Kremkau Ch3

Question 1

Aperture

Answer 1

Size of transducer element (for a single-element transducer) or a group of elements (for an array).

Question 2

Apodization

Answer 2

Nonuniform driving elements in an array to reduce grating lobes.

Question 3

Array

Answer 3

A transducer assembly containing serval piezoelectric elements.

Question 4

Axial resolution

Answer 4

The minimum reflector separation along the sound path that is required to produce separate echoes.

Question 5

Beam

Answer 5

Region containing continuous wave sound; region through which a sound pulse propagates.

Question 6

Composite

Answer 6

Combination of piezoelectric ceramic and non-piezoelectric polymer.

Question 7

Convex array

Answer 7

Curved linear array.

Question 8

Crystal

Answer 8

Element

Question 9

Curie point

Answer 9

Temperature at which element material loses its piezoelectric properties.

Question 10

Damping

Answer 10

Material attached to rear face of a transducer element to reduce pulse duration; the process of pulse duration reduction.

Question 11

Detailed resolution

Answer 11

The ability to image fine detail and to distinguish closely spaced reflectors.

Question 12

Disk

Answer 12

Thin, flat, circular object.

Question 13

Dynamic aperture

Answer 13

Aperture that increases with increasing focal length (to maintain consent focal width).

Question 14

Dynamic focusing

Answer 14

Continuous variable reception focusing that follows the increasing depth of the transmitted pulse as it travels.

Question 15

Element

Answer 15

The piezoelectric component of a transducer assembly.

Question 16

Elevational resolution

Answer 16

The detail resolution in the direction perpendicular to the scan plane. It is equal to the section thickness and is the source of section thickness artifact.

Question 17

Far zone

Answer 17

The region of a sound beam in which the beam diameter increase as the distance from the transducer increases; also called far field.

Question 18

Focal length

Answer 18

Distance from the focused transducer to the center of the focal region or to location of the spatial peak intensity.

Question 19

Focal region

Answer 19

region of minimum beam diameter and area.

Question 20

Focal zone

Answer 20

Length of the focal region.

Question 21

Focus

Answer 21

The concentration of the sound beam into a smaller beam area than would exist otherwise.

Question 22

Grating lobes

Answer 22

Additional weaker beams of sound traveling out in directions different from the primary beam as a result of the multi-element structure of transducer arrays.

Question 23

Lateral

Answer 23

Perpendicular to the direction of sound travel.

Question 24

Lateral resolution

Answer 24

Minimum reflector separation perpendicular to the sound path that is required to produce separate echoes.

Question 25

Lead zirconate titanate

Answer 25

A ceramic piezoelectric material. (PZT)

Question 26

Lens

Answer 26

A curved material that focuses a sound or light beam.

Question 27

Linear

Answer 27

Adjective form of line.

Question 28

Linear arry

Answer 28

Array made of rectangular elements arranged in a straight line.

Question 29

Linear phased array

Answer 29

Linear array operated by applying voltage pulses to all elements, but with small time differences to direct ultrasound pulses out in various directions.

Question 30

Linear sequenced array

Answer 30

linear array operated by allying voltage pulses to groups of elements sequentially.

Question 31

Matching layer

Answer 31

Material attached to the front face of the transducer element to reduce the reflections at the transduce surface.

Question 32

Natural focus

Answer 32

The narrowing of sound beam that occurs with an unfocused flat transducer element.

Question 33

Near zone

Answer 33

The region of a sound beam in which the beam diameter decrease as the distance from the transducer increases; AKA near field.

Question 34

Operating frequency

Answer 34

Preferred frequency of operation of a transducer. (maximum efficiency)

Question 35

Phased array

Answer 35

An array that steers and focuses the beam electronically (with short time delays).

Question 36

Phased linear array

Answer 36

Linear sequenced array with phased focusing added; linear sequenced array with phased steering of pulses to produce a parallelogram-shaped display.

Question 37

Piezoelectricity array

Answer 37

Conversion of pressure to electric voltage.

Question 38

Probe

Answer 38

Transducer assembly

Question 39

Resolution

Answer 39

The ability to distinguish echoes in terms of space, time, or strength (called detail, temporal, and contrast resolutions, respectively).

Question 40

Resonance frequency

Answer 40

Operating frequency

Question 41

Scanhead

Answer 41

transducer assembly

Question 42

Sector

Answer 42

A geometric figure by two radii and the arc of the circle included between them.

Question 43

Sensitivity

Answer 43

Ability of an imaging system to detect weak echoes.

Question 44

Side lobes

Answer 44

Weaker beams of sound traveling out from a single element in directions different from those of the primary beam.

Question 45

Sound beam

Answer 45

The region of a medium that contains virtually all the sound produced by the transducer.

Question 46

Source

Answer 46

An emitter of ultrasound; transducer.

Question 47

Transducer

Answer 47

A device that converts energy to one form to another.

Question 48

Transducer assembly

Answer 48

transducer element with damping and matching materials assembled in a case.

Question 49

Ultrasound transducer

Answer 49

A device that converts electric energy to ultrasound energy, and vice versa.

Question 50

Vector array

Answer 50

Linear sequenced array that emits pulses from different starting points and in different directions.

Question 51

Axial

Answer 51

In the direction of the transducer axis (Sound travel direction).