4.2 sec
(use t=d/r)
420/100=4.2 sec.

Front 19

The cosine of 90 degrees is
1. -1
2. -.5
3. 0
4. .5
5. 1

Back 19

3. 0

Front 20

Log (x/y) equals?
1. log x + log y
2. log x - log y
3. log x = log y
4. answer is not here

Back 20

2. log x - log y

(division = sub)
(mult = add)

Front 21

Unit for wavelenght

Back 21

mm

Front 22

Unit for Frequency

Back 22

hertz

Front 23

Unit for intensity

Back 23

watts/cm square

Front 24

Unit for propagational speed?

Back 24

meters/sec

Front 25

unit for period

Back 25

seconds

Front 26

Unit for power

Back 26

watts

Front 27

How is frequency and power related?

Back 27

inversely

Front 28

How is amplitude and power related?

Back 28

directly

Front 29

How is amplitude and intensity

Back 29

directly

Front 30

How is power and intensity related?

Back 30

directly

Front 31

How is wavelength and intensity related?

Back 31

unrelated

Front 32

How is acoustic velocity and density related

Back 32

Inverse

Front 33

How is stiffness and sound speed related?

Back 33

directly

Front 34

How is frequency and sound speed related?

Back 34

unrelated

Front 35

How is power and frequency related

Back 35

unrelated

Front 36

How is frequency and intensity related?

Back 36

Unrelated

Front 37

Which of the following characteristic will create the slowest speed of sound?

1. High density, high stiffness
2. low density, high stiffness
3. high density, low stiffness
4. low density, low stiffness

Back 37

3. high density, low stiffness

Front 38

What is the wavelength of a wave with an unknown frequency traveling in soft tissue?

1. 51 us
2. .51 m/s
3. .51 pascals
4. 51 watts
5. .51 mm

Back 38

5. .51 mm

(ans. is with units of length)

Front 39

What are the 4 acoustic variables?

Back 39

pressure
density
distance
temperture

Front 40

True or False
If the power of a wave is halved, the intensity is reduced to one-fourth it original value?

Back 40

False

Power is proportional to intensity

Front 41

True or False
The effects of tissue on sound waves are called bioeffects?

Back 41

False

Front 42

Chapt. 4

US pulses contain a range of freguencies called the?

Back 42

Bandwidth

Front 43

Pulsed US consists of ______ separated by______ of time

Back 43

Pulses, gaps

Front 44

Pulse repetition frequency is the _________ of pulses occurring in 1 sec.

Back 44

number

Front 45

______ is the even and odd multiples of the fundamental frequency

Back 45

harmonics

Front 46

The fraction of time that pulsed US is on is called_______?

Back 46

Duty Factor

Front 47

What is the pulse duration of a 4 cycle pulse in a period of .5 usec?

Back 47

2.0 usec.

(PD= period x # of cycles)

Front 48

If the wavelength is .5mm, the spatial pulse length for a 4 cycle pulse is____?

Back 48

2.0 mm

(SPL= wavelength x # cycles)

Front 49

The PRF is teh number of pulses that occur in a ________?

Back 49

Second

Front 50

Calculate the pulse duration for a 3.0MHz transducer in soft tissue with a 4 cycle pulse.

Back 50

1.3 usec.
(PD= period x # cycles)
1/3.0MHz = .33 x 4)

Front 51

Pulse duration will increase with all the following except?
1. period
2. number of cycles in the pulse.
3.Frequency
4. None of the above

Back 51

3. Frequency

Front 52

The duty factor will increase with all of the following except.

1. period
2. pulse duration
3. PRF
4. none of the above

Back 52

1. Period

(DF= PD/PRP)

Front 53

What is the SPL of a 4 cycle pulse with a wavelength of 0.1mm ?

1. .4mm
2. .4cm
3. 4.0 mm
4. 40.mm

Back 53

1. .4mm
(SPL= wavelength x # cycles)
.1mm x 4)

Front 54

The SPL will increase with all of the following except?
1. Number of cycles in the pulse
2. wavelength
3. frequency
4. None of the above

Back 54

3. Frequency

Front 55

If the PD is 3 u and the PRP is 35-0 usec, the DF is _____%?

1. 8.6
2. 1.16
3. .86
4. 086

Back 55

4. .086

(DF=PD/PRP)
3/350

Front 56

True or False
A range of the DF is encountered in DMS because of various conditions chosen by the instrument and the operator?

Back 56

True

Front 57

True or False
Pulsed wave ultrasound is described by the additional terms frequency, wavelength and propagational speed?

Back 57

False

Front 58

True or False

DF is unitless?

Back 58

True

Front 59

True or False

SPL is determined by the length of the pulse and the propagation speed.

Back 59

False

Front 60

True or False

The shorter the pulse, the broader the bandwidth?

Back 60

True

Larger pulse = narrow bandwidth

Front 61

True or False

With standard US pulses, the frequency of the US changes significantly as the wave opopagates throught the body?

Back 61

False

Front 62

What is the PD equal to?

1. frequency x period
2. period x wavelength
3. # of cycles in a pulse/wavelength
4. period x # of cycles in the pulse

Back 62

4. Period x # cycles in the pulse

Front 63

In order to image deeper structures, _______.

1. the TGC needs to be increased.
2. the PRF needs to be increased.
3. the frame rate needs to be increased
4. the PRF needs to be decreased.

Back 63

4. The PRF needs to be decreased.

Front 64

The PRF is the number of _______sent to the transducer each second.

1. none of the answers
2. cycles
3. ultrasound pulses
4. voltage pulses

Back 64

4. voltage pulses

Front 65

Which resolution depends on penetration depth, lines per frame, and the number of focuses.

1. Temporal
2. Contrast
3. Detail
4. Axial

Back 65

1. Temporal

Front 66

To receive information for display at a rapid rate, it is desirable to use a _______.

1. high operating frequency
2. lower operating frequency
3. Low PRF
4. high PRF

Back 66

4. High PRF

Front 67

What is the maximum depth in soft tissue for a PRF of 10kHz.

1. 7.5 mm
2. 7.7 mm
3. 7.7 cm
4. 7.5 cm

Back 67

1. 7.5 mm
PRP= imaging depth x 13 usec. PRF=1/PRP.
1/10kHz

Front 68

What is the maximum penetration depth with a frame rate of 32 frames per second and a line density of 100 lines per fram and using only one focus.

1. 24 mm
2. 12 cm
3. 20 cm
4. 24 cm

Back 68

4. 24 cm.

FR = 77,000/3200 = 24

Front 69

The PRF is ________ Hz if ther are 30 fram per secon and 40 lines per frame.

1. 12,000
2. 1200
3. 12
4. 120

Back 69

2. 1200

(30 x 40) = 1200

Front 70

The _______ is the number of sonographic images entered into memory per second.

1. cine loop
2. frame rate
3. image refresh rate
4. PRF

Back 70

1. Cine loop

Front 71

True or False
If the penetration is increased the PRF must be increased

Back 71

False

Front 72

the range of frequencies found within a pulse describes with of the following terms?

1. pulse repetition frequency
2. harmonics
3. bandwidth
4. duty factor
5. compression

Back 72

3. bandwidith

Front 73

True or False

The DF is an indicator of mechanical bioeffects?

Back 73

True

Front 74

True or False

The SPL is equal to the frequency multiplied by the number of cycles in the pulse

Back 74

False

Front 75

If the maximum imaging depth is 10 cm, adn ther are 128 lines per frame, how much time does it take to shoot one frame?

Back 75

16.64 msec/frame

Front 76

if the maximum imaging depth is 10 cm and there are 4 packets per line and 128 lines how long does it take to shoot a color frame?

Back 76

66.56 msec/frame

10x4x128x13

Front 77

If a pulse has a duration of 4 msec and a PRP is 10msec, what is the DF?

Back 77

40%

Front 78

Which of the following will NOT result in a shorter pulse duration?

1. using a higher frequency
2. using a shorter period
3. a lower propagaion velocity
4. suing few pulses.

Back 78

3. a lower propagation velocity

Front 79

True or False
A non scanned modality implies that over time the acoustic beams are repeatedly transmitted in the same direction

Back 79

True

Front 80

How many gray levels can be represented by 10 bits?

Back 80

1024

2 to 10 power.

Front 81

Multiple transmit foci beams have the advantage of _______ and the disadvantage of ____________.

Back 81

Narrower display beam, lower frame rate.

Front 82

Limiting dynamic range through suppression of smaller, weaker signals is called?

Back 82

rejection

Front 83

What type of resolution includes axial, lateral, and elevation resolution?

Back 83

Detail

Front 84

Contrast resolution is determined by teh ____________ and the number of bit per pixel in the display.

Back 84

Scan Converter

Front 85

Which of the following approaches would yield the best imaging results on a large, difficult to image patient?

1. 6MHz transmit and recieive,.8 cm aperture
2. 1.4 MHz transmit, 2.8 Mhz receive, 1 cm aperture
3. 2MHz transmit, 4MHz receive, 1.8 cm aperture
4. 2.5 MHz transmit and receive and 2, cm aperture

Back 85

4. 2. 5 MHz transmit and receive and 2 cm aperture.

Front 86

The display form the present the depth in the vertical axis and the amplitude of the echo in the horizontal axis is called?

Back 86

A Mode

Front 87

Television monitors present images at a rate of _______?

Back 87

30 per second

Front 88

Analog to digital converters convert ______ voltage representing echoes to ________ for digital signal processing and storage.

Back 88

Analog, numbers

Front 89

The ___________ is where the action orginates.

Back 89

Beam former

Front 90

After echo data are scan converted into image format and preprocessed, the 2D image frames are ____________.

Back 90

stored in image memory.

Front 91

With too much gain, __________.
1. saturation occurs
2. differenced in echo strenghth are lost
3. there is a decrease in contrast resolution.
4. All of the above

Back 91

All of the above

Front 92

Typically TGC amplifiers compensate for about ____________ of attenuation?

Back 92

60 dB

Front 93

Holding and displaying one from out of the sequence is known as:____________

Back 93

Freeze Frame

Front 94

To receive information for display at a rapid rate, it is desireaable to use a ________

Back 94

High PRF

Front 95

The scan coverter___________

Back 95

Reformats echos data into image form for image processing, storage and display.

Front 96

What is the term used to describe the picture elements?

Back 96

Pixel

Front 97

Brightness mode is term?
1. gray-scale
2. B-Mode
3. B-Scan
4. All of the above

Back 97

4. All of the above

Front 98

Persistence does all of the following except:
1. increase contrast resolution
2. Increase frame rate
3. improve dynamic range
4. decrease speckle

Back 98

2. Increase dynamic range.

Front 99

PACS stands for:

Back 99

Picture, archiving and communications system

Front 100

The functions of a beam former aer all of the following except:
1. compress the dynamic range
2. direct, focus, and apodize the transmitted beam.
3. determine the PRF
4. compensate for attenuation

Back 100

1. Compress the dynamic range.

Front 101

All of the following are advantages of spatial compounding except:
1. echo information is added from previous frames
2. specular surfaces are presented more completely.
3. speckle reduction
4. surfaces are interogated at more than one angle.

Back 101

1. echo imformation is added from previous frames.

Front 102

_________ determines how echo data stored in memory will appear on the display.

Back 102

Postprocessing

Front 103

The ability of a gray scale display to distinguish between echoes of slightly different intensities is called?

Back 103

Contrast resolution

Front 104

The ratio of teh largest to the smallest amplitude that a system can handle is called:

Back 104

dynamic range

Front 105

The ______________ is responsible for electronic beam scanning, steering, focusing, apodization, and aperature functions with arrays.

Back 105

Beam former

Front 106

To avoid echo misplacement:
1. a code is added to the pulser
2. multiple receivers are installed.
3. all echoes from one pulse must be received before the next pulse is emitted.

Back 106

All echoes from one pulse must be received before the next pulse is emitted.

Front 107

Contrast resolution depends on:

Back 107

number of bits per pixel.

Front 108

The __________ is the number of sonographic images entered into memory per second.

Back 108

Frame rate

Front 109

Normally the number of channels does not exceed the number of _________?

Back 109

elements in the transducer.

Front 110

Television monitors produced __________ images per second.

Back 110

30

Front 111

How many horizontal lines are used to produced a picture on a television monitor?

Back 111

525

Front 112

The dynamic range of an ultrasound system is:

Back 112

The ratio of the maximum amplitude to the minimum echo strength that can be displayed.

Front 113

In real-time scanning, the PRF depends on the number of _______ per frame, and the ________ rate.

Back 113

lines, frame

Front 114

Which of the following forms of resolution improved when frame rate increases?
1. temporal
2. lateral
3. longitudinal
4. spatial

Back 114

1. temporal

Front 115

A sonographer adjusts an ultrasound scan to double the depth of view from 5 cm to 10 cm. What happens to the frame rate?
1. it is doubled
2. it is halved
3. it is unchanged

Back 115

2. it is halved

Front 116

A sonographer adjusts an ultrasound scan to double the depth of view from 5 cm to 10 cm. If the frame rate remains the same, which one of the following also occurs?
1. increased the line density.
2. narrower sector
3.mulit focused imaging turned on.
4. wider sector

Back 116

2. Narrower sector

Front 117

A sonographer using a phased array ultrasound system, turns off the multi-focus feature. What is most likely consequence of this action?
1. temporal resolution improves
2. frame rate decreases
3. temporal resolution degrades
4. imaging depth increases

Back 117

1. temporal resolution improves.

Front 118

Which of the following is the most important in determining the frame rate of the system?
1. transmitter output
2. tranducer frequency
3. speed of sound in the medium
4. dynamic range of the received

Back 118

dynamic range of the receiver

Front 119

The acoustic power of a sound beam emitted from a transducer is determined by the _____________ of the pulser's signal.

Back 119

Voltage

Front 120

Place in order the ultrasound system functions

Back 120

amplification, compensation, compression, demodulation, reject.

Front 121

Which electronic component is require for grayscale imaging?

Back 121

scan converter

Front 122

All of the following are disadvantages of analog scan converter except:
1. image fade
2. image flicker
3. deterioration
4. Low resolution image

Back 122

4. low resolution image

Front 123

All of the following are advantages of PACS systems except:
1. older, archieve studies and reports an be reviewed easliy
2. images have hight resolution than what appears on the systems display.
3. data will not deteriorate
4. images can be delivered to distant location on the imaging netork.

Back 123

2. images have higher resolution than that what appears on the systems display.

Front 124

All of the following are true about a wide dynamic range except:
1. perferred for imaging abdominal organs.
2. low contrast
3. high contrast
4. many shades of gray

Back 124

3. High contrast

Front 125

Which of the following are averaging techniques of an ultrasound system?
1. parallel processing
2. pixel interpolation
3. smoothing
4. persistence

Back 125

persistence

Front 126

Changing the radio frequency signal into a video signal is known as______?

Back 126

demodulation

Front 127

When the signal to noise ratio is low, the signal is __________ than the noise, therefore the image quality is __________?
1. higher, better
2. lower, better
3, higher, worse
4. lower, worse

Back 127

4. Lower, worse

Front 128

What are the two key issues concerning US data?
1. storage and displaying
2. receiving and storage
3. storage and compression
4. compression and displaying

Back 128

4. Storage and compression.

Front 129

The shadowing and enhancement are description of __________ artifacts?
1. attenuation
2. refraction
3. propagation
4.reverberation

Back 129

1. attenuation

Front 130

Which of the following is not a form of reverberation?
1. comet-tail
2. mirrior image
3. ring-down
4. speckle

Back 130

Speckle

Front 131

Which artifact displaces structures axially?

1. Refraction
2. Speed Error
3. Reverberation
4. Grating lobes

Back 131

Speed Error

Front 132

Mirror image artifact is a form of:
1. reverberation
2. Grating Lobes
3. speed error
4. refraction

Back 132

1. reverberation

Front 133

Weakening of echoes distal to a strongly attenuation structure describes ________.

Back 133

2. Shadowing

Front 134

Aliasing is the appearacne of Doppler information on the ________ of the baseline.

Back 134

Wrong side

Front 135

Axial resolution is determined by ________ and lateral resolution is determined by _______.

Back 135

SPL and beam width

Front 136

Mirror image is ocmmonly seen around which structure?

Back 136

Diaphragm

Front 137

Enhancement of an echo results from a structure having ______.

1. higher attenuation than surrounding structures
2. higher impedance than surrounding structures
3. lower density than surrounding structures
4. lower attenuation than structures.

Back 137

4. lower attenuation than surrounding structures

Front 138

Ring-down artifact is a form of _______.

Back 138

Reverberation

Front 139

How are axial and lateral resolutions artifactual?
1. Two adjacent structures seen as one.
2. increase from actual size of structure.
3. Failura to resolve a mass due to loss of detail.
4. All of the above

Back 139

4. All of the above.

Front 140

Which of the following is not an image artifact?
1. Incorrect respresentation of motion in color.
2. Anything not properly indicative of teh structures imaged.
3. Errors in presentation of anatomic structures.
4. None of the above.

Back 140

4. None of the above.

Front 141

Gray-scale artifacts include all of teh following except:
1. mirror image
2. aliasing
3. range ambiguity
4. shadowing

Back 141

2. aliasing

Front 142

The most common artifact encounter in Doppler US is ________.
1. clutter
2, range ambiguity
3. aliasing
4. mirror image.

Back 142

3. Aliasing

Front 143

Additional beams emitted from an array transducer produces what time of artifact?

Back 143

duplicate structures laterallyy

Front 144

Which of the following would likely demonstrate acoustic enhancement?
1. Solid mass
2. gallstone
3.. gallbladder
4. complex mass

Back 144

3. gallbladder

Front 145

Aliasing does not occur in _________.

Back 145

Continuous Wave Doppler

Front 146

Beneficial artifacts include all of the following except:
1. reverberation
2. Enchancement
3. shadowing

Back 146

1. reverberation

Front 147

Which artifact duplicates a structure on the opposite side of a strong reflector?

Back 147

Mirror image

Front 148

Refraction may display ______
1 incorrect structure shape.
2. incorrect structure size.
3. incorrect structure location
4. all of the above

Back 148

4. all of the above.

Front 149

A change in sound direction from on medium into another is known as __________.

Back 149

refraction

Front 150

Equally spaced relections with decrease in amplitude with depth describes _______.

Back 150

Reverberation

Front 151

Which of the following would be least likely to cause acoutic shadowing?
1. Urinary bladder
2. uterine fibroid
3. gallstone
4. bowel gas

Back 151

1. Urinary Bladder

Front 152

Mirror imaging of a Doppler spectrum can ________.

1. appear on teh oposite side of the baseline.
2. Occur when the Doppler angle is near 90 degrees.
3. occur when the receiver gain is set too high.
4. all of the above

Back 152

4. all of the above.

Front 153

The assumptions in teh design of sonographic instruments include all of the following except?
1. amplitude and intensity are properties of the structure
2. sound travels in a straight line.
3. echoes originate from objects located on teh beam axis.
4. sound travels at different speeds in soft tissues.

Back 153

4. sound travels at different speeds in soft tissue.

Front 154

Range ambiguity can occur in which of the following?
1. Pulsed Doppler instruments
2. Color doppler instruments
3. Duplex instruments
4. All of the above

Back 154

4. All of the above

Front 155

True or False
Artifacts can help or hinder proper interpretation and diagnosis

Back 155

True

Front 156

True or False
Grating lobes are esential for the proper operation of a linear phased array transducer.

Back 156

False

Front 157

True or False
Enhancement weakens the amplitued of structures idstally.

Back 157

False

Front 158

True or False
Some artifacts are produce by improper equipment settings.

Back 158

True

Front 159

True or False
External influences can also produced artifiacts.

Back 159

True

Front 160

Temporal average is almost always smaller than the pulse average, when is this not the case?

Back 160

CW Doppler because the pulse is always on.

Front 161

What of kind of measurement does the 1st letter of the 2nd cluster letter refer to?

Back 161

Intensity measurement over time.

Front 162

What is pulse average

Back 162

a measurement of the power in the pulse by the PD time.

Front 163

What is a hydrophone

Back 163

A specialized transducer to measure acoustic pressure fields

Front 164

Beam uniformity factor?

Back 164

Measure of how uniform beam is uniformily.

Front 165

Hydrophone parameters of importance?

Back 165

Bandwidth, sensitivity, directivity and flatness response.

Front 166

What is the hydrophone analysis used for?

Back 166

Safety, quality assureance and the results used in the design process.

Front 167

What is BUF always greater than or equal to and what would perfectly uniform beam have and BUF equal to?

Back 167

BUF is always greater or equal to 1
1= perfectly uniform.

Front 168

2 types of hydrophone?

Back 168

Needle and membrane

Front 169

What are thermal indices?

Back 169

A predictive value which estimates the Max Temp. rise expected for current situation.

Front 170

What present the greatest potential for mechancial bioeffects?

Back 170

2D

Front 171

Mechanical Index

Back 171

MI = Peak rerarefraction pressure / sq. root. operating frequency.

Front 172

What present the greatest potential for mechancial bioeffects?

Back 172

2D

Front 173

What does an increase in mechancial index indicated?

Back 173

More likely to cause cavitation.

Front 174

Mechanical Index

Back 174

MI = Peak rerarefraction pressure / sq. root. operating frequency.

Front 175

3 thermal indices:

Back 175

TIS = Soft tissue
TIB = Bone
TIC= cranial bone

Front 176

What does an increase in mechancial index indicated?

Back 176

More likely to cause cavitation.

Front 177

ALARA

Back 177

As Low As reasonably achievable.

Front 178

3 thermal indices:

Back 178

TIS = Soft tissue
TIB = Bone
TIC= cranial bone

Front 179

ALARA

Back 179

As Low As reasonably achievable.

Front 180

What are the 2 principal components to exposure.

Back 180

Intensity and scan time duration.

Front 181

What are the 2 principal components to exposure.

Back 181

Intensity and scan time duration.

Front 182

What is In vivo?

Back 182

testing within the body

Front 183

What is in vitro?

Back 183

testing outside the body

Front 184

Threshold effect

Back 184

implies that there is a limited or boundry above which a specific outcome is achieved and below a different outcome is achieved.

Front 185

Threshhold

Back 185

A limited or boundry

Front 186

What does the bubble collapse of cavitation cause

Back 186

Increase amplitude shockwaves and extremely increased tempeture.
and localized cellular death around implosion

Front 187

What is the principal for mechancial bioeffects

Back 187

cavitation

Front 188

What is the peak rerarfractional pressure related to?

Back 188

the likelihood of implosion.

Front 189

What happens to unstable cavitation?

Back 189

-results in implosion mircrobubbles
-can completely fragment or lead to a colelction of smaller microbubbles.

Front 190

What can happen if micro streaming flow get to strong?

Back 190

It can cause cellular harm.

Front 191

What is microstreaming?

Back 191

When fluids surrounds the bubbles begin to flow because of bubble vibration.

Front 192

Stable cavitation?

Back 192

Occurs when ocillation of teh microbubbles does not lead to collapse

Front 193

What are 2 types of cavitation?

Back 193

Stable
Transient (Unstable)

Front 194

How are thermal bioefftects caused?

Back 194

-heat absorption
-for each 10 degrees C increased there is a doubling in enzymatic activity.

Front 195

Two mechanisims for creating bioeffects?

Back 195

Thermal and Mechanical

Front 196

When is TA and TP measurement taken?

Back 196

PRP

Front 197

Pulse Average Formula?

Back 197

PA= energy (power)/PD

Front 198

What does spatial mean?

Back 198

How a beam is distributed over space.

Front 199

What should the ISPTA never exceed?

Back 199

720mW/cm squared

Front 200

What is the pulse Schliern System?

Back 200

-Uses an intense focused light source to illunimate a transparent medium.
-Used for beam assesment & power measurment.

Front 201

True or False
A peak is always greater than or equal to the average

Back 201

True

Front 202

True or False
Temporal average is almost always small than the pulse average.

Back 202

True

Front 203

Beam uniformity factor formula

Back 203

BUF = SP/SA

Front 204

What are thermal bioeffects dependent on

Back 204

-time exposure
-Increased intensities above 40 degree C.

Front 205

What is the best indicator of thermal bioeffects?

Back 205

SPTA

Front 206

What is the best indicator for mechanical bioeffects?

Back 206

SPPA

Front 207

What hold the smallest inetnisty both spatially and temporally.

Back 207

SATA

Front 208

What hold the greatest intensity both spatially & temporaly?

Back 208

SPTP
SPTP>SPPA

Front 209

Duty Factor equals

Back 209

TA/PA

Front 210

What are the common ISPTA values below?

Back 210

720mW/cm sq.

Front 211

How do you convert a pulse average to temporal average.

Back 211

PA x DF=TA

Front 212

How do you convert the temporal average to the pulse average?

Back 212

PA= TA/DF

Front 213

How do you convert SA to SP?

Back 213

SA x BUF = SP

Front 214

What are common ISPPA values below?

Back 214

190 w/cm sq.

Front 215

Name an example of a threshhold effect?

Back 215

Inertial cavitation

Front 216

What are mechanical bioeffects related to:

Back 216

Short terms events.

Front 217

Issues as to why findings towards ultrasound guidelines are incomplete?

Back 217

-in vitro isn't complex as human tissue.
-Different patients habitus.
-Can't test on human tissue
-Latency period.
-Affects could be caused by many different things.
-built in bias with already sick patients.

Front 218

AIUM is?

Back 218

American Institute of Ultrasound in Medicine.

Front 219

What is the pulse average

Back 219

A measure of the power in the pulse divided by the PD time.

Front 220

Diagnostic Ultrasound transducer generate a ______ of sound into the body?
1. Pulse
2. wave
3. frequency
4. Doppler

Back 220

1. pulse

Front 221

A rectangular image display would be seen when using a ________ transducer?

1. convex
2. sector
3. linear
4. vector

Back 221

3. linear

Front 222

The location of each dot corresponds to the _______ of the echo to return.
1. strength
2. pulse
3. time
4. frequency

Back 222

3. time

Front 223

The ________ format determines the starting points and paths for the individual scan.
1. location
2. display
3. scan
4. image

Back 223

3. scan

Front 224

Vertical parallel scan lines are seen with which transducer format?
1. Curvilinear
2. linear
3. vector
4. convex

Back 224

2. Linear

Front 225

A _______ scan is shaped like a slice of pie?
1. convex
2. curivilinear
3. sector
4. linear

Back 225

3. sector

Front 226

Sonography is medicla anatomic imaging using a ______-______ technique.

1. transducer instrument
2. starting point
3.vertical parallel
4. pulse echo

Back 226

4. pulse echo

Front 227

3D imaging requires many adjacent tissue ____ ____ to build the image.

1. frequency shifts
2. ultrasound pulses
3. moving objects
4. cross sections

Back 227

4. cross sections

Front 228

True or False
One pulse of ultrasound generates a single scan line as it travels through tissue.

Back 228

True

Front 229

True or False
Pulsed ultrasound transducers can only generate ultrasound pulses.

Back 229

False

Front 230

______ is the number of complete cycles per second.

1. period
2. propagation speed
3. wavelength
4. Frequency

Back 230

4. Frequency

Front 231

Sound requires a ________ through which to travel.
1. wave
2. pressure
3. vacuum
4. medium

Back 231

4. medium

Front 232

Stiffer media have ______ sound speeds.

1. stiffness doesn't change the propagation speed.
2. lower
3. higher
4. sound cannot propagate through stiffer media.

Back 232

3. higher.

Front 233

Propagations speed is primaritly determined by the _____ of the medium.
1. thickness
2. stiffness
3. density
4. water

Back 233

2. stiffness

Front 234

Ultrasound pulses contain a range of frequencies called the _______.

1. fundamental frequencies
2. duty factor
3. bandwidth
4. pulse repetition frequenc.

Back 234

3. bandwidth

Front 235

Regions of lower pressure and density are called

1. compressions
2. longitudinal waves
3. rarefactions
4. acoustic variables.

Back 235

3. rarefactions

Front 236

Period is the _____ it takes for one _____ to occur.
1. time; wavelength
2. frequency; cycle
3. time; pulse
4. time; cycle

Back 236

4. time; cycle

Front 237

_______ is the even and odd multiples of the fundamental frequency.

1. bandwidth
2. mechancial waves
3. harmonics
4. side lobes

Back 237

3. Harmonics

Front 238

Propagation speed is higher in _____ than soft tissue.
1. bone
2. lung
3. fat
4. water

Back 238

1. Bone

Front 239

The fraction of time that pulsed US is on is called____?
1. PRP
2. DF
3. Period
4. SPL

Back 239

2. DF

Front 240

As sound travels, the reduction in amplituded and intensity of the wave is called?
1. attenuation
2. absorption
3. reflection
4. scattering

Back 240

1. attenuation

Front 241

The wavelenght of 3 MHz US in soft tissue is ______ mm.
1. 0.51
2. 5.1
3. 510
4. 4.6

Back 241

1. 0.51

Front 242

If the wavelength is .5 mm the spatial pulse length for a 4 cycle pulse is:
1. 2.0mm
2. .8mm
3. 8.0mm
4. .2mm

Back 242

1. 2.0mm

SPL= wavelength x # of cycles

Front 243

If you employ a 7.5 MHz transducer, what is the wavelength of the sound in soft tissue.
1. 1.1mm
2. .11mm
3. 025mm
4. .20mm

Back 243

4. .20mm

wavelength = c/f

Front 244

20 kHz is equal to _____ Hz.
1. 200,000
2.2000
3. 200
4. 20,000

Back 244

4. 20,000

Front 245

What is the attenuation coefficient for a 5.0 MHz transducer in soft tissue?
1. 10.0 dB/cm
2. .1 dB/cm
3. 2.5 dB/cm
4. .25dB/cm

Back 245

2. 2.5dB/cm

attn. coeff. = 1/2 frequency.

Front 246

The attenuation of a 5.0 MHz transducer at a depth of 4cm is _____dB.
1. 1.6 dB
2. 10 dB
3. 20 dB
4. 16. dB`

Back 246

2. 10. dB

1/2 freq. x imaging depth

Front 247

If the beam power increases, intensity will _______.
1. remain unchanged.
2. double
3. increase
4. decrease

Back 247

3. increase

power directly porportional to intensity

Front 248

Attenuation increases with increasing ______.
1. pressure
2. frequency
3. power
4. wavelength

Back 248

2. frequency

Front 249

For perpendicular incidence, the incidence angle is ______ degrees.

Back 249

0 degrees

Front 250

The PRF is the number of pulses that occur in a _______.

Back 250

Second.

Front 251

Calculate the pulse duration for a 3. MHz transducer in soft tissue with a 4 cycle pulse.
1. 1.2 micro second
2. 12. micro second
3. 13. micro second
4. 1.3 micro second

Back 251

4. 1.3 micro seconds

PD = P x # cycles

Front 252

CW Doppler has a DF of _____%

Back 252

100%

Front 253

Impedance is equal to density multiplied by ____
1. wavelength
2. path length
3. stiffness
4. propagational speed

Back 253

4. propagational speed

Front 254

Snell's law relates the _____ beam direction to the incident beam direction and the speeds of sound in the two materials forming the interface?
1. transmitted
2. rarefaction
3. Scattering
4. reflected

Back 254

1. transmitted

Front 255

What does 3 dB of attenuation mean?

1. one third of the original intensity.
2. one half of the original intensity?
3. increasing amplitude
4 decibels more than the original intensity.

Back 255

2. one half of the original intensity.

Front 256

The attenuation of a 5 MHz tranducer in soft tissue would be _____ dB in 2 cm of depth.

1. 20.
2. 10.
3. 5.
4. 1.25

Back 256

3. 5.

1/2 freq. x imaging depth

Front 257

The distance to a reflector in soft tissue is 15 cm. What is th round trip time to this depth?
1. 11.5 micro second
2. 19.5 micro second
3. 195. micro second
4. 1.15 micro second

Back 257

3. 195 micro second

RT - 13 x 15

Front 258

In oblique incidence the ____ and ____ angles are always equal.
1. normal ; transmitted
2. incidence; transmitted
3. incidence; reflection
4. transmitted; reflected

Back 258

3. Incidence; reflection

Front 259

If an echo returns 104u after a pulse was emitted by a transducer, at what depth is the structure that produced the echo located?
1.8mm
2. 8.mm
3. 80.cm
4. 8.cm

Back 259

4. 8.cm

104 / 13

Front 260

Intensity is equal to the power of a wave dived by the _____ over which the power is spread.
1. area
2. diameter
3. radius
4. width

Back 260

1. area

Intensity = power/beam area

Front 261

Amplitude is the maximum variation that occurs in an acoustic ______.
1. variable
2. propagation speed.
3. Wave
4. medium

Back 261

1. Variable

Front 262

____ is the dominant factor contributing to attenuation of ultrasound in soft tissue.

Back 262

Absorption

Front 263

If teh density of medium 2 is 10% greater than that of medium 1 and the propagation sppeds are equal, the impedance of medium 2 is _____ than medium 1.

Back 263

20%

Front 264

True or False
Interfaces that scatter ultrasound energy are usually considered to be those that are equal to or smaller than the wavelength.

Back 264

True

Front 265

True or False
Spaltial pulse length is determined by the length of teh pulse and the propagation speed

Back 265

False

Front 266

True or False
The shorter the pulse, the broader teh bandwidth

Back 266

True

Front 267

Select the sequence that appears in increasing order.
1. milli, hecto, centi, deci, nano, giga.
2. centi, deci, deca, hecto
3. namo, milli, micro, deci, deca, mega
4. mega, kilo, hecto, milli, giga

Back 267

2.

Front 268

The direction of motion of a particle in a wave is perpendicular to the direction of propagation of teh wave. What type of wave is this?

Back 268

Transverse

Front 269

Waves that exist at the same location and time will combine together. What is this called?
1. rarefaction
2. interference
3. inference
4. mechanical interaction

Back 269

2. interference

Front 270

What term describes the number of cycles that an acoustic variable completes in a second?
1. period
2. frequency
3. variable rate
4. PRP

Back 270

2. frequency

Front 271

If the power in an US beam is unchanged. While at the same time, the beam area doubles, then the beam's intensity.

Back 271

Halved.

i=p/area

Front 272

A _____ impedance of the transducer element allows more energy to transmit into the patient.
1. faster
2. slower
3. lower
4. higher

Back 272

3. lower

Front 273

At a distance of two near zone lengths, the beam diameter is ______ the transducer diameter.

Back 273

equal to

Front 274

Without matching the transducer has an impedance of _______ times that of the tissue.

Back 274

20

Front 275

Another name for fresnel zone is_____

Back 275

near zone

Front 276

The matching layer______.

Back 276

reduces the reflection of ultrasound at the element.

Front 277

What principle states that some materials produce a voltage when deformed by and applied pressure?

Back 277

Piezoelelectric Principle

Front 278

Electric ______ applied to a transducer are covertered to US.

Back 278

Voltages

Front 279

Sequenced, phased, and vector are types of:
1. operations
2. transducers
3. constructions
4. focusing

Back 279

1. Operations

Front 280

Which resolution relates to more directly to transducers?
1. temporal
2. Vectoral
3. contrast
4. detail

Back 280

4. detail

Front 281

US transducers operate according to ________.

Back 281

Piezoelectric principle

Front 282

What image format is similar to that for convex array except that the transducer contace surface is smaller?

Back 282

Vector Image

Front 283

Linear and convex are types of:

Back 283

Scanning

Front 284

Three aspects of imaging resolutions are contrast, temporal and _______.

Back 284

Detail

Front 285

Without being matched, the ultrasound transducer would cause ______ of the energy to be reflected at the skin border.

Back 285

80%

Front 286

Electronic scanning is performed by _____.
1. mechanical transducers
2. array transducers
3. sector transducers
4. linear transducers

Back 286

2. array transducers

Front 287

_____ array is the combination of linear and phased array operations.
1. phased
2. convex
3. vector
4. interventional

Back 287

3. Vector

Front 288

The impedance of the matching layer is _______.
1. less than the value between the transducer element and tissue.
2. equal to the tissue.
3. greater than the value between the transducer element and tissue.
4. intermediate value between the transducer element and tissue.

Back 288

1. less than the value between the transducer element and tissue.

Front 289

True or False
Optimum apodization changes continually with focusing and steering.

Back 289

True

Front 290

True or False
Lateral resolution consistent at any depth.

Back 290

False

Front 291

True or False
The focal zone is the length of teh focal region.

Back 291

True

Front 292

True or False
Intensity variations are greatest in the far zone.

Back 292

False

Front 293

True or False
Many frequencies are present in short pulses.

Back 293

True

Front 294

True or False
As sound travels, the width of the beam remains unchanged due to focusing.

Back 294

False

Front 295

True or False
Even unfocused transducer have a natural focus.

Back 295

True

Front 296

True or False
Elevational resolution can be considered a third aspect of detail resolution.

Back 296

True

Front 297

True or False
Contrast and temporal resolutions relate more directly to the transducer.

Back 297

False

Front 298

True or False
Snell's law can be applied to the surface of a transducer to determine the beam profile of the wave that emanates from the surface.

Back 298

False

Front 299

True or False
Cermanics used as materials in the production of modern US transducer element are naturally piezoelectric.

Back 299

False

Front 300

In order to image deep structures __________.
1. the TGC needs to be increased
2. the PRF needs to be decreased.
3. the frame rate needs to be increased.
4. the PRF needs to be increased.

Back 300

2. the PRF needs to be decreased.

Front 301

a bit memory has an _______ shade memory.
1. 4
2. 8
3. 256
4. 16

Back 301

4. 16

Front 302

Which resolution depends on penetration depth, lines per frame and the number of focuses?
1. axial
2. temporal
3. contrast
4. detail

Back 302

2. temporal

Front 303

To receive information for display at a rapid rate, it is desirable to use a _______.
1. high operating frequency.
2. low PRF
3. lower operating frequency
4. high PRF

Back 303

4. high PRF

Front 304

Old echo information from previous frames is retained while the new echoes are added to the image in the direction in which the scan plane is moving is called______.
1. spatial compounding
2. pixel interpolation
3. panoramic imaging
4. harmonic imaging

Back 304

3. panoramic imaging

Front 305

The frequency of the ______ determines the frequency of the resulting ultrasound pulse.
1. voltage pulse
2. bandwidth
3. beam former
4. operating frequency

Back 305

1. voltage pulse

Front 306

What is the maximum depth of soft tissue for a PRF of 10kHz?

Back 306

7.7cm

PRP x ID x 13usec.
PRF 1/PRP = 1/10kHz

Front 307

If the PRF of a real time system is 2200 Hz, the maximum depth of imaging would be ________.
1. 35cm
2. 30 mm
3. 30cm
4. 35mm

Back 307

4. 35mm

PRP= ID x 13usec.
PRF = 1/PRP

Front 308

The PRF is _______ Hz if there are 30 frames per second dn 40 lines per frame.

Back 308

1200

30 x 40 = 1200

Front 309

True or False
There are both transmission and reception channels.

Back 309

True

Front 310

True or False
If the penetration is increased the PRF must be increased.

Back 310

False

Front 311

____ is the number of complete cycles per second.
1. Period
2. Wavelength
3. Frequency
4. Propagation speed

Back 311

3. Frequency

Front 312

The following are all ultrasound frequencies except:
1. 30,000 Hz
2. 250.0kHz
3. 15.0 kHz
4. .30 Hz.

Back 312

3. 15.0 kHz

Front 313

If Frequency increases, period will _____.
1. increase
2. None of the above
3. decrease
4. remain unchanged

Back 313

3. decreased

Front 314

Stiffer media have _____ sound speeds.
1. Stiffness doesn't change the the propagation speed.
2. sound cannot propagate through stiffer media.
3. higher
4. lower

Back 314

3. higher

Front 315

Frequency _____ wavelength.
1. is equal to
2. has no bearing on
3. is inversely proportional to
4. is directly proportional to

Back 315

3. is inversely proportional to

Front 316

Propagation speed is primarily determined by the _____ of the medium.
1. stiffness
2. density
3. thickness
4. water

Back 316

1. stiffness

Front 317

Ultrasound pulses contain a range of frequencies called the ______.
1. bandwidth
2. duty factor
3. fundamental frequencies
4. pulse repetition frequencies

Back 317

1. bandwidth

Front 318

Pulse repetition frequency is the ____ of pulses occuring in 1 second.
1. speed
2. number
3. type
4. cycle

Back 318

2. number

Front 319

Regions of lower pressure and density are called _____.
1. longitudinal waves
2. compressions
3. acoustic variables
4. rarefactions.

Back 319

4. rarefactions

Front 320

_____ is (are) the even and odd multiples of the fundamental frequency.
1. side lobes
2. Harmonics
3. mechancial waves
4. bandwidth

Back 320

2. Harmonics

Front 321

The rate at which energy passes through a unit area is called____.
1. Intensity
2. attenuation
3. power
4. amplitude

Back 321

1. intensity

Front 322

As sound travels, the reduction in amplitude and intensity of the wave is called____.
1. reflection
2. scattering
3. attenuation
4. absorption

Back 322

3. attenuation

Front 323

The wavelength of 3 MHz ultrasound in soft tissue is _____ mm.
1. 5.1
2. .51
3. 510
4. 4.6

Back 323

2. .51

1.53mm/3 = .51mm

Front 324

What is the period of a 5.0 MHz in soft tissue.
1. 02 us
2. .2 us
3. 3.1 us
4. .2 sec

Back 324

2. .2 us

P= 1/f
1/5.0 = .2 us

Front 325

If you switch to a lower frequency for penetration, the wavelength of the transducer will ______?
1. remain unchanged
2. double
3. increase
4. decrease

Back 325

3. increase

Front 326

20 kHz is equal to _____ Hz.
1. 200,000
2. 2000
3. 20,000
4. 200

Back 326

3. 20,000

Front 327

What is the attenuation coefficient for a 5. MHz transducer in soft tissue.
1. .25 dB/cm
2. 10. dB/cm
3. .1 dB/cm
4. 2.5 dB/cm

Back 327

4. 2.5 dB/cm


1/2 frequency

Front 328

The attenuation of a 5.0MHz transducer at a depth of 4cm is _____ dB.
1. 20. dB
2. 16.0 dB
3. 1.6 dB
4. 10. dB

Back 328

4. 10.0 dB

1/2 frequency x imageing depth

Front 329

If the beam power increases, intensity will ____.
1. double
2. remain unchanged
3. decreased
4. increased

Back 329

4. increased.

Intensity = power/beam area

Front 330

Attenuation increased with increasing ____.
1. power
2. wavelenght
3. pressure
4. frequency

Back 330

4. frequency