Deck 11: Multislice Computed Tomography: Physical Principles and Instrumentation

Question 1

Volume CT can also be referred to as:

A) spiral CT.
B) circular CT.
C) rounded CT.
D) spherical CT.

Answer 1

spiral CT.

Question 2

New capabilities created as a result of the creation of spiral/helical CT include each of the following applications except:

A) CT endoscopy.
B) real-time CT fluoroscopy.
C) stroke imaging.
D) CT angiography.

Answer 2

stroke imaging.

Question 3

All of these components are rotating parts of the spiral/helical CT scanner except the:

A) X-ray tube.
B) high-voltage generator.
C) detectors.
D) front-end memory.

Answer 3

front-end memory.

Question 4

What is the ideal pitch in spiral/helical CT?

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

Question 5

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 6

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.

Question 7

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 8

Which method of CT scanning does interscan delay occurs?

A) Single-slice CT (SSCT) scanner
B) Slice-by-slice CT scanner
C) Volume CT scanner
D) Multislice CT (MSCT) scanner

Question 9

The CT detector consists of each of these components except:

A) radiation sensor.
B) photodiodes.
C) analog to digital converter (ADC).
D) high-frequency generator.

Question 10

Detector row collimation is equal to:

A) D (mm) + N.
B) D (mm) - N.
C) D (mm) * N.
D) D (mm)/N.

Question 11

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

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

Question 12

The radiation sensors convert ___________ to ___________.

A) light; X-ray photons
B) X-ray photons; light
C) light; electrical signals
D) electric signals; light

Question 13

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

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

Question 14

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 15

The overall goal of MSCT is to:

A) improve volume coverage speed performance.
B) decrease patient dose.
C) improve spatial resolution.
D) increase tube memory.

Question 16

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

A) Collimation
B) Table increment
C) Pitch
D) Couch movement

Question 17

The photodiodes convert _________ into ________.

A) light; X-ray photons
B) X-ray photons; light
C) light; electrical signals
D) electric signals; light

Question 18

Limitations of slice-by-slice sequential CT scanning include each of the following except:

A) longer examination time.
B) inaccurate generation of three-dimensional (3D) images.
C) possible omitted anatomy because of patient respiration.
D) interpolation.

Question 19

Which of the following describes when raw data for image reconstruction can be selected on the basis of the patient's electrocardiogram (ECG)?

A) Cardiac reconstruction
B) Gated reconstruction
C) Motion reconstruction
D) Timed reconstruction

Question 20

All of the following terms are used to refer to MSCT except:

A) multisection CT.
B) multidetector CT.
C) multichannel CT.
D) multisystem CT.

Question 21

Which of the following is not a type of detectors used in MSCT scanners?

A) Hybrid detectors
B) Universal detectors
C) Nonuniform detectors
D) Uniform detectors

Question 22

In MSCT, the slice thickness is not determined by which factor?

A) Volume coverage
B) Beam width in the z-axis
C) Pitch
D) Shape and width of the reconstruction filter

Question 23

What type of detector is used in MSCT scanners?

A) Helium gas detector
B) Solid-state scintillation detector
C) Tungsten detector
D) Xenon gas detector

Question 24

What term is used to describe the resorting of the 3D data collected from the cone-beam acquisition to a set of 2D fan-beam data?

A) Binning
B) Rebinning
C) Reformatting
D) Sampling

Question 25

As the pitch increases, the image quality:

A) increases.
B) decreases.
C) does not change.
D) has no direct relationship.

Question 26

Pitch is directly related to:

A) patient dose.
B) kVp.
C) patient comfort.
D) detector configuration.

Question 27

Which of the following is not considered a cone-beam algorithm?

A) Exact algorithms
B) Approximate algorithms
C) Opposed algorithms
D) Feldkamp-Davis-Kress (FDK) algorithm

Question 28

The operator console controls all of the following except:

A) communication.
B) control of the gantry.
C) patient dose.
D) windowing.

Question 29

All of the following are materials used in solid-state detectors except:

A) calcium tungsten.
B) gadolinium oxysulfide (GOS).
C) gadolinium oxide.
D) yttrium-gadolinium oxide.

Question 30

In an MSCT scanner, what type of algorithm can be used if the number of detector rows is small?

A) Cone-beam reconstruction
B) Fan-beam reconstruction
C) x-axis reconstruction
D) z-axis reconstruction

Question 31

In MSCT, a _________ beam geometry results, rather than a fan beam as in SSCT scanners.

A) circular
B) cone
C) rectangular
D) triangular

Question 32

What term is used to describe the number of data collection channels and the effective section thickness determined by the data acquisition system settings?

A) Detector array
B) Detector configuration
C) Detector geometry
D) Detector set

Question 33

What term is used to describe the separating of the direct and complementary data trails and also results in efficient z-sampling?

A) Efficient sampling scan
B) Complete sampling scan
C) Optimized sampling scan
D) Total sampling scan

Question 34

All of the following are housed in the MSCT gantry except:

A) detectors.
B) detector electronics.
C) collimation selector.
D) X-ray tube.

Question 35

The definition of pitch in a multislice scanner, as defined by the International Electrotechnical Commission, states:

A) P = distance the table travels per rotation (d)/total collimation (W)
B) P = distance the table travels per rotation (d) + total collimation (W)
C) P = distance the table travels per rotation (d) * total collimation (W)
D) P = total collimation (W)/distance the table travels per rotation (d)

Question 36

What is the term used to describe the flipped view used for interpolated reconstruction?

A) Complementary data
B) Opposed data
C) Opposite data
D) Reciprocal data

Question 37

If the X-ray prepatient collimation width is 24 cm and the scanner has a four-row detector array, what is the detector row collimation?

A) 4 mm
B) 5 mm
C) 6 mm
D) 7 mm

Question 38

The computer systems of MSCT scanners have hardware that provides all of the following except:

A) high-speed processing.
B) image communication.
C) image reconstruction.
D) postprocessing operations.

Question 39

In 1992, the first modern multislice scanner was introduced by:

A) Elscint.
B) GE Healthcare Systems.
C) Siemens Healthcare Systems.
D) Toshiba Healthcare Systems.

Question 40

Which of the following is not a physical property of detectors?

A) High luminescence efficiency
B) Large dynamic range
C) Small afterglow
D) Recyclable value

Question 41

All of the following are advantages of MSCT except:

A) increased speed and volume coverage.
B) improved spatial resolution.
C) reduction of radiation exposure.
D) decreased contrast resolution.

Question 42

When the slice thickness is equal to the pixel size, the data acquired are said to be:

A) anisotropic.
B) distropic.
C) isotropic.
D) unitropic.

Question 43

An algorithm common in MSCT scanners is the FDK algorithm.

Question 44

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

Question 45

MSCT scanners utilize xenon gas detectors for their high X-ray absorption.

Question 46

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

Question 47

Which of the following is not a parameter of image quality?

A) Spatial resolution
B) Patient dose
C) Contrast resolution
D) Noise

Question 48

Slice-by-slice sequential CT creates inaccurate generation of 3D images resulting in partial voluming artifacts.

Question 49

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

Question 50

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

Question 51

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

Question 52

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

Question 53

Dual-source CT (DSCT) scanners are primarily used for:

A) cardiac imaging.
B) quantitative imaging.
C) pulmonary imaging.
D) virtual colonoscopy.

Question 54

The first model of the 256-slice 4D CT scanner was developed in:

A)2001.
B)2002.
C)2003.
D)2004.

Question 55

Pitch affects both image quality and patient dose.

Question 56

DSCT scanners require two operator consoles to input each examination's scanning parameters.

Question 57

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

Question 58

Another application of the DSCT scanner includes imaging of obese patients.

Question 59

To prevent anode movement under the stress of subsecond acceleration, new X-ray tubes have the anode mounted on a shaft that extends along the tube.

Question 60

A pitch greater than 1 will result in an increased dose.