Deck 11: Single-Slice Spiralhelical Computed Tomography: Physical Principles and Instrumentation

Question 1

Which of the following can eliminate motion artifacts? I. calculation of a planar data set
II) increased scan speed
III) reconstruction of images

A)I and II
B)II and III
C)I and III
D)I, II, and III

Answer 1

I and III

Question 2

All of the following are requirements for volume scanning except:

A)continuous couch movement
B)increased cooling capacity
C)slip-ring technology
D)tube memory

Answer 2

tube memory

Question 3

The stationary part of the spiral/helical computed tomography scanner consists of: I. front-end memory and computer
II) detector electronics
III) first-stage high-voltage component

A)I and II
B)II and III
C)I and III
D)I, II, and III

Answer 3

I and III

Question 4

The time it takes to accomplish steps 1, 3, and 4 in the scanning sequence for a conventional computed tomography scanner is called the:

A)intergroup delay time
B)interscan delay time
C)data acquisition time
D)scan speed time

Question 5

The x-ray tube and detectors are able to rotate continuously during data collection as a result of slip-ring technology.

Question 6

Limitations of slice-by-slice sequential computed tomography scanning include: I. longer examination time
II) inaccurate generation of three-dimensional images
III) possible omitted anatomy because of patient respiration

A)I and II
B)II and III
C)I and III
D)I, II, and III

Question 7

What year was the first computed tomography scanner able to perform volume data acquisition introduced?

A)1988
B)1989
C)1990
D)1991

Question 8

The first step in volume scanning is analog to digital conversion.

Question 9

The ideal pitch in spiral/helical computed tomography is 2:1.

Question 10

Even with slip-ring technology, long high-tension cables are needed for data transfer.

Question 11

Pitch affects both image quality and patient dose.

Question 12

The rotating part of the spiral/helical computed tomography scanner consists of: I. x-ray tube
II) high-voltage generator
III) detectors

A)I and II
B)II and III
C)I and III
D)I, II, and III

Question 13

What allows the x-ray tube to continuously rotate so that a volume of the patient can be acquired?

A)detector electronics
B)long high-tension cables
C)slip rings
D)tube electronics

Question 14

The overall goal of single-slice spiral/helical volume computed tomography is to increase the volume coverage speed compared with that of the conventional computed tomography scanner.

Question 15

Table increment and pitch are directly proportional.

Question 16

Comparison studies have shown that the dose in conventional computed tomography is about equal to that of spiral/helical computed tomography.

Question 17

Volume computed tomography can also be referred to as: I. spiral computed tomography
II) helical computed tomography
III) circular computed tomography

A)I and II
B)II and III
C)I and III
D)I, II, and III

Question 18

All the following are problems that can occur from data acquisition with spiral geometry except:

A)localization of a particular slice is difficult
B)inconsistent projection data
C)increased patient dose
D)streak artifacts can occur

Question 19

An early pioneer in the development of the technique of volume rendering was Dr. Willi
A.Kalender.

Question 20

A number of interpolation algorithms are used to produce the planar data set, but linear interpolation is the simplest approach.

Question 21

All of the following affect noise in spiral/helical computed tomography except:

A)beam intensity
B)beam quality
C)detector cell size
D)matrix size

Question 22

The pitch ratio is expressed as:

A)distance the table travels during 360 degrees/slice thickness
B)slice thickness/distance the table travels during 360 degrees
C)slice thickness + distance the table travels during 360 degrees
D)slice thickness * distance the table travels during 360 degrees

Question 23

What is the ideal pitch in spiral/helical computed tomography?

A)1
B)2
C)3
D)4

Question 24

Which of the following are reasons that patient dose is less in single-slice spiral/helical computed tomography compared with conventional computed tomography? I. tube currents are set to lower values
II) spiral/helical computed tomography largely eliminates the need to retake single scans
III) spiral/helical computed tomography can use a pitch of less than 1

A)I and II
B)II and III
C)I and III
D)I, II, and III

Question 25

The reconstruction increment is also referred to as: I. the reconstruction interval
II) reconstruction spacing
III) the reconstruction model

A)I and II
B)II and III
C)I and III
D)I, II, and III

Question 26

Volume coverage for fixed scan time and fixed slice thickness can be expressed as:

A)volume coverage = pitch + beam collimation
B)volume coverage = pitch - beam collimation
C)volume coverage = beam collimation * scan time
D)volume coverage = scan time - beam collimation

Question 27

New capabilities created as a result of the creation of spiral/helical computed tomography include: I. real-time computed tomography fluoroscopy
II) computed tomography angiography
III) computed tomography endoscopy

A)I and II
B)II and III
C)I and III
D)I, II, and III

Question 28

All the following are typical scan parameters for spiral/helical computed tomography scanners except:

A)table speed
B)scan range
C)number of revolutions
D)patient size

Question 29

What is defined as the distance (in millimeters) that the computed tomography table moves during one revolution of the x-ray tube?

A)collimation
B)table increment
C)pitch
D)couch movement

Question 30

What term describes how thick a section is imaged and to what extent details within the section contribute to the signal?

A)detector profile
B)collimation profile
C)data acquisition profile
D)slice sensitivity profile