practice exam Flashcards

1
Q

Which transducers fires the elements in groups?

A

linear sequenced array

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2
Q

What is the highest attenuator in U/S?

A

air

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3
Q

What has the highest prop velocity?

A

bone

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4
Q

What is the intensity equation?

A

Power/area

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5
Q

Which of the following has the lowest intensity?

a. SPTP
b. SATP
c. SPTA
d. SATA

A

SATA

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6
Q

What is the definition of the beam uniformity ratio?

A

SP/SA

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7
Q

Ultrasound attenuates an average of ___________________dB/cm of
travel for each megahertz of frequency.

A

0.7

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8
Q

If medium 2 impedance is equal to medium 1 impedance:

A

100% transmission

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9
Q

What is the measurement for impedance?

A

Raylz

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10
Q
  1. A decibel (dB) describes the:
    a. Ratio of two sound intensities
    b. Sum of two sound intensities
    c. Amount of scattering
    d. Velocity of the sound wave
A

Ratio of 2 sound intensities

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11
Q

The attenuation coefficient of sound in soft tissue can be defined by what equation?

A

freq/2

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12
Q

Diffraction refers to

A

spreading out of the beam

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13
Q

The echoes are stored before final display by the:

A

Scan converter

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14
Q

What component of the ultrasound system contains the digital-to analog converter?

A

Scan converter

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15
Q

How many different shades of gray can the human eye discern at one
time?

A

about 100

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16
Q

The spatial resolution capabilities of the system are mainly functions of the:

17
Q

What is infrasound?

A

sound with a frequency less than 20 Hz

18
Q

What is audible sound?

A

s in the frequency range of 20 to 20,000 Hz

19
Q

How dp you adjust the PRF?

A

by adjusting the depth

20
Q

When is angle 2 less than angle 1

A

if speed of medium 2 is less than the speed of angle 1

21
Q

What is propogation speed determined by?

A

Propagation speed is only determined by the medium (specifically stiffness and density

22
Q

Unit for intensity

23
Q

What testing device is used to measure acoustic output (intensity)
level?

A

hydrophone

24
Q

radial resolution is another name for?

A

axial resolution

25
Axial resolution formula
1/2 SPL
26
In the most common type of transducers, the slice-thickness plane is focused by using?
a lens
27
What is the relationship of propogation speed and frequency?
unrelated, dont alter eachother
28
Which law describes the relationship between flow and the pressure differential, viscosity, and length?
Poisuelles
29
M/C flow in the body
Laminar