Physics Test Ch. 14 and 15

Question 1

Which component of an Ultrasound system is responsible for organization and time?

Answer 1

Master synchronizer Pg 216

Question 2

Which component of an Ultrasound system creates an electrical signal that excites the PZT?

Answer 2

Pulser Pg 217

Question 3

The anatomy area of the TGC curve where attenuation occurs

Answer 3

Slope

Question 4

What part creates the firing pattern for a phased array system?

Answer 4

Beam Former Pg 221

Question 5

What are all of the receiver functions?

Answer 5

1. Amplification
2. Compensation
3. Compression
4. Demodulation
5. Reject Pg 223

Question 6

Acoustic power of a sound beam is determined by what part of a pulser?

Answer 6

Voltage Pg 237

Question 7

What type of pulser generates constant electrical signal in the form of a sine wave?

Answer 7

Continuous wave Pg 236

Question 8

What is the function that will improve signal to noise?

Answer 8

increasing output power is the most common way to improve signal to noise pg 219

Question 9

What is the receiver function that has to do with demodulization?

Answer 9

Rectification Or Smoothing Pg 232

Question 10

What is the receiver function that keeps ______ within range of the human eye?

Answer 10

Compression Gray scale Pg 230

Question 11

What is the receiver function that is not adjustable by the sonographer?

Answer 11

Demodulation Pg 232

Question 12

When an image is too dark or too bright, what are your two options to adjust the image?

Answer 12

output power (if image is too bright) and receiver gain (if image is too dark)

Question 13

Which receiver function treats signals differently depending on depth?

Answer 13

Compensation Pg 226

Question 14

What is the receiver function that affects the weak signals, leaving the strong signals unchanged?

Answer 14

Reject Pg 233

Also known as suppression and threshold

Question 15

When PRP is long, PRF will be? And how does this affect listening?

Answer 15

-Lower
-Longer listening time
Pg 220 (deep imaging)

Question 16

Know all six components of an ultrasound system

Answer 16

• Transducer
• Pulser and beam former
• Receiver
• Display
• Storage
• Master synchronizer Pg 216

Question 17

What should you do if an ultrasound system displays reflectors only in the far region?

Answer 17

Adjust the systems compensation pg 238

Question 18

What is the best choice if the entire image is too bright?

Answer 18

Decrease the output power pg 238

Question 19

Which component will affect strength of every pulse transmitted into the body?

Answer 19

Amplification Pg 224

Question 20

What are some disadvantages of analog scan converters?

Answer 20

• image fade
• image flicker
• instability
• deterioration pg 243

Question 21

Which electronic component is required for gray scale imaging?

Answer 21

Scan converter

Question 22

Read magnification

Answer 22

Occurs after the image data is stored in the scan converter; displaying original data.
Number of pixels in the image stay the same which makes the pixels larger when zoomed in p250

Question 23

Temporal resolution may be improved if the region of interest is _____ in comparison to the original?

Answer 23

If the bottom of the region of interest is shallower that the original image’s depth of view pg. 252

Question 24

Advantages of an analog scan converter

Answer 24

Unlimited and continuous range of values
Real world-numbers that are found in our everyday lives
Spatial resolution is improved because of the large number of storage elements

Question 25

How many shades of gray are represented by 5 bits

Answer 25

32 | 2*2*2*2*2=32

Question 26

How many bits are needed to store certain amount of shades of gray. Example: 10 shades of gray? 11 shades of gray? 15 shades of gray?

Answer 26

Four bits are required to store from 9 to 16 shades of gray

Question 27

What are the preprocessing functions?

Answer 27

All the changes made to an image before storage. - time gain compensation - log compression - write magnification - persistence - spatial compounding - edge enhancement - fill in interpolation pg 249

Question 28

Know about pixels

Answer 28

``` Smallest building block of a digital picture; number of picture elements per inch -Low pixel density: few pixels/inch larger pixels less detailed image lower spatial resolution -High pixel density: many pixels/inch smaller pixels more detailed image higher spatial resolution pg. 244 ```

Question 29

Know the diagram on pg. 247 about digital and analog

Answer 29

analog------->analog-to-digital converter -------> digital memory (zeros and ones) -------> digital-to-analog converter --------> analog pg. 247

Question 30

Bistable imaging

Answer 30

Images are composed of black and white shades only. pg 239

Question 31

Spatial resolution of the CRT is determined by what? (Beth said "CRT" means "screen/monitor")

Answer 31

Pixel density Pg. 377

Question 32

What function is related to the ability for us to see shades of gray?

Answer 32

Compression pg 230

Question 33

Real world vs. computer world

Answer 33

real world is analog and computer world is digital 242

Question 34

While scanning, you increase your overall gain. Is this preprocessing or postprocessing?

Answer 34

Preprocessing pg. 249

Question 35

Preprocessing

Answer 35

The manipulation of image data before storage in the scan converter; sonographer controls this; alters image data forever and cannot be reversed/undone pg. 249

Question 36

Postprocessing

Answer 36

The manipulation of image data after storage in the scan converter; sonographer controls this; since this occurs after A-to-D conversion and storage, all changes can be reversed; any alterations to a frozen image must be postprocessing - Any change after freeze frame - Black/white inversion - Read magnification - Contrast variation - 3-D rendering pg. 249

Question 37

What portion converts data into numbers?

Answer 37

Digital scan converter Pg. 243

Question 38

What are the advantages of coded excitation?

Answer 38

- Higher signal-to-noise ratio - Improved axial resolution - Improved spatial resolution - Improved contrast resolution - Deeper penetration pg. 253

Question 39

What is fill-in interpolation?

Answer 39

Fill in the gaps of missing data in a way that cannot be detected by the observer; form of preprocessing pg. 257

Question 40

What is coded excitation? (where does it occur)

Answer 40

Creates very long sound pulses containing a wide range of frquencies. Occurs in the pulser. pg. 253

Question 41

What is spatial compounding?

Answer 41

Spatial compounding averages multiple frames obtained by steering the sound beam in different directions

Question 42

What is elastography?

Answer 42

Produces images from sound reflection. Images are relayed to mechanical properties of tissue. Theory of elastography is that tissue will deform differently following the application of a force. Estimates tissue stiffness. pg 258

Question 43

Which technology reduces speckle and improves spatial resolution?

Answer 43

Spatial compounding pg. 254

Question 44

What is speckle?

Answer 44

is noise resulting from constructive and destructive interference of small sound wavelets. pg 374

Question 45

Which technology provides a history of past frames that overlay on the present frames?

Answer 45

temporal compounding, persistence, or temporal averaging pg 256

Question 46

This type of pulser generates numerous electrical spikes, which ultimately create a single sound pulse

Answer 46

Pulsed wave, phased array p 237

Question 47

Demodulation

Answer 47

- fourth function of the receiver - is a two-part process that changes the electrical signals within the receiver into a form more suitable for display on a monitor

Question 48

when determining receiver gain or output power which should be in the main concern

Answer 48

ALARA/bioeffects

Question 49

The signal from the transducer to the receiver is what?

Answer 49

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