Ch. 3 Flashcards Preview

Physics Final > Ch. 3 > Flashcards

Flashcards in Ch. 3 Deck (50):
1

Coupling medium is applied to the transducer-tissue boundary to increase _______ of the sound wave.
a. reflection
b. scattering
c. refraction
d. transmission

d. transmission

2

Arrays are operated in two ways, called _____ and _____.
a. linear; convex
b. sequencing; phasing
c. pulse wave; continuous wave
d. spatial; angular

b. sequencing; phasing

3

The transducer element converts _____ to ______ and vice versa.
a. voltage; electricity
b. pulses; ultrasound
c. ultrasound; voltage
d. electricity; ultrasound

d. electricity; ultrasound

4

Which of the following frequencies is operated by the thinnest element?
a. 2.5 MHz
b. 3.5 MHz
c. 7.5 MHz
d. 10.0 MHz

d. 10.0 MHz

5

At a distance of two near-zone lengths, the beam diameter is _____ the diameter of the transducer element.
a. one half of
b. double
c. equal to
d. triple

c. equal to

6

The transducer has an impedance ______ times that of the tissue
a. 4
b. 10
c. 20
d. 6

c. 20

7

The linear image consists of ____ scan lines.
a. vertical
b. oblique
c. horizontal
d. perpindicular

a. vertical

8

Another name for the Fresnel zone is _________.
a. near zone
b. far zone
c. field length
d. near path length

a. near zone

9

In a single-element transducer, additonal beams are not included in the ultrasound beam are called _______.
a. grating lobes
b. side lobes
c. slice thickness
d. scattering

b. side lobes

10

Lateral resolution is equal to _____.
a. wavelength/2
b. beam width
c. spatial pulse length/2
d. operating frequency/2

b. beam width

11

The useful frequency range for most diagnostic applications is _____ MHz.
a. 1 - 15 MHz
b. 2 - 20 MHz
c. 2 - 15 MHz
d. 1 - 50 MHz

b. 2 - 20 MHz

12

Factors determining axial resolution are the ______.
a. frequency and wavelength
b. beam diameter and element thickness
c. number of cycles in the pulse and wavelength
d. propagation speed and number of cycles in a pulse

c. number of cycles in the pulse and wavelength

13

The matching layer _________.
a. reduces reflection of ultrasound at element
b. reduces transmission of ultrasound at element
c. increases reflection of the ultrasound element
d. increases the spatial pulse length

a. reduces reflection of ultrasound at element

14

What principle states that some materials produce a voltage when deformed by an applied pressure?
a. ALARA (as low as reasonably achievable) principle
b. Piezoelectric principle
c. Snell's principle
d. Huygens' principle

b. Piezoelectric principle

15

Electric _____ applied to a transducer are converted to ultrasound.
a. pulses
b. waves
c. echoes
d. voltages

d. voltages

16

Sequenced, phased, and vector are types of ______.
a. transducer
b. operations
c. focusing
d. construction

b. operations

17

Which resolution relates more directly to the transducers?
a. Temporal
b. Contrast
c. Vectoral
d. Detail

d. Detail

18

If the propagation speed of the transducer element material is 6 mm/us, the operating frequency for a thickness of .2 mm is ____ MHz.
a. 15
b. 30
c. 12
d. 7.5

a. 15

19

The critical temperature an ultrasound transducer cannot exceed is called the _____.
a. Curie point
b. quality factor
c. critical point
d. piezoelectric point

a. Curie point

20

Which of the following is attached to the rear face of the transducer element?
a. Damping
b. Ceramics
c. mathcing layer
d. puling media

a. damping

21

Ultrasound transducers operate according to ______.
a. Snell's law
b. Huygens prinicple
c. the piezoelectric principle
d. the piezoenergy principle

c. the piezoelectric principle

22

Shortening the pulses in diagnostic ultrasound broadens the _______.
a. bandwidth
b. duty factor
c. pulsed duration
d. lateral resolution

a. bandwidth

23

Which image format is similar to that for convex array except that the footprint is smaller?
a. Sector
b. Vector
c. Curvilinear
d. Interventional

b. Vector

24

Partial-volume artifact is also called ____.
a. section-thickness artifact
b. side lobe artifact
c. refraction artifact
d. grating lobe artifact

a. section thickness artifact

25

The near-zone length is determined by the size and the _____ of the element.
a. thickness
b. propagation speed
c. operating frequency
d. all of the above

c. operating frequency

26

Intravascular imaging generally utilizes a frequency range _____.
a. between 2.5 and 5.0 MHz
b. between 5.0 and 7.5 MHz
c. between 10.0 and 15 MHz
d. up to 50 MHz

d. up to 50 MHz

27

Linear and convex are types of ______ arrays.
a. focusing
b. operation
c. assembly
d. scanning

c. assembly

28

The three aspects to imaging resolution are contrast, temporal, and ______ resolution.
a. depth
b. angular
c. detail
d. spatial

c. detail

29

If the propagation speed of the transducer element is 4 mm/us, the thickness required for an operating frequency of 10 MHz is _____.
a. 0.4 mm
b. 0.8 mm
c. 0.2 mm
d. 0.1 mm

c. 0.2 mm

30

Increasing the transducer frequency decreases the ____.
a. frame rate
b. detail resolution
c. propagation speed
d. maximum imaging depth

d. maximum imaging depth

31

The purpose of the coupling medium is _____.
a. to provide the patient comfort
b. to produce an air pocket
c. to reduce the number of cycle in a pulse
d. to facilitate passage of ultrasound into human tissue

d. to facilitate passage of ultrasound into human tissue

32

Invasive transducers ____.
a. decrease detail resolution
b. utilize smaller wavelengths
c. increase the imaging depth
d. utilize lower frequencies

b. utilize smaller wavelengths

33

W/o compensation, the ultrasound transducer would cause about ____ of the emitted intensity to be reflected at the skin boundary.
a. 25%
b. 80%
c. 10%
d. 50%

b. 80%

34

Which of the following describes the far zone?
a. it lies within onear near zone length
b. it is called the Freznel zone
c. its beam width (diameter) increases with increasing depth
d. the length of the far zone increases with increases in frequency

c. its beam width (diameter) increases with increasing depth

35

In a curved array, the pulses travel _____.
a. out in different directions
b. in straight lines
c. faster in teh center of the beam
d. from an apex

a. out in different directions

36

Electronic scanning is performed by ____ transducers.
a. linear
b. array
c. sector
d. mechanical

b. array

37

Phasing can ____.
a. focus the beam
b. improve the image quality
c. steer the beam
d. all of the above

d. all of teh above

38

The dimension perpendicular to the scan plane is called ______.
a. side lobes
b. section thickness
c. grating lobes
d. variable aperture

b. section thickness

39

Arrays have additonal beams resulting from their multi-element structure called _____.
a. speckle
b. side lobes
c. refraction
d. grating lobes

d. grating lobes

40

______ array is the combination of linear and phased array operations.
a. Phased
b. Convex
c. Vector
d. Interventional

c. Vector

41

With phasing, the reception beam is ______ and dynamically ______.
a. focused; steered
b. steered; focused
c. variable; focused
d. generated; received

b. steered; focused

42

If the aperture increases, the near-zone length ______.
a. doubles
b. increases
c. decreases
d. remains unchanged

b. increases

43

The impedance of the matching layer is ______.
a. an intermediate value between the transducer element and tissue
b. greater than the value between the transducer element and tissue
c. less than the value between the transducer element and tissue
d. equal to the impedance of tissue

a. an intermediate value between the transducer element and tissue

44

Axial resolution is the ______.
a. minimum seperation necessary to resolve reflectors along the scan line
b. ability to differentiate similar and dissimilar tissue
c. minimum seperation necessary to resolve reflectors perpendicular to the beam direction
d. ability to differentiate a moment in time

a. minimum separation necessary to resolve reflectors along the scan line

45

The distance from the transducer to the center of the focal region is called the _____.
a. focus
b. path length
c. focal length
d. focal zone length

c. focal length

46

Which of the following determines the beam width at the focus?
a. focal length and frequency
b. aperture, focal length, and wavelength
c. aperture, propagation speed, and thickness
d. spatial pulse length and propagation speed of the element

b. aperture, focal length, and wavelength

47

Utilization of multiple focal points is likely to achieve a ______.
a. short focus
b. narrow focus
c. long focus
d. wide focus

c. long focus

48

Utilizing multiple focal zones simultaneously increases image detail resolution and degrades _____.
a. contrast resolution
b. temporal resolution
c. sectional thickness
d. harmonic frequencies

b. temporal resolution

49

Which of the following is achoeved within the Fresnel zone?
a. focusing of the sound beam
b. divergence of the sound beam
c. increasing of the beam width
d. uniform intensity of the sound beam

a. focusing of the sound beam

50

With a linear phased array transducer, the elements measure the width of about _____.
a. one wavelength
b. two wavelengths
c. one half of a wavelength
d. one quarter of a wavelength

d. one quarter of a wavelength