Ultrasound Transducers

Question 1

The widening of the sound beam in the far field

Answer 1

angle of divergence

Question 2

size of the transducer elements

Answer 2

aperture

Question 3

nonuniform driving (excitation) of the elements in an array to reduce grating lobes

Answer 3

apodization

Question 4

collection of active elements connected to individual electronic currents in one transducer assembly

Answer 4

array

Question 5

ability to distinguish two structures along a path parallel to the sound beam

Answer 5

axial resolution

Question 6

multiple transducer elements with individual wiring and system electronics

Answer 6

channels

Question 7

occurs when two waves in phase with each other create a new wave with amplitude greater than the original two waves: in phase

Answer 7

constructive interference

Question 8

curved linear transducer containing multiple pizoelectric elements

Answer 8

convex array

Question 9

pizoelectric element

Answer 9

crystal

Question 10

temp to which a material is raised, while in the presence of a strong electrical field, to yield piezoelectric properties.

Answer 10

curie point

Question 11

material attached to the rear of the transducer element to reduce the pulse duration

Answer 11

damping

Question 12

occurs when two waves out of phase with each other create a new wave with amplitude less than the two original waves: out of phase

Answer 12

destructive interference

Question 13

includes both axial and lateral resolution

Answer 13

detail resolution

Question 14

deviation in the direction of the sound eave that is not a result of reflection, scattering, or refraction

Answer 14

diffraction

Question 15

aperture that increases as the focal length increases; minimizes change in the width of the sound beam

Answer 15

dynamic aperture

Question 16

variable receiving focus that follows the changing position of the pulse as it propagates through tissue; the electrical output of the elements can be tined to “listen” in a particular direction and depth

Answer 16

dynamic focusing

Question 17

piezoelectric component of the transducer

Answer 17

element

Question 18

detail resolution located perpendicular to the scan plane; it is equal to the section thickness and is the source of the section thickness artifact

Answer 18

elevation resolution

Question 19

region of the sound beam in which the diameter increases as the distance from the transducer increases

Answer 19

far zone

Question 20

distance from a focused transducer to the center of the focal zone; distance from a focused transducer to the spatial peak intensity

Answer 20

focal length

Question 21

concentration of the sound beam into a smaller area

Answer 21

focal point

Question 22

area or region of the focus

Answer 22

focal zone

Question 23

fraunhofer zone

Answer 23

far zone

Question 24

fresnel zone

Answer 24

near zone

Question 25

additional weak beams emitted from a multi-element transducer that propagates in directions different from the primary beam

Answer 25

grating lobes

Question 26

all points on a wave front or at a source are point of sources for the production of spherical secondary wavelets

Answer 26

huygens principle

Question 27

interference occurring when two waves interact or overlap, resulting in the creation of a new wave

Answer 27

interference phenomenon

Question 28

ability to distinguish two structures lying perpendicular to the sound beam

Answer 28

lateral resolution

Question 29

a ceramic piezoelectric material

Answer 29

lead zirconate titanate (PZT)

Question 30

material attached to the front face of the transducer element to reduce reflections at the transducer surface

Answer 30

matching layer

Question 31

region of the beam between the transducer and focal point, which decreases in size as it approaches the focus

Answer 31

near zone

Question 32

natural frequency of the transducer; it is determined by the propagation speed and thickness of the element in pulse ultrasound and by the electrical frequency in continuous wave

Answer 32

operating frequency

Question 33

conversion of pressure to electric voltage

Answer 33

piezoelectricity

Question 34

applying voltage pulses to all elements in the assembly group, but with minor time differences.

Answer 34

phased

Question 35

operating frequency

Answer 35

resonance frequency

Question 36

operated by applying voltage pulses to a group of elements in succession

Answer 36

sequenced array

Question 37

additional weak beams traveling from a single element transducer in directions different from primary beam

Answer 37

side lobes

Question 38

dividing each element into small pieces to reduce grating lobes

Answer 38

subdicing

Question 39

device that converts energy from one form to another

Answer 39

transducer

Question 40

transducer element, damping, matching layer, and housing; also known as probe, scan head

Answer 40

transducer assembly