Deck 4: Data Acquisition Concepts

Question 1

Which scanner allows for continuous rotation of the X-ray tube while the patient moves simultaneously through the gantry aperture?

A) Third-generation conventional scanner
B) Fourth-generation conventional scanner
C) Spiral/helical scanner
D) Dynamic volume scanner

Answer 1

Spiral/helical scanner

Question 2

CT detectors generate a signal that represents the attenuation as the ray moves across the slice. This signal is called:

A) a view sample.
B) an acquisition sample.
C) a profile.
D) a data sample.

Answer 2

a profile.

Question 3

Which X-ray generator is used in modern CT scanners?

A) Single-phase half-wave rectified
B) Single-phase full-wave rectified
C) High-frequency generator
D) Three-phase, six-pulse generator

Answer 3

High-frequency generator

Question 4

Compared with conventional CT scanners, slip-ring scanners offer all of the following advantages except:

A) removal of cable wraparound.
B) elimination of start-stop action.
C) capacity for interrupted acquisition protocols.
D) minimal interscan delays.

Question 5

Which CT scanner is based on a fan-beam geometry and complete rotation of the X-ray tube and detectors?

A) First-generation scanner
B) Second-generation scanner
C) Third-generation scanner
D) Fourth-generation scanner

Question 6

A single ray in computed tomography (CT) is:

A) a beam of X-rays emanating from the X-ray tube.
B) a single straight line path of an X-ray beam.
C) the total attenuation as measured by the detector.
D) a collection of beams gathered by the detector.

Question 7

Which generation of scanners, also called dual-source CT scanners, consists of two X-ray tubes and two sets of detectors?

A) Third generation
B) Fourth generation
C) Fifth generation
D) Sixth generation

Question 8

In which scanner is the apex of the fan beam located outside the detector?

A) Third-generation scanner
B) Fourth-generation scanner
C) Fifth-generation scanner
D) Sixth-generation scanner

Question 9

Which of the following is classified as a high-speed CT scanner?

A) Third-generation scanner
B) Fourth-generation scanner
C) Spiral/helical CT scanner
D) Fifth-generation CT scanner

Question 10

Which scanner is based on slip-ring technology?

A) Third-generation conventional scanner
B) Fourth-generation conventional scanner
C) Spiral/helical scanner
D) Fifth-generation scanner

Question 11

The scanner that uses an electron gun to "shoot" electrons toward a target ring is the:

A) fifth-generation scanner.
B) fourth-generation scanner.
C) third-generation scanner.
D) spiral/helical scanner.

Question 12

In one type of fourth-generation CT scanner, the tilting action of the detector ring is referred to as:

A) slip-ring technology.
B) nutating.
C) spiral scanning.
D) helical scanning.

Question 13

Fourth-generation CT scanners are characterized by:

A) rotate-translate motion and parallel beam geometry.
B) rotate-translate motion and fan-beam geometry.
C) fan-beam geometry and continuous rotation of X-ray tube and detectors
D) fan-beam geometry and complete rotation of X-ray tube around a stationary ring of detectors

Question 14

Which of the following X-ray tubes is most likely used in spiral/helical CT scanners?

A) A tungsten target fixed anode tube
B) A tungsten target rotating anode tube
C) A molybdenum target rotating anode tube
D) A rotating anode tube with a rhenium tungsten disk

Question 15

Which of the following refers to the size, shape, motion, and path traced by the X-ray beam as it scans the patient?

A) Beam geometry
B) Projection profile
C) Data acquisition
D) Detector tracing

Question 16

Electromechanical devices made up of rings and brushes to transmit electrical energy across a rotating interface are called:

A) target rings.
B) slip rings.
C) spiral rings.
D) helical rings.

Question 17

A view in CT is:

A) a specific way in which the patient is positioned with respect to the detectors.
B) the total attenuation as measured by the detector.
C) a collection of rays for one translation across the object.
D) a single straight line path of an X-ray beam.

Question 18

The total number of data samples per scan or per slice in CT is the:

A) number of data samples per view times the number of views.
B) number of views.
C) number of detectors plus the number of data samples per detector.
D) number of data samples per view plus the number of views.

Question 19

Which of the following refers to a method by which the patient is systematically scanned by the X-ray tube and detectors to collect enough information for image reconstruction?

A) Beam geometry
B) Data acquisition
C) Sampling
D) Projection reconstruction

Question 20

Which scanner results in a volume of the patient being scanned during a single breath-hold (rather than a single slice of tissue)?

A) Spiral/helical scanner
B) Seventh-generation scanner
C) Second-generation scanner
D) First-generation scanner

Question 21

Which of the following methods does not affect sampling information?

A) Closely packed detectors
B) Milliamperage-seconds (mAs)
C) Slice thickness
D) Double-dynamic focus

Question 22

Which of the following is commonly used in gas-ionization CT detectors?

A) Xenon
B) Oxygen
C) Neon
D) Helium

Question 23

What detector innovation allows for acquisition of both low and high energies for every exposure in CT imaging?

A) Stellar detector
B) Third-generation detector
C) Photon counting detector
D) Dual-layer detector

Question 24

What provides doubling sampling by obtaining two overlapping slices for each detector row per 360-degree rotation?

A) z-flying focal spot technique
B) Double-dynamic focus
C) Quarter-shifted detection
D) Aliasing method

Question 25

The following crystals have been used in scintillation CT detectors except:

A) bismuth germinate.
B) calcium tungstate.
C) calcium fluoride.
D) sodium iodide (NaI).

Question 26

Photodiodes are now used in CT scintillation detectors.

Question 27

Which of the following refers to the ability of the CT detector to capture, absorb, and convert X-ray photons into electrical energy?

A) Efficiency
B) Stability
C) Response time
D) Dynamic range

Question 28

The data acquisition system (DAS) performs each of the following functions except:

A) measures the transmitted radiation beam.
B) encodes these measurements into binary data.
C) powers the rotating components of the gantry.
D) transmits the binary data to the computer.

Question 29

The speed with which a CT detector can detect an X-ray event and recover to detect another event is the:

A) response time.
B) stability.
C) efficiency.
D) dynamic range.

Question 30

The ratio of the largest signal to the smallest signal measured by a CT detector is the:

A) response time.
B) dynamic range.
C) efficiency.
D) stability.

Question 31

The purpose of collimation in CT is each of the following except:

A) create an homogenous beam.
B) to protect the patient.
C) to ensure a constant beam width at the detector.
D) to reduce scatter radiation.

Question 32

The slice thickness in CT is determined by the:

A) focal spot.
B) anode.
C) collimator height.
D) collimator width.

Question 33

All of the following are radiation beams produced by an X-ray tube designed for CT except:

A) homogeneous beam.
B) heterogeneous beam.
C) polychromatic beam.
D) polyenergetic beam.

Question 34

What category of multirow detector array utilizes an isotropic design?

A) Adaptive array detectors
B) Matrix array detectors
C) Unilateral array detectors
D) Identical array detectors

Question 35

Gas-ionization CT detectors convert X-ray photons into electrical signals with no light conversion process in-between.

Question 36

Which detector characteristic refers to the steadiness of the detector response?

A) Efficiency
B) Stability
C) Response time
D) Dynamic range

Question 37

What style of filter is common in CT filtration because it compensates for the difference in beam path length through the axial plane of the object such that a more uniform fluence can be delivered to the detector?

A) Straight filter
B) Bowtie filter
C) Cone filter
D) Star filter

Question 38

What design of collimation is influenced by the size of the focal spot?

A) Prepatient collimation
B) Postpatient collimation
C) Predetector collimation
D) Postdetector collimation

Question 39

The main purpose of a filter used in CT is to:

A) reduce the intensity of the beam at the detector.
B) make the beam less uniform at the detector.
C) decrease the mean energy at the detector.
D) protect the patient.

Question 40

Scintillation detectors convert X-ray photons to light and subsequently to electrical signals.

Question 41

Afterglow refers to the persistence of the image even after the radiation has been turned off.

Question 42

Adaptive section collimation is a design to overcome overscanning, an issue of exposing the patient outside the imaged range which occurs for spiral CT with multirow detectors at the start and the end of the scan.

Question 43

Please match the following data acquisition concepts. All answer selections will be used just once.

Ionization detector

A)Data acquisition system
B)Flashes of light
C)Beam hardening
D)Xenon gas
E)Slice thickness
F)Photodiode
G)Continuous gantry rotation

Question 44

Multirow CT detectors fall into two categories, namely, matrix array detectors and pixel array detectors.

Question 45

The change of attenuation and thickness data into transmission measurement is called efficiency conversion.

Question 46

Please match the following data acquisition concepts. All answer selections will be used just once.

Scintillation

A)Data acquisition system
B)Flashes of light
C)Beam hardening
D)Xenon gas
E)Slice thickness
F)Photodiode
G)Continuous gantry rotation

Question 47

Seventh-generation scanners use flat-panel digital area detectors.

Question 48

Contactless slip-ring design uses a conductive wire as its sliding contact.

Question 49

Optoelectronics refers to the use of lens and light diodes to facilitate data transmission.

Question 50

Gas-ionization detectors are prone to afterglow problems.

Question 51

Sixth-generation scanners are referred to as the cine CT scanner because of its high-speed acquisition for imaging the heart and circulation.

Question 52

The configuration of the dual-row detector system results in faster volume coverage compared with single-row CT systems.

Question 53

Streaking artifacts are the result of too many samples being measured by the detectors.

Question 54

Gas-ionization chambers were first introduced in second-generation scanners.

Question 55

The overall goal of the electron-beam CT (EBCT) scanner is to produce low-resolution images of moving organs that are free of artifacts caused by motion.

Question 56

First-generation scanners were first to use fan-beam geometry.

Question 57

High-frequency generators use a low-frequency inverter circuit to convert the low-voltage current from the main power supply to the high-voltage current required by the CT X-ray tube.

Question 58

The Straton X-ray tube was designed by Toshiba Medical Systems.

Question 59

Anistrophic is a term used to describe detector channels that are equal in size.

Question 60

The high-voltage generators of slip-ring scanners are located in the gantry.

Question 61

Please match the following data acquisition concepts. All answer selections will be used just once.

Filtration

A)Data acquisition system
B)Flashes of light
C)Beam hardening
D)Xenon gas
E)Slice thickness
F)Photodiode
G)Continuous gantry rotation

Question 62

Please match the following data acquisition concepts. All answer selections will be used just once.

Slip-ring design

A)Data acquisition system
B)Flashes of light
C)Beam hardening
D)Xenon gas
E)Slice thickness
F)Photodiode
G)Continuous gantry rotation

Question 63

Please match the following data acquisition concepts. All answer selections will be used just once.

Detector electronics

A)Data acquisition system
B)Flashes of light
C)Beam hardening
D)Xenon gas
E)Slice thickness
F)Photodiode
G)Continuous gantry rotation

Question 64

Please match the following data acquisition concepts. All answer selections will be used just once.

Semiconductor

A)Data acquisition system
B)Flashes of light
C)Beam hardening
D)Xenon gas
E)Slice thickness
F)Photodiode
G)Continuous gantry rotation

Question 65

Please match the following data acquisition concepts. All answer selections will be used just once.

Collimation

A)Data acquisition system
B)Flashes of light
C)Beam hardening
D)Xenon gas
E)Slice thickness
F)Photodiode
G)Continuous gantry rotation