Transducers and Beams

Question 1

size of the source

Answer 1

Aperture

Question 2

A method for reducing side lobes (lateral array elements) in some arrays. It gradually decreases the vibration of the transducer surface with distance from its center by improving the directivity.

Answer 2

Apodization

Question 3

A collection of active elements within a transducer housing

Answer 3

Array

Question 4

Perpendicular to scan plane

Answer 4

Axial

Question 5

The minimum distance 2 structures are separated from front to back or anterior to posterior, and still be distinguished as separate by the ultrasound machine

Answer 5

Axial Resolution

Question 6

width of the pulse as it travels away from the transducer

Answer 6

Beam

Question 7

Man Made-improves bandwidth, sensitivity, resolution elements

Answer 7

Composite

Question 8

Crystals arranged in an arc; sector shape format

Answer 8

Convex array

Question 9

Natural materials: Quartz, Rochelle salts, tourmaline

Man-made: Lead zirconate titanate or PZT barium titanate, lead metaniobate, lead titanate

Answer 9

Crystal

Question 10

Transducer crystals lose their piezoelectric properties if they are heated above a critical temperature

Answer 10

Curie point

Question 11

Material bonded to the back of the active element; limits “ringing” of the crystal; shortens pulse duration and spatial pulse length, therefore improving image quality

Answer 11

Damping

Question 12

the machine’s ability to see and differentiate small structures and represent them (anatomically) correctly on the ultrasound image

Answer 12

Detail resolution

Question 13

continually changing focus

Answer 13

Dynamic focusing

Question 14

piezoelectric element, active element, or crystal

Answer 14

Element

Question 15

Slice thickness resolution

Answer 15

Elevational resolution

Question 16

Place where the beam begins to diverge (Fraunhofer zone)

Answer 16

Far zone

Question 17

the distance from the transducer face to the focus

Answer 17

Focal length

Question 18

Focus Near Zone Focal Length (focal depth, near zone length) Far Zone Focal zone

Answer 18

Focal region

Question 19

the area of highest, most uniform beam intensity

Answer 19

Focal zone

Question 20

improve resolution at given depth

Answer 20

Focus

Question 21

unwanted parts of the ultrasound beam emitted off axis that produce image artifacts due to error in positioning the returning echo.

Answer 21

Grating lobes

Question 22

Scan plane width or beam diameter

Answer 22

Lateral

Question 23

The minimum distance that two side by side structures can be separated and still show 2 separate echoes on the screen.

Answer 23

Lateral resolution

Question 24

one of the world’s most widely used piezoelectric ceramic materials (man made)

Answer 24

Lead zirconate titanate

Question 25

external focusing

Answer 25

Lens

Question 26

Arranged in or extending along a straight or nearly straight line

Answer 26

Linear

Question 27

parallel scan line, width & length of image are approximately equal for superficial structures

Answer 27

Linear array

Question 28

Beam steering and focusing is electronic | Phased array or electronic sector

Answer 28

Linear phased array

Question 29

no fixed focus , with rectangle image, sequencing beams large acoustic footprint

Answer 29

Linear sequenced array

Question 30

Reduces reflections at transducer - tissue interface | Also called impedance matching layer

Answer 30

Matching layer

Question 31

transition point between the near field and the far field of a non focused transducer

Answer 31

Natural focus

Question 32

Region between the transducer and the focus | Also called the Fresnel zone

Answer 32

Near zone

Question 33

Resonant Frequency or natural frequency depends on thickness of the crystal, and Speed of sound in the crystal

Answer 33

Operating frequency

Question 34

adjustable, multi-focus

Answer 34

Phased array

Question 35

phased focus control is applied to a linear sequenced array.

Answer 35

Phased linear array

Question 36

electricity or electric polarity due to pressure especially in a crystalline substance

Answer 36

Piezoelectricity

Question 37

to search into or examine thoroughly

Answer 37

Probe

Question 38

the machine’s ability to image structures with accuracy

Answer 38

Resolution

Question 39

The operating frequency of a transducer

Answer 39

Resonance frequency

Question 40

pie shaped image

Answer 40

Sector

Question 41

some of the energy from transducer radiates at various angles to the transducer face

Answer 41

Side lobes

Question 42

any device that converts one form of energy into another

Answer 42

Transducer

Question 43

Combination of phased array electronics and linear sequential array probes to provide electronic steering and multiple focal zones

Answer 43

Vector array