Physics 2 Test chapters 12 &13 Flashcards by Cara Elmore

When the crystals are defective, the entire image is destroyed with this type of transducer

Single crystal transducer.
Mechanical transducer
Pg 167

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What’s the typical value for the electrical signal delay in a phased array transducer?

4-10 nanoseconds
notes and p. 172
??

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Which transducer creates a beam that is focused in all planes and at all depths?

annular phased array

quizlet???

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What is the advantage of using a 1 1/2 dimensional array transducer?

Addition of slice thickness/elevational resolution.

Pg188

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What type of resolutions are we considering with a 1 1/2 dimensional array transducer?

Slice thickness and
Elevational resolution
Pg 188

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What is the image shape of a vector array transducer?

Trapezoidal

Pg 187

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Which transducer has active elements arranged in a straight line?

Linear

Pg 168

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Which transducer has active elements arranged in circular rings?

Annular

Pg 168

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Which transducer has active elements arranged in an arched or bowed matter?

Convex

Pg168

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Phased array always means what?

Adjustable or multi-focused

Pg 170

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Linear switch transducer has what type of steering technique?

Also called linear sequential. Has electronic steering.

Pg 187

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What type of probe has dropout lines of image information from top to bottom?

Linear and convex

Pg187

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Horizontal or side to side dropout occurs in which transducer type when crystals are bad?

Annular phased array.

Pg187

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Which transducer is designed to be mechanically steered and fixed with single focus?

Mechanical

Pg187

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What is dynamic aperture?

“transmit hole” or “listening hole”
makes sound beam narrow over a greater range of depths
improves lateral resolution
Pg194

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What is the ultrasound machine that can display real time images and Doppler?

Duplex
pg 313
I just have a note I wrote in my book on pg 183 next to the bottom pic.

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The ability to accurately to locate moving structures at any time is what kind of resolution?

Temporal resolution

Pg 198

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What will decrease temporal resolution?

Deep imaging
Low frame rate
Pg 200

Real-time imaging could be referred to as…?

Ultrasound “movie”

Pg 197

What determines temporal resolution?

Frame rate

Pg198

What are the factors that limit frame rate?

speed of sound in the medium
Imaging depth
Pg 198

What will affect the pulses in a single image?

Number of focal points
Sector size
Line density
Pg 201

If we double imaging depth, what happens to frame rate?

Frame rate is halved

Pg 210

Imaging to greater depth of view requires what?

Long go-return time
Longer Tframe
Lower frame rate
Lower temporal resolution
Pg 200

What will degrade temporal resolution?

``` Deeper imaging Multiple focal points Wide sector High line density Pg 209 ```

What is the sector size that will use the fewest pulses?

The narrowest sector size | p. 204

The sonographer increases line density from 1 line to 3 lines, what will be the consequence of this action?

Temporal resolution decreases | p. 211

If the frame rate is 50 Hz, how long does it take to create a frame?

1/50 sec | p. 214 (#23 is an example of this)

Lateral resolution improves with what?

Multi-focus | p 209

Low line density creates what?

``` widely spaced lines fewer pulses per frame shorter T frame higher frame rate high temporal resolution poor spatial resolution p. 207 (yellow box) ```

What creates an image with poor movie quality but high image quality?

Poor temporal resolution Low frame rate Pg 208

Increasing the line density degrades _____ and improves _____.

Degrades temporal resolution and improves spatial resolution p. 207

A critical factor in determining frame rate, line density and imaging depth is?

Time | pg 213

If imaging depth is 15 cm and there’s 100 lines… | When frame is made quickly…how many Frames created per second?

100 frames per second p. 213 ???

Using a phased array ultrasound system, if you turn off the multi-focus feature what will most likely be a consequence of this action?

Temporal resolution increases | pg 211

Which of following is consistent with increased or improved spatial resolution?

High line density | p. 207

When a frame is made quickly, how many frames are created per second?

When you have 1 frame created in 1/100 second, what is the frame rate?

100 per second or 100 Hz | p. 213

What are the different shapes of images for all different probes?

``` Mechanical - sector Linear sequential - rectangle Phased array - sector Annular phased - sector Convex - blunted sector Vector - trapezoidal ```

Know about steering to the right and steering to the left

What is apodization?

Stronger electrical signals are used to excite inner crystals, and progressively weaker spikes excite the outer crystals then lobes are diminished p. 193

Focused and unfocused

What are side lobes and grating lobes?

Side lobes: sound beams created by single element transducers and are additional areas of sound energy extend outside of the main beam in the far zone Grating lobes: created by array transducers, the extra off-axis sound beams are undesirable because they degrade lateral resolution, reduce image quality, and create artifacts p. 192