Physics Ch 10, 11, 24 Flashcards Preview

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Flashcards in Physics Ch 10, 11, 24 Deck (25)
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1

The ability to accurately distinguish two structures lying close together is called?

Resolution

2

T/F Axial and lateral resolution are both measured in units of time

False- Measured in distance

3

T/F Continuous wave frequency is determined by the beam width

False- Determined by frequency of electrical signal from ultrasound system

4

T/F The thickness of the ceramic and the speed of sound in the ceramic are determining factors for pulsed wave frequency

True

5

T/F Lateral resolution is equal to beam width

True

6

T/F Phased array transducers have the electronic focusing

True

7

T/F Phased array electronic focusing technique can always be used in single element transducers

False-used only on multi-element transducers, never on single crystal transducers

8

With which of the following operations can lateral resolution of a given depth be estimated

,

9

LATA

Lateral Angular Transverse Azimuthal

10

LARRD

Longitudinal Axial Range Radial Depth

11

The length of a pulse is 10 mm. What is the minimum distance between two reflectors, positioned one in front of the other, that still produces two echoes on our image?

5 mm

*Value is one-half the pulse length

12

Fixed focus transducers have what type of lateral resolution

poor lateral resolution

13

Lateral resolution

The ability to distinctly identify two structures that are very close together when they are side by side, or perpendicular, to the sound beam's main axis

14

Lateral resolution is best at the focus where the beam is..

narrowest

15

The effects of focusing

-Beam diameter in near field and focal zone is reduced
-Focal depth is shallower
-Beam diameter in the far zone increases
-Focal zone is smaller

16

Three methods of focusing

-External focusing
-Internal focusing
-Phased array focusing

17

Better axial resolution is associated with ___ cycles per pulse and ___ numerical values

Fewer, Lower

18

What type of transducers have the poorest axial resolution?

Longest pulse, lowest frequency, and the most ringing (more cycles/pulse)

19

In soft tissue, a 3 cycle, 1 MHz pulse has a pulse length equal to 4.5 mm. What is the axial resolution?

2.25 mm

* 4.5 mm/2 = 2.25 mm

20

What happens to the numerical value of range resolution when the number of cycles changes but the frequency stays the same

,

21

What display mood provides information regarding reflector motion?

M-mode

22

X-axis, Y-axis, Z-axis

,

23

A-mode

,

24

B-mode

,

25

M-mode

,