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Sonography > Ch. 12 Physics: 2 dimensional Imaging > Flashcards

Ch. 12 Physics: 2 dimensional Imaging Flashcards

1
Q

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

A

Sound travels in a straight line.

Sound beams must be narrow to optimize lateral resolution.

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2
Q

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

A

Sending multiple pulses to create a 2D image

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3
Q

What does the initial pulse do?

A

Narrow pulses are sent into the body

Receives reflections

Processes and stores data

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4
Q

What does the second pulse do?

A

Sent in a slightly different direction than the first

Processes data

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5
Q

What does the third pulse do?

A

Sent again, slightly different direction

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6
Q

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

A

Mechanical transducer

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7
Q

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

A

fan or sector-shaped

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8
Q

How is fixed focus achieved?

A

Internal fixed focusing

External fixed focusing

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9
Q

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

A

Loss of the whole image

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10
Q

What are modern transducers called?

A

Arrays

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11
Q

Do arrays contain single or multiple active elements?

A

Multiple

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12
Q

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

A

Channel

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13
Q

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

A

True

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14
Q

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

A

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

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15
Q

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

A

Linear

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16
Q

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

A

Annular

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17
Q

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

A

Convex

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18
Q

How is a linear phased array steered focused?

A

Electronically

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19
Q

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?

A

90 degrees

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20
Q

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

A

Phased delay

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21
Q

What does sloped mean?

A

Steered

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22
Q

the electronics within the system that create these patterns.

A

Beam former

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23
Q

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

A

Beam former

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24
Q

What determines the direction of the sound beam?

A

The slope of the electrical spike

25
Q

the electrical signal creates a straight line

A

unfocused beam

26
Q

the electrical signals create curved lines

A

focused beam

27
Q

created by altering how curved the electricity signals are produced

A

Shallow vs deep focus

28
Q

What does it mean when the sound beam is curved?

A

It’s focused

29
Q

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

A

Multiple sound beams

30
Q

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

A

3

31
Q

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

A

True

32
Q

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

A

Shallow

33
Q

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

A

Deepest

34
Q

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

A

focused beams

35
Q

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

A

unfocused beams

36
Q

Which beam shape has no clinical significance or application?

focused

unfocused

A

unfocused

37
Q

What kind of focusing occurs during reception?

A

Dynamic Receive Focusing

38
Q

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

A

Dynamic receive focusing

39
Q

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

A

Reception

40
Q

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

A

optimal delays

41
Q

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

A

true

42
Q

Which phased array active elements appear disc-like?

A

Annular phased array

43
Q

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

A

true

44
Q

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

A

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

45
Q

a crystals diameter is _______ related to its focus depth.

A

directly

46
Q

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

A

shallowest

47
Q

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

A

deepen

48
Q

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

A

Only a portion of the image is lost

49
Q

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

A

rectangular images

50
Q

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

A

120- 250

51
Q

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

A

vertical

52
Q

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

A

True

53
Q

A rectangular grey
scale image is produced
with a ___________

A

linear sequential
array transducer.

54
Q

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

A

True

55
Q

In a convex array, the pulses travel ……

A

in different directions as they radiate out

56
Q

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

A

convex

57
Q

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

A

vertical

58
Q

Combines linear sequential and linear phased array technologies

A

Vector arrays

59
Q

Image shape is trapezoid for this transducer array.

A

Vector arrays

Sonography (39 decks)

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