Cpt 10 Notes

Question 1

Describes the detail that is displayed an determines the image accuracy

Answer 1

Resolution

Question 2

More/better/higher resolution means a _________ picture.

Answer 2

More accurate

Question 3

Types of resolution:

Answer 3

Axial
Lateral
Temporal
Elevational

Question 4

The ability of the system to display 2 structures parallel to the sound beam’s axis is ______

Answer 4

Axial resolution

Question 5

Shorter pulses= _______ image quality

Answer 5

better

Question 6

Axial resolution units:

Answer 6

mm (any distance)

Question 7

Axial resolution is determined by:

Answer 7

SPL (medium and source) & PD

Question 8

Axial resolution synonyms:

LARRD

Answer 8

Longitudinal
Axial
Range
Radical
Depth resolution

Question 9

Is axial resolution adjustable?

Answer 9

No. SPL is fixed, therefor axial resolution is fixed.

Question 10

Axial resolution typical values:

Answer 10

10 to 1.0 mm (Less is better)

Question 11

Long SPL= _______ axial resolution

Answer 11

Bad

Question 12

Short SPL= _______ axial resolution.

Answer 12

Good

Question 13

Axial Resolution formula:

Answer 13

AR=SPL (mm)/2

Question 14

Spatial pulse length formula:

Answer 14

Wavelength (mm) x # of cycles in pulse

Question 15

Axial resolution in soft tissue formula:

Answer 15

AR (mm)=0.77 x # of cycles in pulse/Frequency (MHz)

Question 16

What is determines by the pulse length?

Answer 16

Axial resolution

Question 17

Two factors that help create short pulses:

Answer 17

Less ringing

Higher Frequency

Question 18

What causes shorter pulses in a transducer because of less ringing?

Answer 18

Backing material

Question 19

What creates short pulses because the wavelength is shorter?

Answer 19

Higher frequencies

Question 20

When a pulse has fewer cycles in it, it is short and this is known as _________.

Answer 20

Less ringing

Question 21

(AR)

Long pulse= _________=__________

Answer 21

More ringing

Poor axial resolution

Question 22

(AR)

Short pulse= _________=___________

Answer 22

More ringing

Poor axial resolution

Question 23

(AR)

Low frequency=____________=___________=__________

Answer 23

Long wavelength
Long pulse
Poor axial resolution

Question 24

(AR)

High frequency= _________=__________=___________

Answer 24

Short wavelength
short pulse
Improved axial resolution

Question 25

Better axial resolution is seen with:

Answer 25

``` Shorter SPL Shorter PD Higher frequencies (shorter wavelengths) Fewer cycles per pulse (less ringing) Lower numerical values ```

Question 26

The amount of detail or accuracy when reflectors are perpendicular to the sound beam is _______

Answer 26

Lateral resolution

Question 27

Lateral resolution units is ___

Answer 27

mm (any distance)

Question 28

Lateral resolution is determined by:

Answer 28

Width of beam

Question 29

Lateral resolution synonyms: | LATA

Answer 29

Lateral Angular Transverse Azimuthal

Question 30

Lateral resolution formula:

Answer 30

Lateral resolution (mm)=beam diameter (mm)

Question 31

Higher frequencies will improve both ________ and ________ resolution

Answer 31

Axial | Lateral

Question 32

(LR) | Higher frequency=______ pulse length =_________ axial resolution

Answer 32

Short | Better

Question 33

(LR) | High frequency=_______ beam divergence=______ lateral resolution (in the far field)

Answer 33

Less | Better

Question 34

Lateral resolution is best with _____

Answer 34

narrowest beam

Question 35

Lateral resolution changes with ______, best at ______.

Answer 35

Depth | focus

Question 36

Axial resolution is beast in the near field with __________ and best in the far field with _________

Answer 36

Shortest pulse | Shortest pulse

Question 37

Lateral resolution is best in the near field with _________ and best in the far field with _______

Answer 37

Smallest diameter crystal | Largest diameter crystal

Question 38

Three methods for focusing:

Answer 38

External Internal Phased array focusing

Question 39

External focus is fixes which means ________.

Answer 39

It cannot be changed

Question 40

External focusing is achieved by placing a ______ in front of the PZT crystal.

Answer 40

Curved lens

Question 41

Internal focusing is fixed meaning that ______.

Answer 41

It cannot be changed

Question 42

Internal focusing is achieved by creating a PZT crystal with a _______.

Answer 42

Curve

Question 43

Electronic focus is ________, meaning that it can be changed.

Answer 43

Dynamic

Question 44

Electronic focusing is only seen in transducers that have _______.

Answer 44

Multiple elements

Question 45

Electronic focusing is achieved by __________.

Answer 45

Creating a delay in the excitation of each element.

Question 46

What happens when a sound beam undergoes focusing?

Answer 46

Near zone diameter is less The focus is closer to the transducer More widening in the far field The focal zone size is reduced