Question 1

An array of numbers arranged in a grid of rows and columns is called a:

Accepted Answer

A)  pixel. 
B)  voxel. 
C)  matrix. 
D)  scan profile. 
A)  pixel. 
B)  voxel. 
C)  matrix. 
D)  scan profile. C

Question 2

Which generation of CT scanners uses a dual-energy source (two x-ray tubes)?

Accepted Answer

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

Question 3

The most significant geometric factor that contributes to spatial resolution is:

Accepted Answer

A)  detector aperture width. 
B)  FOV. 
C)  slice thickness. 
D)  x-ray beam energy. 
A)  detector aperture width. 
B)  FOV. 
C)  slice thickness. 
D)  x-ray beam energy. A

Question 4

CT detectors are most commonly _____ detectors.

Accepted Answer

A)  ionization (xenon gas) 
B)  scintillation (solid state) 
C)  thermoluminescent 
D)  phosphorescent 
A)  ionization (xenon gas) 
B)  scintillation (solid state) 
C)  thermoluminescent 
D)  phosphorescent

Question 5

The measured x-ray transmission values are called:

Accepted Answer

A)  raw data. 
B)  pixels. 
C)  voxels. 
D)  Hounsfield units. 
A)  raw data. 
B)  pixels. 
C)  voxels. 
D)  Hounsfield units.

Question 6

The most common reporting method of dose reporting on the present scanners is:

Accepted Answer

A)  multiple scan average dose (MSA
D) . 
B)  computed tomography dose index (CTDI). 
C)  dose-length product (DLP). 
D)  computed tomography dose index volume (CTDIvol). 
A)  multiple scan average dose (MSA
D) . 
B)  computed tomography dose index (CTDI). 
C)  dose-length product (DLP). 
D)  computed tomography dose index volume (CTDIvol).

Question 7

Contrast is adjusted by windowing,changing window width and window level.Window width determines the:

Accepted Answer

A)  number of gray levels displayed. 
B)  midpoint of the gray range. 
C)  size of the field of view. 
D)  slice thickness. 
A)  number of gray levels displayed. 
B)  midpoint of the gray range. 
C)  size of the field of view. 
D)  slice thickness.

Question 8

Oral contrast for CT should be mixed so it is:

Accepted Answer

A)  the same as for general diagnostic examinations. 
B)  more concentrated than for general examinations. 
C)  less concentrated than for general examinations. 
D)  contrast media is not necessary. 
A)  the same as for general diagnostic examinations. 
B)  more concentrated than for general examinations. 
C)  less concentrated than for general examinations. 
D)  contrast media is not necessary.

Question 9

The reference material for CT is _____ and is related to the _____ of the tissue.

Accepted Answer

A)  water; field of view 
B)  water; linear attenuation coefficient 
C)  muscle; gray level 
D)  bone; mass attenuation 
A)  water; field of view 
B)  water; linear attenuation coefficient 
C)  muscle; gray level 
D)  bone; mass attenuation

Question 10

Contrast is adjusted by windowing,changing window width and window level.Window level determines the:

Accepted Answer

A)  number of gray levels displayed. 
B)  midpoint of the gray range. 
C)  size of the field of view. 
D)  slice thickness. 
A)  number of gray levels displayed. 
B)  midpoint of the gray range. 
C)  size of the field of view. 
D)  slice thickness.

Question 11

The CT system's ability to freeze any motion of a scanned object is termed:

Accepted Answer

A)  detector quantum efficiency. 
B)  temporal resolution. 
C)  reconstruction algorithm. 
D)  spatial resolution. 
A)  detector quantum efficiency. 
B)  temporal resolution. 
C)  reconstruction algorithm. 
D)  spatial resolution.

Question 12

CT is able to differentiate between tissues with similar densities compared with conventional radiography because of:

Accepted Answer

A)  digital magnification. 
B)  the use of a computer for data processing. 
C)  improved contrast resolution. 
D)  axial slices. 
A)  digital magnification. 
B)  the use of a computer for data processing. 
C)  improved contrast resolution. 
D)  axial slices.

Question 13

Which two factors affect image quality in CT? (Select all that apply.)

Accepted Answer

A)  Spatial resolution 
B)  Contrast media 
C)  Noise 
D)  Aperture size 
A)  Spatial resolution 
B)  Contrast media 
C)  Noise 
D)  Aperture size

Question 14

Dose in CT is considered to be:

Accepted Answer

A)  independent of size. 
B)  size dependent. 
C)  related to the CT numbers. 
D)  similar to a chest examination. 
A)  independent of size. 
B)  size dependent. 
C)  related to the CT numbers. 
D)  similar to a chest examination.

Exam 25: Computed Tomography

An array of numbers arranged in a grid of rows and columns is called a:

Which generation of CT scanners uses a dual-energy source (two x-ray tubes)?

The most significant geometric factor that contributes to spatial resolution is:

CT detectors are most commonly _____ detectors.

The measured x-ray transmission values are called:

The most common reporting method of dose reporting on the present scanners is:

Contrast is adjusted by windowing,changing window width and window level.Window width determines the:

Oral contrast for CT should be mixed so it is:

The reference material for CT is _____ and is related to the _____ of the tissue.

Contrast is adjusted by windowing,changing window width and window level.Window level determines the:

The CT system's ability to freeze any motion of a scanned object is termed:

CT is able to differentiate between tissues with similar densities compared with conventional radiography because of:

Which two factors affect image quality in CT? (Select all that apply.)

Dose in CT is considered to be:

Preliminary Steps in Radiography

General Anatomy and Radiographic Positioning Terminology

Thoracic Viscera: Chest and Upper Airway

Abdomen

Upper Extremity

Shoulder Girdle

Lower Extremity

Pelvis and Hip

Vertebral Column

Bony Thorax

Cranium

Trauma Radiography

Contrast Arthrography

Myelography and Other Central Nervous System Imaging

Digestive System: Salivary Glands, alimentary Canal, and Biliary System

Urinary System and Venipuncture

Reproductive System

Mammography

Bone Densitometry

Mobile Radiography

Surgical Radiography

Pediatric Imaging

Geriatric Radiography

Sectional Anatomy for Radiographers

Magnetic Resonance Imaging

Vascular,cardiac,and Interventional Radiography

Diagnostic Medical Sonography

Nuclear Medicine and Molecular Imaging

Radiation Oncology

Filters

The reference material for CT is _ and is related to the _ of the tissue.