Ch. 12 Two-Dimensional Imaging

Question 1

The ________________________ transducer contains a single, circular, disc-shaped active element that is physically moved. This movement creates a scan plane.

Answer 1

The Mechanical transducer contains a single, circular, disc-shaped active element that is physically moved. This movement creates a scan plane.

Question 2

Mechanical transducers can have only ______ active element, the elements shape resembles a coin.

Answer 2

Mechanical transducers can have only one active element, the elements shape resembles a coin.

Question 3

The image created by a mechanical transducer is ______________ or ____________________-shaped, similar to the sweeping of a wiper blade across a car’s windshield.

Answer 3

The image created by a mechanical transducer is fan or sector-shaped similar to the sweeping of a wiper blade across a car’s windshield.

Question 4

When there is a damaged PZT crystal to a mechanical transducer what happens to the image?

Answer 4

The entire image is lost when the crystal malfunctions, because the mechanical transducers have only a single crystal.

Question 5

__________________ contain multiple active elements

Answer 5

arrays contain multiple active elements

Question 6

An array comprises a single slab of PZT cut into a collection of separate pieces called _______.

Answer 6

An array comprises a single slab of PZT cut into a collection of separate pieces called elements

Question 7

A ______________________ is the combination of the active element, wire, and system electronics.

Answer 7

A channel is the combination of the active element, wire, and system electronics.

Question 8

The 3 types of array transducers are: __________________, _________________, and ____________________.

Answer 8

The 3 types of array transducers are

• Linear
• Annular
• Convex

Question 9

A collection of elements in a line (there are two types):

Answer 9

1. Linear Switched (or Sequential) Array
2. Linear Phased Array

Question 10

A group of ringed elements with a common center

Answer 10

Annular Array

Question 11

Elements arranged in an arc. There are two types:

Answer 11

1. Convex Switched (or Sequential) Array
2. Convex Phased Array

[Convex, Curved, Curvilinear]

Question 12

_____________________ Switched/Sequential Arrays have a few elements (5-10) but not all are fired at the exact same time. There is no steering, pulses are sent down parallel lines. Rectangular shaped, no wider than the transducer, and a defective crystal causes dropout from superficial to deep.

Answer 12

Linear Switched/Sequential Arrays have a few elements (5-10) but not all are fired at the exact same time. There is no steering, pulses are sent down parallel lines. Rectangular shaped, no wider than the transducer, and a defective crystal causes dropout from superficial to deep.

Question 13

____________________ Arrays are adjustable focus or multi-focused, and achieved electronically. A collection of electric pulses is delivered to all the transducers elements in various patterns. The patterns focus & steer the ultrasound beam during transmission. Thus, focusing and steering are electronic.

Answer 13

Phased Arrays are adjustable focus or multi-focused, and achieved electronically. A collection of electric pulses is delivered to all the transducers elements in various patterns. The patterns focus & steer the ultrasound beam during transmission Thus, focusing and steering are electronic.

Question 14

__________________________________ transducers have mechanical steering, with a motor that physically moves the ringed-element array so that the sound beams are transmitted in different directions

Answer 14

Annular Phased Array transducers have mechanical steering, with a motor that physically moves the ringed-element array so that the sound beams are transmitted in different directions

Question 15

if there is a defective PZT in an Annular Phased Array it results in a ____________________________ band of dropout

Answer 15

If there is a defective PZT in an Annular Phased Array it results in a horizontal band of dropout

Question 16

For a Sequential / Switched Arrays there is ________________ dropout with a damaged PZT, and there are ____ to ____ elements fired at a time.

Answer 16

For Sequential / Switched Arrays there is verticle dropout with a damaged PZT, and there are 5-10 elements fired at a time.

Question 17

___________________________aka _____________________________ resolution answers the following question: are the reflections on the image created from structures directly in the imaging plane or from structures that lie above or beneath the imaging plane?

Answer 17

Slice Thickness aka Elevational Resolution answers the following question: are the reflections on the image created from structures directly in the imaging plane or from structures that lie above or beneath the imaging plane?

Question 18

A mechanical transducer produces a __________________ image shape image, its steering is ____________________, and its focusing is ____________________

Answer 18

A mechanical transducer produces a sector shaped image, its steering is mechanical, and its focusing is fixed

Question 19

A linear sequential transducer has a _____________________ image shape, a _____________________ steering technique and __________________ focusing

Answer 19

A linear sequential transducer has a rectangular image shape, a electronic steering technique and electronic focusing

Question 20

A phased array has a ____________________ image shape, and _______________________ steering technique, and its focusing is _____________________

Answer 20

A phased array has a sector image shape and electronic steering technique, and its focusing is electronic

Question 21

An Annular phased transducer has a _____________________ image shape, and _________________________ steering technique, and its focusing is ________________

Answer 21

An Annular phased transducer has a sector image shape, and mechanical steering technique, and its focusing is electronic

Question 22

A Convex transducer has a __________________________ image, an ____________________ steering technique, and ________________ focusing

Answer 22

A Convex transducer has a blunted sector image, an electronic steering technique, and electronic focusing

Question 23

A Vector transducer has a ___________________ image shape, an _____________________ steering technique, and _______________________ focusing

Answer 23

A Vector transducer has a trapezoidal image shape, an electronic steering technique, and electronic focusing

Question 24

Reducing strength of side and grating lobes can be achieved through a process called _____________________________

Answer 24

Reducing strength of side and grating lobes can be achieved through a process called Apodization

Question 25

When there is ____________________, a crystal is divided into a group of smaller crystals called sub-elements. These sub-elements are electronically joined, and act as if they are a single crystal, which reduces grating lobes

Answer 25

When there is Subdicing, a crystal is divided into a group of smaller crystals called sub-elements. These sub-elements are electronically joined, and act as if they are a single crystal, which reduces grating lobes