CT TEST REVIEW QUESTIONS AND
ANSWERS
The main goal (s) in CT is to... - Answer--minimize superimposition
-improve contrast resolution
-provide a large amount of clinical information in a short amount of time
Arrange MR imaging, CT imaging and plain film x-ray imaging in order from best to
worst in their ability to diffeniate soft tissues in the body: - Answer-MRI is better than CT
is better than x-ray
Sectional images are obtained from all of the following except: - Answer-conventional
radiography
Which acronym has been established by the Radiological Society of North America in
major American radiology journals? - Answer-CT
Data acquisition refers to: - Answer-collecting x-ray transmission readings from the
patient
Which term describes the systematic motion of the x-ray tube as it rotates around the
patient to collect x-ray transmission readings? - Answer-scanning
Who developed the first clinically useful computed tomography scanner? - Answer-
Hounsfield
The detectors convert the attenuation data into _______________ signals. - Answer-
electrical
Who is considered the "Father of Computed Tomography"? - Answer-Godfrey
Hounsfield
Please choose all of the answers that apply.
What are the disadvantages of Computed Tomography? - Answer--cost
-high dose of radiation
Please click on all of the answers that apply.
The number of photons that interact with the tissues of the patient depends on the
tissues: - Answer--thickness
-density
-atomic number
The radiation used in Hounsfield's first experiments was: - Answer-gamma
, Computed tomography is able to quantify the beam attenuation of a given structure. The
measurements are expressed in ___________ units. - Answer-Hounsfield
The amount of the x-ray beam that is scattered or absorbed per unit thickness of the
absorber is expressed by the ______________. - Answer-linear attenuation co-efficient
____________________ is the collection of the x-ray transmission measurements from
the patient. - Answer-Data acquisition
In which of the following data acquisition methods are slices taken at a specific location
of the patient? - Answer-conventional slice by slice CT or Sequential CT
Raw data that has been segmented and averaged so that each pixel has an associated
Hounsfield Unit (HU) is ___________ data. - Answer-image
The degree to which the x-ray beam is reduced is a phenomenon referred to as
attenuation. - Answer-true
X-ray photons that pass through objects unimpeded are represented by white area on
the image. - Answer-False
In general, the attenuation co-efficient decreases with increasing photon energy and
increases with increasing atomic number and density. It follows that if the kVp is kept
constant, the linear attenuation co-efficient will be higher for bone that it would be for
lung tissue. - Answer-True
A homogeneous beam is comprised of photons that have different energies. - Answer-
False
Water Hounsfield number - Answer-0 HU
Air hounsfield number - Answer--1000 HU
Bone hounsfield number - Answer-+1000 HU
First Generation Scanner - Answer-Used a pencil beam and a single detector, took 5
minutes to produce an image
Second Generation Scanner - Answer-Used a fan beam and 1-2 detectors, took
approximately 20 seconds to produce an image
Third Generation Scanner - Answer-Used a fan beam and an arc of multiple detectors,
took about 1 second to produce an image
Fourth Generation Scanner - Answer-Used a fan beam and a complete circle of
detectors, took about 1 second to produce an image
ANSWERS
The main goal (s) in CT is to... - Answer--minimize superimposition
-improve contrast resolution
-provide a large amount of clinical information in a short amount of time
Arrange MR imaging, CT imaging and plain film x-ray imaging in order from best to
worst in their ability to diffeniate soft tissues in the body: - Answer-MRI is better than CT
is better than x-ray
Sectional images are obtained from all of the following except: - Answer-conventional
radiography
Which acronym has been established by the Radiological Society of North America in
major American radiology journals? - Answer-CT
Data acquisition refers to: - Answer-collecting x-ray transmission readings from the
patient
Which term describes the systematic motion of the x-ray tube as it rotates around the
patient to collect x-ray transmission readings? - Answer-scanning
Who developed the first clinically useful computed tomography scanner? - Answer-
Hounsfield
The detectors convert the attenuation data into _______________ signals. - Answer-
electrical
Who is considered the "Father of Computed Tomography"? - Answer-Godfrey
Hounsfield
Please choose all of the answers that apply.
What are the disadvantages of Computed Tomography? - Answer--cost
-high dose of radiation
Please click on all of the answers that apply.
The number of photons that interact with the tissues of the patient depends on the
tissues: - Answer--thickness
-density
-atomic number
The radiation used in Hounsfield's first experiments was: - Answer-gamma
, Computed tomography is able to quantify the beam attenuation of a given structure. The
measurements are expressed in ___________ units. - Answer-Hounsfield
The amount of the x-ray beam that is scattered or absorbed per unit thickness of the
absorber is expressed by the ______________. - Answer-linear attenuation co-efficient
____________________ is the collection of the x-ray transmission measurements from
the patient. - Answer-Data acquisition
In which of the following data acquisition methods are slices taken at a specific location
of the patient? - Answer-conventional slice by slice CT or Sequential CT
Raw data that has been segmented and averaged so that each pixel has an associated
Hounsfield Unit (HU) is ___________ data. - Answer-image
The degree to which the x-ray beam is reduced is a phenomenon referred to as
attenuation. - Answer-true
X-ray photons that pass through objects unimpeded are represented by white area on
the image. - Answer-False
In general, the attenuation co-efficient decreases with increasing photon energy and
increases with increasing atomic number and density. It follows that if the kVp is kept
constant, the linear attenuation co-efficient will be higher for bone that it would be for
lung tissue. - Answer-True
A homogeneous beam is comprised of photons that have different energies. - Answer-
False
Water Hounsfield number - Answer-0 HU
Air hounsfield number - Answer--1000 HU
Bone hounsfield number - Answer-+1000 HU
First Generation Scanner - Answer-Used a pencil beam and a single detector, took 5
minutes to produce an image
Second Generation Scanner - Answer-Used a fan beam and 1-2 detectors, took
approximately 20 seconds to produce an image
Third Generation Scanner - Answer-Used a fan beam and an arc of multiple detectors,
took about 1 second to produce an image
Fourth Generation Scanner - Answer-Used a fan beam and a complete circle of
detectors, took about 1 second to produce an image
