Ch. 12 Physics: 2 dimensional Imaging

Question 1

what are the two characteristics of sound that make 2D imaging challenging?

Answer 1

Sound travels in a straight line.

Sound beams must be narrow to optimize lateral resolution.

Question 2

How do you overcome both of the difficulties in 2D imaging?

Answer 2

Sending multiple pulses to create a 2D image

Question 3

What does the initial pulse do?

Answer 3

Narrow pulses are sent into the body

Receives reflections

Processes and stores data

Question 4

What does the second pulse do?

Answer 4

Sent in a slightly different direction than the first

Processes data

Question 5

What does the third pulse do?

Answer 5

Sent again, slightly different direction

Question 6

What kind of transducer contains a single, circular, disc-shaped active element that is physically moved.

Answer 6

Mechanical transducer

Question 7

What kind of image shape is created with a mechanical transducer?

Answer 7

fan or sector-shaped

Question 8

How is fixed focus achieved?

Answer 8

Internal fixed focusing

External fixed focusing

Question 9

In a mechanical transducer, what happens to when the active element is damaged?

Answer 9

Loss of the whole image

Question 10

What are modern transducers called?

Answer 10

Arrays

Question 11

Do arrays contain single or multiple active elements?

Answer 11

Multiple

Question 12

the combination of the active element, wire, and system electronics

Answer 12

Channel

Question 13

True or false:
Each single crystal or groups of crystals can be excited separately during transmission.

Answer 13

True

Question 14

True or false:
Each element is connected by a wire to a group of electronic circuitry.

Answer 14

False
Each element is connected by a wire to its own electronic circuitry

Question 15

What type of transducer arrays have the active elements arranged in a straight line?

Answer 15

Linear

Question 16

What type of transducer arrays have the elements arranged as circular rings with a common center?

Answer 16

Annular

Question 17

What type of transducer arrays have the elements arranged in a bowed or arched line? Also called a curved, or a curvilinear array.

Answer 17

Convex

Question 18

How is a linear phased array steered focused?

Answer 18

Electronically

Question 19

In a linear phased array, all elements are fired to create each sound pulse. Since all are fired at once, what is the degree angle?

Answer 19

90 degrees

Question 20

10-nanosecond time differences between many wavelets to create a single unified sound beam that is directed to the side.

Answer 20

Phased delay

Question 21

What does sloped mean?

Answer 21

Steered

Question 22

the electronics within the system that create these patterns.

Answer 22

Beam former

Question 23

the internal component within the system that determines the firing delay patterns for phased array systems.

Answer 23

Beam former

Question 24

What determines the direction of the sound beam?

Answer 24

The slope of the electrical spike

Question 25

the electrical signal creates a straight line

Answer 25

unfocused beam

Question 26

the electrical signals create curved lines

Answer 26

focused beam

Question 27

created by altering how curved the electricity signals are produced

Answer 27

Shallow vs deep focus

Question 28

What does it mean when the sound beam is curved?

Answer 28

It's focused

Question 29

To create an image with multiple foci at different depths, the system must send _________ _________ _________down each scan line

Answer 29

Multiple sound beams

Question 30

For 3 focal points, each scan line must have ___ separate pulses, one for each focal zone.

Answer 30

3

Question 31

True or false: All pulses will have different curvatures to their path.

Answer 31

True

Question 32

The greatest curvature creates the beam with the most ________ focus.

Answer 32

Shallow

Question 33

The beam with the least curved pattern, will create the _______ focus.

Answer 33

Deepest

Question 34

What kind of beams outer spikes are fired first, creating the concave curved appearance?

Answer 34

focused beams

Question 35

What kind of beam center spike is fired first, creating a D-shaped, convex appearance?

Answer 35

unfocused beams

Question 36

Which beam shape has no clinical significance or application? focused unfocused

Answer 36

unfocused

Question 37

What kind of focusing occurs during reception?

Answer 37

Dynamic Receive Focusing

Question 38

This automatic focusing is performed by the system and cannot be adjusted by the sonographer.

Answer 38

Dynamic receive focusing

Question 39

During __________, when reflected sound arrives at the transducer, multiple neighboring elements in the probe are excited.

Answer 39

Reception

Question 40

The ________ ________ used during receive focusing depend on the depth at which the reflection was created.

Answer 40

optimal delays

Question 41

True or false: Dynamic receive focusing is applied to all depths along the scan line

Answer 41

true

Question 42

Which phased array active elements appear disc-like?

Answer 42

Annular phased array

Question 43

True or false: in annular phased array transducers, the disc has multiple ring-shaped elements with a common center.

Answer 43

true

Question 44

True or false: in annular phased array, beam steering is available.

Answer 44

False Mechanical steering creates the two-dimensional image as sound beams are transmitted in different directions by a motor that physically moves the ringed-element

Question 45

a crystals diameter is _______ related to its focus depth.

Answer 45

directly

Question 46

in annular phased array, The inner crystal (the smallest) will create the _________ focus.

Answer 46

shallowest

Question 47

in annular phased array, The focus depths will continue to _________ as the crystal’s diameter increases from the center.

Answer 47

deepen

Question 48

When one ring of an annular array transducer malfunctions, what happens to the image?

Answer 48

Only a portion of the image is lost

Question 49

Linear Sequential arrays have a much larger footprint and create _______ images.

Answer 49

rectangular images

Question 50

How many rectangular-shaped strips of PZT material arranged side by side in linear sequential arrays?

Answer 50

120- 250

Question 51

In linear sequential array, damaged crystals create a loss of image in a _______ line.

Answer 51

vertical

Question 52

True or false: The rectangular shaped image is never wider than the footprint of the transducer

Answer 52

True

Question 53

A rectangular grey scale image is produced with a ___________

Answer 53

linear sequential array transducer.

Question 54

True or false: curved transducers are very similar to linear array transducers.

Answer 54

True

Question 55

In a convex array, the pulses travel ......

Answer 55

in different directions as they radiate out

Question 56

for this transducer the image is described as a blunted sector-shaped.

Answer 56

convex

Question 57

In a convex transducer, damaged crystals create a __________ loss of image in the line where the damaged crystal is defective.

Answer 57

vertical

Question 58

Combines linear sequential and linear phased array technologies

Answer 58

Vector arrays

Question 59

Image shape is trapezoid for this transducer array.

Answer 59

Vector arrays