Deck 17: Computed Tomography

Question 1

Spiral scanning collects data for

A) one slice at a time
B) 5-10 slices at a time
C) the entire volume of tissue being imaged
D) none of these

Answer 1

the entire volume of tissue being imaged

Question 2

Slices of anatomy that go from head to foot are

A) coronal
B) sagittal
C) transverse (axial)
D) linear

Answer 2

transverse (axial)

Question 3

The device that absorbs the radiation and produces an electrical signal is the

A) generation
B) gantry
C) detector
D) data acquisition system (DAS)

Answer 3

detector

Question 4

This translate-rotate scanner used a single detector

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

Question 5

This CT scanner took approximately 30 seconds to produce a single image.

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

Question 6

This scanner uses a wide fan beam and a fixed array of detectors that encircle the patient.

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

Question 7

The CT x-ray tube and detector array are found in the

A) central processing unit
B) gantry
C) detector
D) data acquisition system (DAS)

Question 8

The individual credited with inventing the CT scanner is

A) Thomas Edison
B) Wilhelm Roentgen
C) Marie Curie
D) Godfrey Hounsfield

Question 9

Each major development in beam and detector geometry is called a

A) generation
B) gantry
C) detector
D) upgrade

Question 10

Computed tomography was introduced in the

A) 1950s
B) 1960s
C) 1970s
D) 1980s

Question 11

Slices of anatomy that are reformatted to go from side to side are

A) coronal
B) sagittal
C) axial
D) linear

Question 12

Using a detector array with multiple rows allows this type of scanning.

A) Spiral CT
B) Multislice CT
C) Slip-ring technology
D) Cone beam

Question 13

This translate-rotate scanner used approximately 30 detectors and a narrow fan beam.

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

Question 14

This CT scanner took approximately 5 minutes to produce a single image.

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

Question 15

Electron-beam computed tomography (EBCT) was developed to be fast enough to image the

A) lungs
B) heart
C) diaphragm
D) skull

Question 16

This scanner uses a wide fan beam and a rotating array of detectors.

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

Question 17

Most modern CT scanners are based on _______________________ technology.

A) first generation
B) second generation
C) third generation
D) fourth generation

Question 18

Slices of anatomy that are reformatted to go from front to back are

A) coronal
B) sagittal
C) axial
D) posterior

Question 19

This is the only generation of CT scanners that used parallel-beam geometry.

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

Question 20

This advancement has the tube rotating inside the gantry while the patient and table move through the gantry in a continuous motion.

A) Spiral CT
B) Multislice CT
C) Slip-ring technology
D) Cone beam

Question 21

The collimator that controls how much of the detector is exposed is the

A) prepatient collimator
B) postpatient collimator
C) bowtie filter
D) prepatient collimator and postpatient collimator

Question 22

Which of the following is true concerning dual source CT units?

A) Dual source CT units contain two sets of tube-detector pairs.
B) Dual source CT units have quicker scan time.
C) Dual source CT units require less patient dose due to their design.
D) Dual source CT units have better ability to differentiate between tissues than standard MSCT.
E) All of these.

Question 23

The collimator found between the patient and the detectors is the

A) prepatient collimator
B) postpatient collimator
C) bowtie filter
D) prepatient collimator and postpatient collimator

Question 24

The collimator that improves image contrast by limiting the amount of scatter radiation that reaches the detector is the

A) prepatient collimator
B) postpatient collimator
C) prepatient collimator and postpatient collimator
D) none of these

Question 25

The collimator that limits the patient's radiation exposure is the

A) prepatient collimator
B) postpatient collimator
C) bow tie filter
D) prepatient collimator and postpatient collimator

Question 26

The x-ray tube used in CT systems has a larger-diameter anode because

A) larger images are created with CT
B) the tube is bigger and the anode is proportional
C) CT studies produce enormous amounts of heat
D) it improves spatial resolution

Question 27

For CT, the filter placed between the tube and patient is shaped like a

A) hat
B) bowtie
C) fish
D) necktie

Question 28

The Z axis for CT scanning goes from

A) side to side
B) head to foot
C) back to front
D) none of these

Question 29

The high-frequency generator used in CT scanning has minimal voltage ripple, allowing

A) higher kVp to be used
B) higher mA to be used
C) longer exposures
D) more consistent energy x-ray photons

Question 30

The transmission value for a single detector is a

A) view
B) ray
C) profile
D) all of these

Question 31

For single-slice CT, this collimator controls the slice thickness

A) prepatient collimator
B) postpatient collimator
C) bowtie filter
D) prepatient collimator and postpatient collimator

Question 32

The snapshot of all the transmission measurements at a specific location is the

A) view
B) ray
C) profile
D) all of these

Question 33

The composite electrical signal based on transmission values is the

A) view
B) ray
C) profile
D) all of these

Question 34

The CT gantry houses the

A) x-ray tube
B) detector array
C) collimators
D) data acquisition system (DAS)
E) all of these

Question 35

With multislice CT, additional rows of detectors are added along the

A) W-axis
B) X-axis
C) Y-axis
D) Z-axis

Question 36

This collimator is located between the tube and the patient

A) Prepatient collimator
B) Postpatient collimator
C) Bowtie filter
D) Prepatient collimator and postpatient collimator

Question 37

As a result of using multiple rows of detectors, the x-ray beam becomes wider to accommodate for the divergence of the x-rays and is called

A) spiral CT
B) multislice CT
C) slip-ring technology
D) cone beam

Question 38

Another name for the CT table is the

A) gurney
B) couch
C) board
D) stretcher

Question 39

DAS stands for

A) digital absorption system
B) data acquisition system
C) diode acquisition system
D) data absorption system

Question 40

What is the relationship between the number of detector rows in MSCT and radiation dose?

A) direct
B) direct proportional;
C) inverse
D) inverse proportional

Question 41

Which of the following data needs to be known to perform an attenuation calculation?
1) Thickness of the part
2) Original x-ray beam intensity
3) The intensity of the transmitted radiation (as measured by the detector)

A) thickness of the part and original x-ray beam intensity only
B) thickness of the part and the intensity of the transmitted radiation (as measured by the detector) only
C) original x-ray beam intensity and the intensity of the transmitted radiation (as measured by the detector) only
D) thickness of the part, original x-ray beam intensity, and the intensity of the transmitted radiation (as measured by the detector)

Question 42

A tissue that attenuates more x-rays than water has a CT number

A) 0
B) greater than 0
C) less than 0
D) unable to determine unless more is known

Question 43

This is calculated by knowing the dimensions of the pixel and the slice thickness

A) Matrix
B) Pixel
C) Voxel
D) Voxel volume

Question 44

The DAS will

A) strengthen the electrical signal
B) convert the signal to logarithmic information
C) digitize the signal
D) all of these

Question 45

The sequence of computer operations for accomplishing a specific task, such as reconstruction is a(n)

A) array processor
B) algorithm
C) filtered back projection
D) image data

Question 46

The matrix of CT numbers is the

A) array processor
B) algorithm
C) filtered back projection
D) image data

Question 47

The raw data is the

A) measure of the radiation detected
B) measure of the primary radiation
C) digitized linear attenuation coefficient values
D) none of these

Question 48

A tissue that attenuates fewer x-rays than water has a CT number

A) 0
B) greater than 0
C) less than 0
D) unable to determine unless more is known

Question 49

Filtered back projection is used to:
1) analyze the raw data for one slice
2) assess image quality for multiple slices
3) to determine the µ of each voxel

A) analyze the raw data for one slice and assess image quality for multiple slices only
B) analyze the raw data for one slice and to determine the µ of each voxel only
C) assess image quality for multiple slices and to determine the µ of each voxel only
D) analyze the raw data for one slice, assess image quality for multiple slices, and to determine the µ of each voxel

Question 50

The number of rows and columns that make up the digital image is the

A) matrix
B) pixel
C) voxel
D) voxel volume

Question 51

This is the most common reconstruction algorithm used in CT.

A) Array processor
B) Algorithm
C) Filtered back projection
D) Image data

Question 52

The DAS is located

A) just below the couch
B) inside the x-ray tube
C) within the gantry
D) in the central processing unit

Question 53

The CT number of water is

A) 0
B) greater than 0
C) less than 0
D) unable to determine unless more is known

Question 54

The component of the computer dedicated to performing the enormous number of calculations necessary for CT is the

A) array processor
B) algorithm
C) filtered back projection
D) image data

Question 55

Based on the Hounsfield scale, the CT number of air is

A) -1000
B) 0
C) 1000
D) None of these

Question 56

The smallest component of the matrix is the

A) matrix
B) pixel
C) voxel
D) voxel volume

Question 57

The small amount of tissue represented by a pixel is the

A) matrix
B) pixel
C) voxel
D) voxel volume

Question 58

Which of the following is true concerning adaptive statistical iterative reconstruction (ASIR)?

A) ASIR is a reconstruction technique that starts reconstruction after a first-pass FBP reconstruction
B) ASIR techniques shorten reconstruction time while maintaining much lower image noise than if the same raw data were reconstructed with FBP alone
C) ASIR reduces quantum noise substantially with no impact on spatial or contrast resolution
D) All of these

Question 59

The image matrix for CT is __________ than the image matrix for digital radiography.

A) smaller
B) larger
C) the same as

Question 60

A CT image typically has a ________________ matrix

A) 64* 64
B) 128 *128
C) 256 * 256
D) 512 * 512

Question 61

The midpoint of the range of CT numbers to be displayed in the image is the

A) window level
B) window height
C) window width
D) window clearance

Question 62

The area of anatomy seen on the monitor is the

A) protocol
B) scan field of view (SFOV)
C) display field of view (DFOV)
D) pitch

Question 63

An image with a WW of 200 and a WL of 50 produces an image that displays pixels with CT numbers ranging from

A) -100 to 100
B) -50 to 100
C) -50 to 150
D) 200 to 250

Question 64

A pitch of 1 indicates that with each rotation of the tube

A) the table is moving farther than the slice thickness
B) the table is moving less than the slice thickness
C) the table is moving the same distance as the slice thickness
D) none of these

Question 65

This refers to all the settings that must be determined for a CT imaging study

A) Protocol
B) SFOV
C) DFOV
D) Pitch

Question 66

Pitch ranges from

A) 0 to 5
B) 0.5 to 2
C) 1 to 5
D) 2 to 4

Question 67

Overlapping slices occur with a

A) pitch of 0
B) pitch of 0.5
C) pitch of 1
D) pitch of 2

Question 68

With spiral CT imaging, the relationship between slice thickness and table travel during one tube rotation is the

A) protocol
B) scan field of view (SFOV)
C) display field of view (DFOV)
D) pitch

Question 69

The actual anatomy being imaged for the CT study is determined by the

A) protocol
B) scan field of view (SFOV)
C) display field of view (DFOV)
D) pitch

Question 70

Based on the Hounsfield scale, the CT number of bone is approximately

A) -1000
B) 0
C) 1000
D) None of these

Question 71

Determining the CT numbers that will be visible in the image is

A) annotation
B) windowing
C) region of interest (ROI)
D) multiplanar reformation (MPR)

Question 72

The range of CT numbers visible in the CT image is determined by the

A) window level
B) window height
C) window width
D) window clearance

Question 73

How will a pixel with a CT number of -250 appear if the WW is 600 and the WL is -300?

A) Black
B) White
C) Gray
D) It is impossible to say

Question 74

The image data is the

A) linear attenuation coefficients
B) matrix of CT numbers
C) same as the raw data
D) none of these

Question 75

How will a pixel with a CT number of 250 appear if the WW is 200 and the WL is 50?

A) Black
B) White
C) Gray
D) It is impossible to say

Question 76

The process that allows image data to be displayed in coronal or sagittal planes is

A) annotation
B) windowing
C) region of interest (ROI)
D) multiplanar reformation (MPR)

Question 77

An image with a WW of 600 and a WL of -300 produces an image that displays pixels with CT numbers ranging from

A) -300 to 600
B) -600 to 0
C) -300 to 300
D) -100 to -300

Question 78

This specific area of the image is often selected to perform data analysis

A) Annotation
B) Windowing
C) Region of interest (ROI)
D) Multiplanar reformation (MPR)

Question 79

Adding a printed comment or label to the image is

A) annotation
B) windowing
C) ROI
D) MPR

Question 80

A pitch of 2 indicates that with each rotation of the tube

A) the table is moving farther than the slice thickness
B) the table is moving less than the slice thickness
C) the table is moving the same distance as the slice thickness
D) none of these