Deck 3: Transducers

Question 1

In a single-element transducer,additional beams not included in the ultrasound beam are called _____________.

A) grating lobes
B) side lobes
C) slice thickness
D) scattering

Answer 1

B
In a single-element transducer,additional beams not included in the ultrasound beam are called side lobes.

Question 2

The useful frequency range for most diagnostic applications is ____________ MHz.

A) 1-15
B) 2-20
C) 2-15
D) 1-50

Answer 2

B
The useful frequency range for most diagnostic applications is 2-20 MHz.Frequencies up to 50 MHz are used in ophthalmologic,dermatologic,and intravascular imaging.

Question 3

The transducer element converts _________ to _______ and vice versa.

A) voltage; electricity
B) pulses; ultrasound
C) ultrasound; voltage
D) electricity; ultrasound

Answer 3

D
The transducer element refers to the piece of piezoelectric material that converts electricity to ultrasound and vice versa.

Question 4

Which of the following is attached to the rear face of the transducer element?

A) Damping.
B) Ceramics.
C) Matching layer.
D) Coupling media.

Question 5

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

Question 6

Which resolution relates more directly to transducers?

A) Temporal.
B) Contrast.
C) Vectoral.
D) Detail.

Question 7

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.

Question 8

The critical temperature an ultrasound transducer cannot exceed is called the ________.

A) Curie point
B) quality factor
C) critical point
D) piezoelectric point

Question 9

The transducer has an impedance ______ times that of tissue.

A) 4
B) 10
C) 20
D) 6

Question 10

Another name for the Fresnel zone is ________________.

A) near zone
B) far zone
C) field length
D) near path length

Question 11

The linear image consists of _______ scan lines.

A) vertical
B) oblique
C) horizontal
D) perpendicular

Question 12

Sequenced,phased,and vector are types of ________.

A) transducers
B) operations
C) focusing
D) construction

Question 13

Lateral resolution is equal to _____________.

A) wavelength/2
B) beam width
C) spatial pulse length/2
D) operating frequency/2

Question 14

Arrays are operated in two ways,called ___________ and ___________.

A) linear; convex
B) sequencing; phasing
C) pulse wave; continuous wave
D) spatial; angular

Question 15

If the propagation speed of the transducer element material is 6 mm/µs,the operating frequency for a thickness of 0.2 mm is ______ MHz.

A) 15
B) 30
C) 12
D) 7.5

Question 16

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

Question 17

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.

Question 18

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

Question 19

Coupling medium is applied to the transducer-tissue boundary to increase _________ of the sound wave.

A) reflection
B) scattering
C) refraction
D) transmission

Question 20

Electric _______ applied to a transducer are converted to ultrasound.

A) pulses
B) waves
C) echoes
D) voltages

Question 21

___________ array is the combination of linear and phased array operations.

A) Phased
B) Convex
C) Vector
D) Interventional

Question 22

Arrays have additional beams resulting from their multi-element structure called ________.

A) speckle
B) side lobes
C) refraction
D) grating lobes

Question 23

Partial-volume artifact is also called ____________.

A) section thickness artifact
B) side lobe artifact
C) refraction artifact
D) grating lobe artifact

Question 24

Invasive transducers ________.

A) decrease detail resolution
B) utilize smaller wavelengths
C) increase imaging depth
D) utilize lower frequencies

Question 25

The dimension perpendicular to the scan plane is called ________.

A) side lobes
B) section thickness
C) grating lobes
D) variable aperture

Question 26

Without 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%

Question 27

If the propagation speed of the transducer element is 4 mm/µs,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

Question 28

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.

Question 29

Increasing the transducer frequency decreases the ________.

A) frame rate
B) detail resolution
C) propagation speed
D) maximum imaging depth

Question 30

The purpose of the coupling medium is ________.

A) to provide patient comfort
B) to produce an air pocket
C) to reduce the number of cycles in a pulse
D) to facilitate passage of ultrasound into human tissue

Question 31

Ultrasound transducers operate according to _____________.

A) Snell's law
B) Huygen's principle
C) the piezoelectric principle
D) the piezoenergy principle

Question 32

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

Question 33

Electronic scanning is performed by ________ transducers.

A) linear
B) array
C) sector
D) mechanical

Question 34

In a curved array,the pulses travel ________.

A) out in different directions
B) in straight lines
C) faster in the center of the beam
D) from an apex

Question 35

Which image format is similar to that for convex array except that the footprint is smaller?

A) Sector.
B) Vector.
C) Curvilinear.
D) Interventional.

Question 36

Phasing can ________.

A) focus the beam
B) improve the image quality
C) steer the beam
D) All of the above.

Question 37

The three aspects to imaging resolution are contrast,temporal,and ________ resolution.

A) depth
B) angular
C) detail
D) spatial

Question 38

Shortening the pulses in diagnostic ultrasound broadens the ______________.

A) bandwidth
B) duty factor
C) pulse duration
D) lateral resolution

Question 39

Which of the following describes the far zone?

A) It lies within one near zone length.
B) It is called the Fresnel zone.
C) Its beam width (diameter) increases with increasing depth.
D) The length of the far zone increases with increases in frequency.

Question 40

Linear and convex are types of ________ arrays.

A) focusing
B) operation
C) assembly
D) scanning

Question 41

Axial resolution is determined by the width of the ultrasound beam.

Question 42

The focal length is the distance between equal beam widths that are some multiple of the minimum value at the focus.

Question 43

Utilization of multiple focal points is likely to achieve a ________.

A) short focus
B) narrow focus
C) long focus
D) wide focus

Question 44

As sound travels,the width of the beam remains unchanged.

Question 45

The matching layer increases reflection of the transducer element.

Question 46

Which of the following is achieved 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.

Question 47

With phasing,the reception beam is ________ and dynamically ________.

A) focused; steered
B) steered; focused
C) variable; focused
D) generated; received

Question 48

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.

Question 49

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

Question 50

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

Question 51

Continuous-wave (CW) transducers have higher efficiencies because energy is not lost to damping material.

Question 52

Axial resolution is the ________.

A) minimum separation necessary to resolve reflectors along the scan line
B) ability to differentiate similar and dissimilar tissue
C) minimum separation necessary to resolve reflectors perpendicular to the beam direction
D) ability to differentiate a moment in time

Question 53

If the aperture increases,the near-zone length ________.

A) doubles
B) increases
C) decreases
D) remains unchanged

Question 54

The operating frequency depends on the element propagation speed and thickness

Question 55

Many frequencies are present in short pulses.

Question 56

Utilizing multiple focal zones simultaneously increases image detail resolution and degrades ________.

A) contrast resolution
B) temporal resolution
C) sectional thickness
D) harmonic frequencies

Question 57

Damping material in pulsed transducers increases the spatial pulse length.

Question 58

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

Question 59

The near-zone length decreases with an increase in frequency.

Question 60

Lateral resolution remains consistent at any depth.

Question 61

Wide bandwidth allows harmonic imaging.

Question 62

The three aspects of imaging resolution include axial,contrast,and temporal resolution.

Question 63

Multi-Hertz transducers are driven at only one selectable frequency.

Question 64

The frequency of a transducer is determined by the diameter and the propagation speed of the element.

Question 65

Even unfocused transducers have a natural focus.

Question 66

Elevational resolution can be considered a third aspect of detail resolution.

Question 67

Various formulations of lead zirconate titanate are commonly used in modern day transducers.

Question 68

Focusing in the section-thickness plane reduces section thickness artifact.

Question 69

Intensity is uniform throughout the beam.

Question 70

Axial resolution is often normally better than lateral resolution.

Question 71

Minimum reflector separation in the direction perpendicular to the beam direction describes axial resolution.

Question 72

Ceramics used as materials in the production of modern ultrasound transducer elements are naturally piezoelectric.

Question 73

Beam width can be reduced by focusing to improve lateral resolution.

Question 74

Contrast and temporal resolution relate more directly to the transducer.

Question 75

The thicker the section thickness,the less its negative impact on sonographic images.